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9 Serious Vision Symptoms to Watch Out For

1. Flashing Lights, Floaters, or a Gray Shadow in Your Vision

The sudden onset of flashing lights, a noticeable increase in the amount of floaters, a shadow in your peripheral vision, or a gray curtain moving across your field of vision could be signs of a detachment of the retina — the nerve layer in the back of the eye that sends images to the brain. Nearsightedness, eye diseases like glaucoma, and physical injury to the eye are among the causes of retinal detachment. Unless treated quickly, usually with surgery, retinal detachment can lead to blindness.

2. Sudden Loss of Vision in One Eye

Sudden vision loss could signal a number of eye diseases and conditions. One is macular degeneration, also known as age-related macular degeneration or AMD, which is a leading cause of vision loss in people 65 and older in the United States. Vision loss caused by AMD can be gradual, but in some cases it can be sudden — when blood vessels in the eye leak fluid or blood under the retina, which is made up of nerve cells that allow you to see.

Another cause of sudden vision loss could be a type of glaucoma, which leads to a rapid buildup of fluid pressure in the eye that damages the optic nerve. There are many other conditions that can cause persistent loss of vision.

3. Eye Pain

Most eye diseases are painless, but some conditions or injuries can result in eye pain, says Richard Shugarman, MD, an ophthalmologist in West Palm Beach, Florida. Eye pain can be caused by glaucoma, dry eye, an eye injury, a scratched cornea, or even cancer of the eye.

4. Eye Injury

Any significant injury to the eye should be evaluated by a doctor, particularly if there is redness or pain that lasts for more than 15 to 20 minutes.

5. Persistent Discomfort in the Eye

If you experience any discomfort in your eye after doing an activity in which a small particle could have entered your eye, such as hammering or working under a car, don’t ignore it. Have your eyes checked out by a doctor to make sure that you don’t have a foreign particle in the eye, which can cause an infection.

6. Red Eye

“Having two red eyes is probably not as serious as one red eye,” says Dr. Shurgarman. When both eyes are red at the same time, it could be a sign of a cold or conjunctivitis (pink eye) — minor infections that are self-healing. But one red eye can be an indicator of a deeper inflammation, such as scleritis or uveitis. Scleritis is the inflammation of the tough, outer protective barrier around the eye, and uveitis is the inflammation and swelling of the middle coating of the eyeball.

7. Eye Discomfort if You Wear Contact Lenses

While most people who use contact lenses don’t experience problems when they follow the rules of proper contact lens care and use, serious infections can occasionally occur. If you wear contact lenses, never ignore eye pain, redness, or discomfort — see an eye doctor right away.

8. Blurred Vision

Even if it clears up, blurred vision can be a sign of a number of eye problems, such as glaucoma, uveitis, a torn retina, or AMD. Losing vision in one eye may be an early symptom of a stroke. “Vision loss, especially in one eye, could be a sign that the carotid artery, which is a major supplier of blood to the eyes, is blocked,” says Shugarman.

9. Eye Surgery Complication

If you’ve had eye surgery and experience any redness, eye pain, or blurring of vision, call your doctor right away for an evaluation.

Even if a symptom appears to go away, you’re better off checking with your eye specialist if you encounter any of these warning signs.

What are the Signs of Going Blind? (with pictures)

A variety of vision problems can be signs that someone is going blind; among these, blurriness, distortion, blind spots, light flashes, and double vision are some of the most common. Vision loss can be caused by many different risk factors and any symptoms should be regarded seriously. It should be noted, however, that just because an individual may have one or more of these signs, it does not automatically mean that blindness is imminent.

There are many causes of blindness. Stroke, epilepsy, migraine headaches, brain tumors, and injuries to the eye are just a few of the factors that can lead to an individual going blind. In most cases, the individual has a history of eye disorders or eye diseases, such as glaucoma, low vision, or detachment of the retinas. Macular degeneration, a progressive condition characterized by loss of vision brought on my retina damage, is another frequent cause of blindness.

Cloudy or blurred vision can be an early symptom. This condition creates hazy or shadowy eyesight and can be a telltale sign of any number of eye problems. Cloudy vision is often the first sign of more serious vision problems.

Distorted vision can be a scary but important sign of a serious eye problem. An individual with distorted vision sees shapes in an indistinct way. For example, when looking at a straight, flat surface like a desk or a countertop, someone with distorted vision may see the surface as undulating, warped, or uneven. This can be a symptom of macular degeneration, which can lead to blindness.

Blind spots are another frequent symptom of vision loss. When a specific area of the vision field becomes obstructed, the individual loses eyesight in that one location, creating a blind spot. This is a serious medical concern that can signify any number of health problems.

Many individuals who are going blind will experience flashing lights in their vision. These lights can be bright or dull and may be seen in any number of colors. Light flashes can signal retinal detachment or tears that may ultimately cause blindness.

When an individual sees two visual images instead of one, the condition is referred to as diplopia. Double vision is common with several conditions, both of the eye and other parts of the body. Sinus problems, thyroid conditions, and drug or alcohol addiction can produce this effect, but it is also a symptom of impending vision loss.

Feline Vision Problems: A Host of Possible Causes

In most cases, early diagnosis and treatment can keep a cat from losing its eyesight, but it’s important to look for signs of trouble and ensure your cat gets regular check-ups.

Cats have developed several unique vision features during their evolution that enable them to see clearly indoors and out. Unfortunately, these finely-tuned feline eyes are vulnerable to injury and a wide variety of diseases that can dramatically impair a cat’s eyesight or, in some cases, render a cat partially or totally blind.

“We see cats that are either blind or going blind several times a week,” says Thomas Kern, DVM, associate professor of ophthalmology at Cornell University’s College of Veterinary Medicine. “Most of these animals have eye disease as a primary disorder—they have no other health problems. And most of them are middle-aged or elderly cats whose vision loss has been progressing for years.”

As is true for virtually all threats to feline health, the earlier a cat’s vision problem is diagnosed, the more effectively it can be treated—unless, of course, the animal’s blindness has progressed irreversibly by the time it is noticed. Therefore, Dr. Kern urges owners to keep an eye out for any behavioral or physical indications that a cat is having a vision problem and to report any such signs to a veterinarian without delay.

Basic Components
Overall, feline eyes function in the same way that human eyes function and are made up of the same components. The major structural and functional components include:

  • Cornea, the transparent outer covering of the eyeball;
  • Pupil, the circular membrane in the center of the eye that permits the entry of light from the environment;
  • Iris, the round, pigmented membrane that surrounds the pupil and contracts or expands to regulate the amount of incoming light;
  • Lens, a transparent structure that adjusts its shape as needed to focus the light rays;
  • Retina, a sensitive membrane that lines the interior surface of the eyeball, receives the focused light impulses that have entered through the lens, and sends them along to the brain, as visual information;
  • Optic nerve, the conduit leading from the retina to the brain.

While structurally similar in most respects to human eyes, feline eyes have acquired over thousands of years a number of distinctive features that improve its chances for survival as both predator and prey. Among these features is a third eyelid—or “haw”—a thin, pale membrane positioned at the inner corner of the eye, between the lower eyelid and the eyeball. This extra eyelid helps keep the surface of a cat’s eyeball moist, protects it from being scratched by erratically growing hairs, and can help shield it during a scrap with a rival cat or other animal.

Cats also have a specialized layer of tissue beneath the retina that reflects incoming light. This structure—the tapetum lucidum—reflects light not absorbed by the retina during its first passage through the eye, thus giving the light a second chance to be absorbed and transmitted to the brain. Thanks to the tapetum lucidum, a cat’s sensitivity to light is thought to be about six times greater than that of a human’s.

Frequent Disorders
Cats are subject to a host of diseases that can cause permanent damage to any or all of the eye’s components. These disorders include cataracts, in which the lens gradually clouds up—often impenetrably—and prevents light from entering the eye; glaucoma, a condition marked by excessive fluid pressure within the eyeball that can cause it to harden; progressive retinal atrophy, in which the retinal tissue degenerates and loses its ability to function properly; and a variety of tumors—either malignant or benign—that develop within the eye or adjacent to it.

Many other feline eye diseases are attributable to viruses, bacteria and fungal organisms that specifically target cats—such as the feline immunodeficiency virus (FIV), the feline leukemia virus (FeLV), the feline infectious peritonitis virus (FIP), feline herpesvirus (FHP), toxoplasma (a parasitic organism) and cryptococcus (a yeast-like fungus commonly found in soil).

The most frequently diagnosed feline eye disorder, Dr. Kern notes, is conjunctivitis, an inflammation of the conjunctiva—the mucous membrane that lines the inner surface of the eyelid and the outer surface of the eyeball. This highly contagious condition, usually a by-product of an upper respiratory disease caused by either a bacterial or viral organism, is often observed in densely populated cat shelters, he notes. The disorder’s clearest symptom is runny eyes, and it is readily curable if treated promptly.

Severe Afflictions
Among the diseases that frequently lead to feline blindness, Dr. Kern says, the most common is inflammation of the uvea (uveitis), the middle area of the eye that is made up of the iris, the ciliary body (which produces the fluid inside the eye), and the choroid (which supplies nutrients to the retina). This disease, which is most often associated with FIV, FeLV, FIP and other infectious organisms, is usually chronic and is likely to result in gradual blindness. Among its signs are inflammation of the eyeball, squinting, swollen third eyelids and noticeably enlarged eyes.

The second most common blindness-causing disorder in cats, he says, is retinal detachment, a condition in which the retina becomes separated from its underlying tissue, typically resulting from a leakage or oversupply of fluid between the two layers. Retinal detachment is most frequently associated with high blood pressure, an overly active thyroid gland, or kidney disease. In some instances, prompt and proper veterinary treatment can restore partial vision to a cat with a retinal detachment, but in most cases, permanent blindness will result.

Cats’ eyes are also vulnerable to traumatic and potentially blinding injuries, notes Dr. Kern, such as corneal lacerations (cuts on the outer surface of the eye), which are common. As is the case with virtually all types of feline health problems, the earlier a cat’s vision impairment is diagnosed—whether the result of disease or injury—the better it may be treated. In some cases, unfortunately, an animal’s failing vision or blindness may have become irreversible by the time veterinary care is pursued.

Signs Your Dog May Be Going Blind

Key Takeaways

  • A particularly common issue that affects senior dogs is vision impairment.
  • There are several signs to look for to determine if your dog is losing vision, including loss of interest in exploring or playing, white spots or cloudy eyes, and clumsy behavior or running into things.
  • Dogs with impaired vision can still live happy and full lives. It just requires a little extra attention to detail, patience, and TLC from their owners to help navigate the world around them

Just like humans, dogs experience a range of issues as they grow into their golden years. A particularly common issue that affects senior dogs is vision impairment. This is typically caused by cataracts, glaucoma, macular degeneration, and can sometimes be the side effect of other medical disorders such as hypertension, chronic dry eye, and diabetes.

It’s very rare for blindness to happen “overnight.” Full impairment can take many months or even years, which makes it particularly hard to diagnose early unless you’re explicitly looking for symptoms. Below we’ve outlined signs to look for and have also included best care practices for dogs with impaired vision.

Common Signs a Dog is Losing Their Vision

Because blindness happens so gradually, it can be difficult to notice signs. In some cases, blindness symptoms can even be mistaken for other conditions.

Subtle Signs

  • Lethargy
  • Not venturing into new spaces / sticking to the same rooms in your home
  • Aggressive or defensive behavior
  • Anxiety, fear, and depression
  • Reduced desire to play/engage in previous activities they loved

Clearer Signs

  • White Spots or Cloudy Eyes — If you observe small white spots or an opaque veil over the entire eye, this is indicative of glaucoma or cataracts. Since both happen slowly over time, we recommend comparing your dog’s eyes with images that were taken several years ago to see if there’s been a notable change.
  • Abnormal Pupil Dilation — Canine pupils should adjust in dark and bright light as human eyes do. You can test your dog’s dilation with a flashlight. Pupils that don’t dilate are a sign of blindness.
  • Reduced or No Eye Contact — If your dog was once eager to look you in the eyes but stops doing so, it’s a sign that he or she may be losing their vision.
  • Clumsy Behavior — Dogs that bump into furniture, misjudge their leaps, or generally act clumsy, may be doing so because they can’t see clearly. This can be especially pronounced when you rearrange furniture or when you take your pup to a new location.

If you suspect your dog’s vision is impaired, consult your veterinarian right away. At your appointment, clearly convey your concerns and explain some of the behaviors you’ve noticed. Your vet will carefully examine your dog, perform some tests, and make a diagnosis.

Treatment Options

Treatment is highly dependent on the cause of your dog’s blindness, as well as how quickly the issue is caught. For example, roughly 40% of dogs that develop glaucoma will eventually go blind, and cataracts can result in permanently impaired vision if not treated promptly. Conversely, minor trauma to the eye from accidents or infection is far less likely to lead to permanent blindness. It’s important to see a vet immediately if you suspect anything is wrong with your dog’s eyes. He or she can provide you with a diagnosis and treatment plan.

Caring for a Blind Dog

Dogs with impaired vision can still live happy and full lives. It just requires a little extra attention to detail, patience, and TLC from their owners to help navigate the world around them. If your dog is going blind, or is already blind, the following can help make their lives more comfortable.

  • Keep things predictable — always place water and food in the same spot and avoid rearranging your home. If you must make a change, carefully guide your pet through the changes so they know what’s different.
  • Provide a safe space — a small, unchanging room or even large kennel can serve as a safe and predictable space for your pooch. Make this area comfortable by providing cozy blankets and items with your scent.
  • Dog proof your home — look at your home and yard from the perspective of a blind dog. Where might your pooch bump into dangerous objects? Knock things over? Fall? Unknowingly stray? These potential hazards should be addressed promptly.
  • Announce Yourself — Blind dogs rely on sound and vibrations. To prevent startling your pooch, walk with heavy steps or say hello when you enter a room. Also make sure to announce yourself before petting on snuggling.
  • Practice patience — it may be frustrating if your dog keeps knocking objects over or whimpers and barks excessively. Instead of getting annoyed, use these moments to practice extra patience and shower your pet with love and affection.

Eye conditions are common across all ages, but by enrolling in pet insurance before your pup exhibits symptoms, claims will be covered.. If you aren’t already a pet parent with us, look into getting a free quote to help safeguard not just your dog, but your wallet too.

Tips to prevent vision loss

Follow these simple guidelines for maintaining healthy eyes well into your golden years.

Your eyes are an important part of your health. You can do many things to keep them healthy and make sure you’re seeing your best. Follow these simple guidelines for maintaining healthy eyes well into your golden years.

Have a comprehensive dilated eye exam. You might think your vision is fine or that your eyes are healthy, but visiting your eye care professional for a comprehensive dilated eye exam is the only way to really be sure. When it comes to common vision problems, some people don’t realize they could see better with glasses or contact lenses. In addition, many common eye diseases, such as glaucoma, diabetic eye disease, and age-related macular degeneration, often have no warning signs. A dilated eye exam is the only way to detect these diseases in their early stages.

During a comprehensive dilated eye exam, your eye care professional places drops in your eyes to dilate, or widen, the pupil to allow more light to enter the eye—the same way an open door lets more light into a dark room. This process enables your eye care professional to get a good look at the back of the eyes and examine them for any signs of damage or disease. Your eye care professional is the only one who can determine if your eyes are healthy and if you’re seeing your best.

Maintain your blood sugar levels. 90% of blindness caused by diabetes is preventable. Ask your health care team to help you set and reach goals to manage your blood sugar, blood pressure, and cholesterol—also known as the ABCs of diabetes.

  • A1c: The goal set for many people is less than 7% for this blood test, but your doctor might set different goals for you.
  • Blood pressure: High blood pressure causes heart disease. The goal is less than 140/90 mmHg for most people, but your doctor might set different goals for you.
  • Cholesterol: LDL or “bad” cholesterol builds up and clogs your blood vessels. HDL or “good” cholesterol helps remove the “bad” cholesterol from your blood vessels. Ask what your cholesterol numbers should be.

Know your family’s eye health history. Talk to your family members about their eye health history. It’s important to know if anyone has been diagnosed with an eye disease or condition, since many are hereditary. This information will help to determine if you’re at higher risk for developing an eye disease or condition.

Eat right to protect your sight. You’ve heard that carrots are good for your eyes. But eating a diet rich in fruits and vegetables—particularly dark leafy greens, such as spinach, kale, or collard greens—is important for keeping your eyes healthy, too.i Research has also shown there are eye health benefits from eating fish high in omega-3 fatty acids, such as salmon, tuna, and halibut.

Maintain a healthy weight. Being overweight or obese increases your risk of developing diabetes and other systemic conditions, which can lead to vision loss, such as diabetic eye disease or glaucoma. If you’re having trouble maintaining a healthy weight, talk to your doctor.

Wear protective eyewear. Wear protective eyewear when playing sports or doing activities around the home. Protective eyewear includes safety glasses and goggles, safety shields, and eye guards specially designed to provide the correct protection for the activity in which you’re engaged. Most protective eyewear lenses are made of polycarbonate, which is 10 times stronger than other plastics. Many eye care providers sell protective eyewear, as do some sporting goods stores.

Quit smoking or never start. Smoking is as bad for your eyes as it is for the rest of your body. Research has linked smoking to an increased risk of developing age-related macular degeneration, cataract, and optic nerve damage, all of which can lead to blindness.ii, iii

Be cool and wear your shades. Sunglasses are a great fashion accessory, but their most important job is to protect your eyes from the sun’s ultraviolet rays. When purchasing sunglasses, look for ones that block out 99 to 100 percent of both UV-A and UV-B radiation.

Give your eyes a rest. If you spend a lot of time at the computer or focusing on any one thing, you sometimes forget to blink and your eyes can get fatigued. Try the 20-20-20 rule: Every 20 minutes, look away about 20 feet in front of you for 20 seconds. This short exercise can help reduce eyestrain.

Clean your hands and your contact lenses—properly. To avoid the risk of infection, always wash your hands thoroughly before putting in or taking out your contact lenses. Make sure to disinfect contact lenses as instructed and replace them as appropriate. Learn more about keeping your eyes healthy while wearing contact lenses and listen to a podcast on keeping your eyes safe.

Practice workplace eye safety. Employers are required to provide a safe work environment. When protective eyewear is required as a part of your job, make a habit of wearing the appropriate type at all times, and encourage your coworkers to do the same.


i Age-Related Eye Disease Study Research Group. The relationship of dietary carotenoid with vitamin A, E, and C intake with age-related macular degeneration in a case-control study. Archives of Ophthalmology 2007; 125(9): 1225–1232.

iiAge-Related Eye Disease Study Research Group. Risk factors associated with age-related nuclear and cortical cataract. Ophthalmology 2001; 108(8): 1400–1408.

iii U.S. Department of Health and Human Services, Office of the Surgeon General. The Health Consequences of Smoking: A Report of the Surgeon General (Washington, D.C., 2004).

Adapted from National Eye Institute external icon
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Glossary of Eye Conditions | American Foundation for the Blind

A – B – C – D – E – F – G – H – I – J – K – L – M – N
O – P – Q – R – S – T – U – V – W – X – Y – Z


Rare, inherited vision disorder in which a person has little or no ability to see color. People with achromatopsia also commonly experience some vision loss, especially in bright light, to which they are extremely sensitive. The severity of achromatopsia varies. Although there is no cure or treatment for this disorder, people with achromatopsia can manage its symptoms. For example, they can wear sunglasses or tinted contact lenses to cope with bright light. They can use magnifiers and other devices for low vision to help them read, and telescopes to help them see distant objects.

Suggested resource: www.achromat.org

Acute Zonal Occult Outer Retinopathy (AZOOR)

Acute zonal occult outer retinopathy (AZOOR) is a retinal disease characterized by sudden onset of flashing lights and visual field changes in an individual with a normal retinal exam. It affects women 3 times more frequently than men; most people affected are Caucasian, middle-aged, and myopic. A viral illness has preceded many of the reported cases. Initially only one eye is involved but the other eye may be affected months to years later.

Age-related macular degeneration (ARMD)

See macular degeneration.

Suggested resources:
Age-Related Macular Degeneration



A hereditary condition characterized by a variable lack of pigment in the eyes, skin, or hair. People with albinism may have pale pink skin and blond to white hair, but there are different types of albinism, and the amount of pigment varies. The irises of their eyes may be white or pinkish. They are sensitive to bright light and glare and commonly have other vision problems. While some people with albinism can see well enough to drive, many have impaired vision or may even be legally blind. Albinism is often accompanied by nystagmus or strabismus. People with albinism are sensitive to bright light and glare and may wear tinted eyeglasses. Bifocals, magnifiers, and other optical devices can help people with albinism.

Suggested resources:


A condition in which a person’s vision does not develop properly in early childhood because the eye and the brain are not working together correctly. Amblyopia, which usually affects only one eye, is also known as “lazy eye.” A person with amblyopia experiences blurred vision in the affected eye. However, children often do not complain of blurred vision in the amblyopic eye because this seems normal to them. Early treatment is advisable, because if left untreated, this condition may lead to permanent vision problems. Treatment options include vision therapy exercises or prescription eyeglasses. People with amblyopia may need to wear an eye patch over their stronger eye in order to force the affected eye to function as it should.

Suggested resources:


Partial or complete absence of the iris of the eye. This rare condition, usually present at birth, results in impaired vision and sensitivity to light. People with aniridia are also at high risk for certain other eye conditions, such as glaucoma, nystagmus, and cataracts. People with aniridia may benefit from wearing tinted contact lenses or sunglasses, using magnifiers, and avoiding intense or glaring light.

Suggested resources:


Rare condition in which one or both eyes do not form during pregnancy. When both eyes are affected, blindness results. There is no cure for anophthalmia. Prosthetic eyes can promote proper growth of the eye sockets and development of facial bones and also serve cosmetic purposes.

Suggested resource: www.nei.nih.gov/health/anoph/anophthalmia


Absence of the lens of the eye. Aphakia is usually associated with the surgical removal of a cataract but may also result from a wound or other cause. Without the lens, the eye cannot adjust its focus for seeing at different distances. Contact lenses or eyeglasses are used to correct the vision of someone with aphakia. In cataract surgery, an artificial lens is inserted to replace the lens removed. A person with aphakia will benefit from good, but not excessive, lighting and high-contrast reading materials.

Suggested resource: http://www.tsbvi.edu/curriculum-a-publications/970-aphakia


Common vision condition, usually present from birth, caused by an irregularly curved cornea or lens. People with astigmatism may experience blurred vision, eyestrain, or headaches. Two-thirds of Americans who have myopia also have astigmatism. Astigmatism can be corrected with eyeglasses or contact lenses. Corrective surgery is another option.

Suggested resource: https://www.nei.nih.gov/health/astigmatism

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A condition in which the lens of the eye, which is normally clear, becomes cloudy or opaque. Cataracts generally form slowly and without pain. They can affect one or both eyes. Over time, a cataract may interfere with vision, causing images to appear blurred or fuzzy and colors to seem faded. Most cataracts are related to aging. In fact, cataracts affect more than 50 percent of all adults by age 80 and are the primary cause of vision loss in people 55 and older. People with early cataract may benefit from new eyeglasses, bright lighting, anti-glare sunglasses, or magnifying lenses. If, despite such devices, cataract interferes with daily activities, surgery is the only effective treatment. Cataract surgery, which is common, involves removal of the cloudy lens and replacement with an artificial lens.

Suggested resources:

Charles Bonnet syndrome

Visual disturbances usually occurring in people who have experienced visual impairment or sight loss later in life, as through macular degeneration. People with Charles Bonnet syndrome may see a wide range of images, from simple patterns to people, animals, and buildings. The visual disturbances associated with this syndrome are not signs of mental illness, and people realize that the images they are seeing are not real. There is no cure for Charles Bonnet syndrome. However, the symptoms often stop on their own. People who have Charles Bonnet syndrome should consult with an eye care specialist because treatment for vision disorders may help.

Suggested resources:
Charles Bonnet Syndrome

Chorioretinal Atrophy
Chorioretinal atrophy is, as the name implies a degeneration, or atrophy of the retina. It affects males more than females. It is an autosomal dominant disorder caused by mutations in the CRB1 gene.
Choroidal Neovascularization
Choroidal neovascularization refers to new and abnormal blood vessels that grow, multiply, and develop into a cluster beneath the macula. The macula is the part of the retina that provides the clearest central vision.

Rare disorder that causes progressive loss of the choroid, an important layer under the retina that is responsible for some of its blood supply. Choroideremia is an inherited disorder that generally affects males only. It commonly begins as night blindness in childhood and gradually advances to increasing vision loss. Most people with this disorder are able to retain good vision until age 40 or 50. There is no treatment for choroideremia, but people who have the disorder may find it helpful to use optical, electronic, or computer-based devices for low vision.

Suggested resource: http://curechm.org/what-is-choroideremia/


A cleft or gap in some part of the eye, such as the iris, lens, or retina, that is caused by a defect in the development of the eyeball. How much coloboma affects a person’s vision depends on the size and location of the cleft and on whether it occurs in one or both eyes. For example, someone with only a tiny defect in the iris may have normal vision. However, a person with large defects in the retina and optic nerve may have limited vision. Children whose vision is impaired by coloboma may benefit from using reading materials that have large black print and well-spaced letters and words. They may also find it helpful to read one line at a time with the aid of a cutout reading window.

Suggested resource: http://www.tsbvi.edu/curriculum-a-publications/977-coloboma

Color blindness

A vision problem in which a person has difficulty distinguishing certain colors—most commonly red and green, but sometimes blue and green or blue and yellow. Color blindness is not really a form of blindness, but rather a deficiency in color perception. It usually affects both eyes and is much more common in males than in females. There is no treatment or cure for this problem, but a color-blind person can learn to adapt in various ways. For example, a color-blind driver can remember that the light positioned at the top of a traffic light is the red one. It is beneficial to diagnose color blindness in children at an early age so that steps can be taken to avoid learning problems related to color perception.

Suggested resource: http://www.tsbvi.edu/instructional-resources/69-information-about-color-and-color-blindness

Cone-rod dystrophy

Inherited disease that, over time, causes deterioration of the specialized light-sensitive cells of the retina. People with cone-rod dystrophy typically experience decreased sharpness of vision followed by a loss of peripheral vision and color perception. The most common form of cone-rod dystrophy is retinitis pigmentosa. There is no treatment or cure for this disease, which is also referred to as cone-rod degeneration, progressive cone-rod dystrophy, and retinal cone dystrophy.

Suggested resources:

Congenital eye defects
Any of various conditions present at birth that affect the eyes or vision. Some congenital eye conditions, such as retinitis pigmentosa, are passed on through genes. Others, such as vision loss due to German measles, result from a disease or deficiency during pregnancy. Sometimes, as in the case of coloboma, the cause of a congenital eye defect is not known. Congenital eye defects can impair vision or even cause blindness. Some conditions are immediately apparent in an infant, while others may not become known until later in life.

Conjunctivitis is inflammation of the conjunctiva, which is the thin translucent tissue that lines the inner surface of the eyelid and the outer surface of the sclera, which is the white part of the eye.

Conjunctivitis is usually associated with redness of the white part of the eyes, light sensitivity (photophobia), excessive tearing, ocular discomfort (gritty sensation, itching, burning), and/or discharge.

There are many different causes of conjunctivitis. Some types of conjunctivitis are infectious, while others are not. These can generally be differentiated from one another based on history and an examination by an eye doctor.

Suggested Resource: Conjunctivitis

Corneal disease

Disease or disorder that affects the cornea, the clear, curved surface that covers the front of the eye. The effects of corneal disease vary. Some corneal conditions cause few, if any, vision problems. For example, infections of the cornea can often be treated with antibiotics. However, if the cornea becomes cloudy, light cannot penetrate the eye to reach the retina, and severe visual impairment, or even blindness, may result. Corneal dystrophies are usually inherited conditions in which one or more parts of the cornea lose their clarity due to a buildup of cloudy material. Keratoconus is the most common corneal dystrophy in the United States. When corneal disease causes the cornea to become permanently clouded or scarred, doctors may be able to restore vision with a corneal transplant—surgical replacement of the old cornea with a new one.

Suggested resource: http://www.nei.nih.gov/health/cornealdisease/

Cortical visual impairment

Visual impairment caused by damage to those parts of the brain related to vision. Although the eye is normal, the brain cannot properly process the information it receives. The degree of vision loss may be mild or severe and can vary greatly, even from day to day. Also known as cerebral visual impairment, cortical visual impairment (CVI) may be temporary or permanent. People with cortical visual impairment have difficulty using what their eye sees. For example, they may have trouble recognizing faces, interpreting drawings, perceiving depth, or distinguishing between background and foreground. Children with cortical visual impairment are often able to see better when told in advance what to look for. Cortical visual impairment is also known as neurological visual impairment (NVI).

Suggested resources:
Cortical Visual Impairment, Traumatic Brain Injury, and Neurological Vision Loss — www.afb.org/cvi


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Macular degeneration

Disease that causes dysfunction of the macula, the area in the middle of the retina that makes possible the sharp central vision needed for such everyday activities as reading, driving, and recognizing faces and colors. The condition is commonly known as age-related macular degeneration (AMD) and is the leading cause of visual impairment among older people. However, there are also other types of macular degeneration, such as Stargardt’s Disease and Best’s Disease. Macular degeneration causes blurred, distorted, or dim vision or a blind spot in the center of the visual field. Peripheral vision is generally not affected. This condition is painless and may progress so gradually that the affected person at first notices little change. There is no cure for macular degeneration, but drug therapy, laser surgery, or other medical treatment may in some cases be able to slow the disease’s progression or prevent further vision loss. People with macular degeneration can also benefit from the use of various devices for low vision, such as magnifiers, high-intensity lamps, and pocket-sized telescopes.

Suggested resources:
Age-related Macular Degeneration (AMD)

Macular hole

A macular hole is a full thickness hole in the central part of the retina called the macula. It may be caused by injury or inflammatory swelling of the retina, but most commonly occurs as an age-related event without any predisposing conditions. Macular holes are thought to be caused by tractional forces associated with the vitreous gel separating from the retina in the macula and around the central macula called the fovea. Surgery is the treatment of choice for full-thickness macular holes.

Suggested resources:
Macular Hole

Marfan Syndrome

Disorder of the connective tissue, affecting the heart and blood vessels, skeletal system, eyes, and other parts of the body. The condition is present at birth. Symptoms vary from person to person, ranging from mild to severe. People with Marfan syndrome are often nearsighted (see myopia), and about half have dislocation of one or both lenses of the eye. There is no cure for Marfan syndrome. Treatment depends on which body systems are affected. Early eye examinations can detect vision problems related to the disorder, which can usually be corrected with eyeglasses, contact lenses or eye surgery.

Suggested resource: www.marfan.org


Rare disorder, usually inherited, in which one or both eyes are abnormally small. The degree of visual impairment varies, from reduced vision to blindness. Extreme microphthalmia resembles some forms of anophthalmia. There is no treatment or cure for microphthalmia. In certain cases, artificial eyes can be used to promote proper growth of the eye sockets and to help with cosmetic appearance.

Suggested resource: http://www.nei.nih.gov/health/anoph/


This condition, commonly known as nearsightedness, occurs when light rays entering the eye focus in front of the retina, not directly on it. People with myopia are usually able to see close objects well, but objects in the distance—such as highway signs or writing on a chalkboard—appear blurred. People with this condition may squint to see distant objects and experience eyestrain or, sometimes, headaches. Eyeglasses or contact lenses can correct myopia. Surgery is another alternative.

Suggested resource: https://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/myopia

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Neurological visual impairment (NVI)

See cortical visual impairment.

Suggested resource: www.sfsu.edu/~cadbs/Eng022.html

Neuromyelitis optica (NMO)
Neuromyelitis optica (NMO), also known as Devic’s disease, is an autoimmune disorder in which immune system cells and antibodies mistakenly attack and destroy myelin cells in the optic nerves (neuritis) and the spinal cord (myelitis). NMO leads to loss of myelin, which is a fatty substance that surrounds nerve fibers and helps nerve signals move from cell to cell. The syndrome can cause blindness in one or both eyes and can be followed by varying degrees of paralysis in the arms and legs. Most individuals with the syndrome experience clusters of attacks months or years apart, followed by partial recovery during periods of remission. The onset of NMO varies from childhood to adulthood, with two peaks, one in childhood and the other in adults in their 40s. The syndrome is sometimes confused with multiple sclerosis (MS) because both can cause attacks of optic neuritis and myelitis.
Non-24-Hour Sleep-Wake Disorder (Non-24)

Non-24-Hour Sleep-Wake Disorder (Non-24) is a serious, chronic, and rare circadian rhythm disorder that affects a majority of totally blind individuals who lack light perception and cannot reset their master body clocks to the 24-hour day. Non-24 is most commonly found in blind individuals who cannot perceive light, the primary environmental cue for synchronizing their circadian rhythm to the 24-hour day. In the United States, this disorder affects approximately 80,000 totally blind individuals who lack the light sensitivity necessary to reset their internal “body clocks.” In general, individuals with Non-24 suffer from a variety of clinical symptoms as they cycle into and out of phase, resulting in disrupted nighttime sleep patterns and/or excessive daytime sleepiness.

Suggested resources:
FDA Approval for Drug That Regulates Sleep Patterns
Discovering That I Had Non-24


Condition that involves involuntary, rapid, repetitive movements of one or both eyes from side to side, up and down, or in a circular motion. Nystagmus may be present at birth or, less commonly, may result from disease or injury. In some cases, the condition can reduce or interfere with vision. For example, children with nystagmus may frequently lose their place when reading. Placing a cutout reading window over words or using a card to “underline” text can be helpful.

Suggested resource: www.nystagmus.org

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Retinal detachment

Separation of the retina from the underlying supportive tissues. Retinal detachment may result from injury, disease, or other causes. A person with retinal detachment usually does not experience pain, but may see floaters (see floaters and spots) or bright flashes of light, may have blurred vision, or may see a shadow or curtain over part of the field of vision. Retinal detachment requires prompt medical attention to prevent permanent vision loss. There are several methods of treatment for retinal detachment, including laser surgery.

Suggested resource: www.nei.nih.gov/health/retinaldetach/index.asp

Retinitis pigmentosa

Degeneration of the retina, resulting in decreased night vision, a gradual loss of peripheral vision, and in some cases, loss of central vision. The degeneration progresses over time and can lead to blindness. Retinitis pigmentosa is a rare, inherited disease for which there is as yet no treatment or cure. Some ophthalmologists believe that treatment with high doses of Vitamin A can slow the progression of retinitis pigmentosa, and that taking Vitamin E makes it worse. Early diagnosis enables a person with the disease to plan and prepare for its progression. In addition, depending on the degree of vision loss, electronic magnifiers, night-vision scopes, and other such special devices for impaired vision can provide some benefit for people with the disease.

Suggested resource:


Malignant tumor (cancer) of the retina, generally affecting children under the age of 6. Usually hereditary, retinoblastoma may affect one or both eyes. Retinoblastoma has a cure rate of over 90 percent if treated early. Without prompt treatment, the cancer can spread to the eye socket, the brain, and elsewhere, and can cause death. Depending on the size and location of the tumor, treatment options include laser surgery, cryotherapy (a freezing treatment), radiation, and chemotherapy. In some cases, the affected eye may need to be removed.

Suggested resource: www.aoa.org/x8066.xml

Retinopathy of prematurity (ROP)

Condition associated with premature birth, in which the growth of normal blood vessels in the retina stops, and abnormal blood vessels develop. As a result, the infant has an increased risk of detachment of the retina (see retinal detachment). Retinopathy of prematurity can lead to reduced vision or blindness. Laser therapy can help this condition if diagnosis and treatment occur early. Children who experience minor effects may benefit from the use of devices for low vision as they get older. Retinopathy of prematurity was formerly called retrolental fibroplasia.

Suggested resources:

Retrolental fibroplasia
See retinopathy of prematurity.
Rod-cone dystrophy

See Cone-rod dystrophy.

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Gap or blind spot in the field of vision that may result from damage to the retina. How much a scotoma impairs sight depends mainly on whether it affects central or peripheral vision. Common causes of scotoma include macular degeneration, glaucoma, and inflammation of the optic nerve. People who experience significant vision loss because of scotomas may benefit from the use of magnifiers, bright lighting, and large-print reading materials.

Suggested resource: http://www.tsbvi.edu/curriculum-a-publications/1093-scotoma

Septo-Optic Dysplasia (SOD)

See De Morsier’s Syndrome.

Suggested resources:


Stargardt’s Disease

Inherited disease that causes gradual degeneration of the macula, the area in the middle of the retina that makes possible the central vision needed for reading, driving, recognizing colors, and other activities of daily life. Effects of Stargardt’s Disease, which start at an early age, vary from minor to total loss of detail vision. Over a period of years, people with the disease typically lose sharpness of vision, experience decreased color vision, and may have blind spots. However, peripheral and night vision usually remain unaffected, and complete loss of sight is rare. There is no cure or treatment for Stargardt’s Disease, but such devices as magnifying screens and binocular lenses can help people cope with vision limitations.

Suggested resource:


Condition in which the eyes are not both directed toward the same point simultaneously. Strabismus occurs when eye muscles are not working together properly. It is most commonly an inherited condition, but may also be caused by disease or injury. If diagnosed early, strabismus can usually be corrected. The condition may be treated with corrective eyeglasses, eye-muscle exercises, surgery, or a combination of these approaches. Young children with this condition may need to wear an eye patch over their stronger eye to force their weaker eye to function correctly. Children whose strabismus is not corrected may develop amblyopia.

Suggested resource: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/strabismus?sso=y

Sturge-Weber Syndrome

Disorder, present at birth, characterized by a facial birthmark and any of various neurological, visual, and developmental symptoms. People with Sturge-Weber syndrome may, for example, experience seizures, glaucoma, partial paralysis, and learning disabilities. There is no cure for Sturge-Weber syndrome, but many of the symptoms can be treated. For instance, medications may be prescribed to control seizures, and surgery or eye drops may be used to treat glaucoma.

Suggested resource: http://sturgeweber.kennedykrieger.org/

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Thyroid eye disease (TED) is an inflammatory condition closely associated with Graves’ disease. In thyroid eye disease (also called Graves’ Orbitopathy, Graves’ Eye Disease, or Graves’ ophthalmopathy), the immune system sets off an abnormal reaction to the muscles and fatty tissue around the eyes. The symptoms that occur in thyroid eye disease include bulging eyes, swollen eyes, redness, misaligned eyes, tenderness or eye pain, and problems with vision such as light sensitivity, blurriness, or double vision. Although many patients with thyroid eye disease will have abnormal blood tests for thyroid hormone levels, some people experience eye symptoms even though their hormone levels are normal.

How to Tell if your Dog is Going Blind

Vision loss can affect dogs in the same way that it affects humans. As your canine companion ages, they can start to go blind. Some even lose vision in one eye while retaining their abilities in the other.

* Dogs of any breed and age can be affected. However,

it’s most common in older dogs and those that are genetically predisposed to ocular issues.

It can be difficult to determine if your pup’s vision is starting to deteriorate. Dogs can be masters of deception. They’ll do all that they can to get by and make sure that you don’t know that they’re suffering. They’ll use their other senses to make up for their lack of vision.

In many cases, owners won’t even realize that their poor puppy is having vision issues until up to 80% of their abilities are gone.

With all that being said, there are ways that you can check your dog’s vision at home. These tests are simple enough and will let you know if you need to take your furry friend to the veterinarian.

Finding a Base Line

Before you start testing for poor ocular health, you should have a general idea of how your dog sees the world normally. It’s important to use this test early on in your dog’s life so that you can use the information you gather as a comparison with tests in the future.

It should be noted that this test is by no means scientific and should never replace professional alternatives. Instead, it’s meant to give you a general idea of how well your pup can see.

First, have another person hold your dog in place. While that’s being done, gather one of your dog’s favorite toys. Avoid any brightly colored options, as these are typically easier to see than normal ones. Start off at a distance and slowly walk towards your dog until they notice the toy and get excited.

This distance can be used as a baseline. You can perform this test regularly throughout your dog’s life so that you always know how their vision is degenerating.

Physical Symptoms

In some cases, you may be able to see physical signs of vision impairment. These symptoms indicate an underlying cause that may be treatable, so it’s important that you contact a vet as soon as you notice these changes. 

One of the most common issues is fuzziness on the eye. Small cloudy spots can form on the surface of the eyeball and impair your dog’s vision. These are a result of Glaucoma.

Glaucoma is a disease that affects the optic nerve. Increased pressure in the eye prevents fluid from escaping, resulting in the cloudiness. Even small opaque spots can spread and render your dog blind. Smaller spots are easier to manage for dogs. They can use the other eye or see around the spot.

Dilation Test

A dog’s eyes will dilate and constrict like yours do. Healthy pupils will open up in darker environments and constrict in brighter ones. This process helps to regulate how much light is getting into the back of the eye.

To perform this test, have your dog down and grab a standard small flashlight. Avoid using high-powered lights that could hurt your dog. Then, simply shine the light over the eyes.

You should notice that the pupils constrict when they’re exposed to light. If they stay dilated even when the light is directly over them, your dog may already be blind. A lack of dilation indicates that the light isn’t able to to the back of the eye. Take your pup to the vet for a proper diagnosis.

Nighttime Obstacle Test

One of the reasons why so many pet owners fail to realize that their dog is losing his or her vision is because they don’t have problems getting around the house. When they’re not bumping into furniture every few minutes they must be able to see, right?

In reality, dogs probably have the layout of your home memorized. They know exactly where each couch or side table is.

One easy way to see if your dog is slowly going blind is to rearrange some furniture and set up an obstacle course. It’s best to do this at night because night vision is often the first to go. If you were to perform it during the day, your pup may use what remaining vision they have to complete it.

Once you’ve moved furniture in places your dog would not expect it to be, place them on one end of the room and call out to them.

It’s important that you call out only once. They’ll use the constant sound of your voice to get through if you call repeatedly.

If your dog bumps into furniture, they are suffering from vision impairment.

Reflex Test

Also known as the Menace Response Test, this method can help you determine how your dog responds to objects coming close. Dogs will instinctively blink their eyes as an obstacle approaches. However, if they can’t see, this won’t happen. 

Place your dog in a room that has normal lighting. Then, use one hand to cover one eye. It’s important to test one eye at a time to ensure that you can get accurate results.

Bring your other hand close to their opened eye slowly. You should be coming from the corner of the eye so that your hand comes into their vision. Make sure to do this part slowly. If you move to fast, you may create a small push of air that alerts them. Also, avoid touching their whiskers. Your dog should start blinking. If not, take them to a vet.

Cotton Ball Test

This test is very similar to the previous one. However, it tests your dog’s ability to follow moving objects with their eyes. Start by covering up a single eye. Now take a small cotton ball and drop it approximately 6 inches from their eyes.

Drop it from a height above their head where they can’t see it. Once the ball drops, your dog’s eyes should follow its motions. They may even try to eat it or give it a good sniff when it comes down. These are all good signs. If your dog doesn’t respond at all, they are suffering from ocular problems.

You can perform this test at varying distances to test how well your dog can see. It’s important that you always use a dry cotton ball. Cotton balls don’t make any sound when they hit the floor, so there’s no way that your dog can use his or her other senses to find it.

Taking Your Dog To A Vet

If your dog fails any of these tests, a trip to the vet is crucial. They’ll be able to perform a routine eye examination to get a better understanding of what issues they’re facing. They may also refer you to an animal ophthalmologist. An ophthalmologist is better-equipped to perform an in-depth analysis of your dog’s overall ocular health.


While going blind may be common in dogs, there are things that you can do to protect your dog’s vision. Depending on your dog’s particular needs, your veterinarian may create a treatment plan. This plan can include a high-quality diet, medication, or even surgery.

You can use these tests to catch the problem early on. You’ll have a better chance of saving your dog’s vision the earlier you can get them the care that they need.

Also Read:  Toys for Blind Dogs – 7 Top Picks

Unconscious vision and imaginary blindness

  • David Robson
  • BBC Future

Photo author, Getty

Photo caption,

Patients with pseudo blindness cannot consciously perceive visual images1116, scientists believe People who have lost their sight sometimes retain the ability to see – with the help of a supernatural subconscious feeling. It sheds light on the hidden depths of human consciousness, says correspondent

BBC Future .

When Daniel first appeared at London National Hospital, ophthalmologist Michael Sanders hardly imagined that this man would change the way we think about the human mind.

Daniel on the doorstep declared that he was half blind. He had healthy eyes, but the operation damaged the part of his brain responsible for vision.

Daniel stopped seeing everything to the left of his nose. Now he saw as if he were trying to see the world through a half-curtained window.

However, Sanders began checking his eyesight and noticed something strange.

Why do we need consciousness?

Daniel was still able, with his hand outstretched, to touch the doctor’s hand, even if he fell into his “blind spot” – as if he was being moved by a “second sight” acting outside of consciousness.

Sanders became interested in the patient and referred him to psychologists Elizabeth Warrington and Lawrence Weiskrantz, who performed several tests and confirmed the ophthalmologist’s guess.

Photo author, iStock

Photo caption,

The world of human visual sensations appears as if in semi-darkness

Psychologists placed a screen to the left of Daniel and asked him to point to a circle that appeared in different parts of the screen.

Daniel was sure he couldn’t see anything, but Weiskrantz asked him to “make a guess.”

To everyone’s surprise, the subject was almost always right.

Weiskrantz and Warrington also showed Daniel the lines – then he was asked to determine which line appeared on the screen, horizontal or vertical.

Daniel was again sure that nothing would appear in front of his eyes, however, this time he gave the correct answer 80% of the time, that is, much more often than if he just spoke at random.

It is obvious that, despite his blindness, Daniel’s healthy eyes continued to see the world and transmit information about what he saw to the unconscious, which guided the young man’s behavior.

In 1974, Weiskrantz published a report using the new term “pseudo-blindness” to describe this fragmented state of consciousness.per.).

“Of course, some were skeptical, but the term stuck and became a widely accepted phenomenon,” says Weiskrantz.

Over the next decades, this state helped answer some fundamental questions about the human mind.

How many decisions does our unconscious actually make for us (even if we harbor the illusion of control)?

And if consciousness is not required to guide our actions, then what is its purpose?

Why has this vibrant inner life developed in us, if in reality we are like zombies acting unconsciously?

“Examples like these give us the opportunity to see areas of the brain that would normally go unnoticed,” says Marco Tamietto of Tilburg University.“They offer a glimpse of brain functions that are usually difficult to observe because they don’t manifest themselves.”

Unraveling Consciousness

Consciousness is so deeply connected to everything we do that many scientists used to think it was impossible to study.

How can we choose from the rich fabric of our mind that single thread that gives us a vivid experience of being in the world, living feelings and experiences given by the outside world? How can we study consciousness in isolation from everything that surrounds it?

Example of Daniel ( by the way, the name of the young man in this article has been changed; in the scientific literature he is simply referred to as “DB”) served as the first clue.

“You should study something that is as close to consciousness as possible, but does not depend on subjective experience,” says Christopher Allen of Cardiff University. “For example, pseudo-blindness. With this, the subject still perceives (information) but does not know about perception. ”

First of all, the scientists decided to find out what exactly patients with pseudo-blindness who cannot consciously perceive visual images can see. The results were impressive.It is especially interesting that such people can read emotions: if you show them a face, they will determine the expression of joy and sadness, anger and surprise. Moreover, they will even start unconsciously copying facial expressions.

“Even though they couldn’t notice anything on a conscious level, we recorded the change in emotions, their synchronization with the images in the blind spot,” says Tamietto, who has worked extensively with Weiskranz.

In addition to copying emotions, they also reproduced physiological signs of stress when shown a frightened face.

Photo author, Getty

Photo caption,

What part of the world do we actually see, and how much our actions are determined by the subconscious?

“In the future, we are planning to try to teach them to recognize the reaction of the body,” says Tamietto. Then people would understand that they are in danger.

“By the reaction of the body, they could understand what is happening around them – something interesting or a problematic situation.”

In 2008, the team of Tamietto and Weiskranz conducted another – the most brutal –

experiment on a patient with pseudo-blindness.

Unlike Daniel, the new test subject did not see anything at all and in ordinary life moved with the aid of a cane.

The team of scientists took the cane from him and then took the patient into a hallway full of furniture that could easily trip over.

Subject was to walk along a corridor from one end to the other. “He said he couldn’t see anything; nevertheless, he got the job done on the first try,” Tamietto says.

It is important to note that the subject not only claimed that he did not know that he was seeing something; he was also unaware that he was bypassing objects.He insisted that he was just walking right down the hallway.

According to Beatrice de Gelder, who led the study, the patient “found it difficult to explain or even describe his actions.”

Only on very rare occasions are people with pseudo blindness able to come close to understanding what they see.

For example, one of the subjects was able to discern movement in fast, contrasting films; he described what he saw as “a black shadow moving against a completely black background”, “a feeling of knowing” that there was something there.

However, even in this case, he could not describe the picture, that is, his experience was almost completely devoid of everything that we usually associate with vision.

“There is still no consensus on whether this evidence reflects real visual experience,” says Robert Kentridge of the University of Durham.

Temporary blindness

Of all the questions posed by such studies, the main question remains “why?” What makes the conscious and unconscious disconnect so much?

Tellingly, all subjects with pseudo-blindness suffered from the same area of ​​the brain – the so-called V1 zone, the primary visual cortex located in the back of the brain.

Hence the assumption: it is this area that is responsible for sending the stream of images into our consciousness.

To test their assumptions, the scientists used non-invasive brain stimulation. With its help, it is possible to “switch off” various areas of the brain, thus causing temporary pseudo-blindness in sighted subjects.

Photo author, iStock

Photo caption,

People with pseudo-blindness cannot see what is in front of them, but can feel their surroundings

Wanting to know how pseudo-blindness feels, I took part in one of the experiments at Allen’s laboratory in Cardiff, UK ( the video recorded during the procedure can be viewed

in the original article in English on the website

BBC Future).

The method used by scientists is called transcranial magnetic stimulation (TMS): a strong magnetic field affects the neural activity inside the skull.

“The advantage is that no one needs to open the skull in order to recreate the behavioral characteristics of pseudo-blindness,” Allen explained to me before the procedure.

The experiment began with Allen placing a magnet at the back of my head, above V1. Then, for short periods of time, each time with increasing strength, he began to create a magnetic field.

At first I felt only a slight tapping (the effect of a magnetic field on my skin), but then I noticed that a rapidly fading black line crossed the picture in front of my eyes – something similar appears on the screen when you turn off an old TV.

This lasted less than a second; although I experienced some shock, I quickly got used to this feeling.

After Allen adjusted the power, I sat down in front of the computer, and arrows began to flash in front of me.

I had to say which arrow was shown on the screen for a split second – left or right. Sometimes images were synchronized with TMS signals causing temporary blindness.

Just like Daniel in the first experiments, I didn’t see anything and thought I was answering at random.

However, when we were done, Allen said that I had more correct answers than I could have given them randomly. This means that during the experiment it turned out to cause pseudo-blindness.

Through this research, Allen found as yet unconfirmed evidence that visual information travels through the lateral geniculate body, located deep in the center of the brain.

This is a detour around the V1 zone, which allows unconscious processing of information in the zones responsible for emotion and movement.

In the future, scientists may even understand how the brain creates visual consciousness itself, and why the V1 zone is so important. According to one version, consciousness is based on connections between many areas of the brain, and V1 can act as a node that organizes translation.

Exploring the very experience of pseudo-blindness can also provide clues about the power of the unconscious.

Attention Paradox

Imagine you are in a puppet show. You have been blindfolded, with invisible threads tied to your limbs.

The invisible puppeteer very quickly pulls one string, then the other, forcing you to perform a complex dance. Viewers feel like you are in complete control of your actions, but in reality you have no idea what you just did.

When a person with pseudo-blindness bypasses obstacles, this is a kind of puppet show, in which the unconscious plays the role of a puppeteer.

“Consciousness is not everything,” Tamietto says. “Very often we think that we have decided something, but in fact, our brain made a decision for us even earlier, in many ways, in many contexts.”

Juha Silvanto of the University of Westminster agrees: “Consciousness just brings together all incoming information, but the fact that the subconscious can direct our behavior means that complex processing takes place without our participation.”

Photo author, iStock

Photo caption,

Carriers of pseudo-blindness open new ways of knowing the world, studying their own unconscious

In fact, even some philosophers wondered if we are not a little more complex creatures than zombies, which are ready for action are prompted mainly by unconscious impulses.

This, in turn, casts doubt on some well-established assumptions about the very nature of consciousness and its purpose.

In the end, there is no certainty that animals have the same rich inner world as we do, so for some reason it had to appear [with the advent of Homo sapiens].

Psychologists used to think we had some kind of “spotlight”; vision translates it to an object, and then the object enters consciousness.

Thus, our increased involvement helps to highlight the most important parts of the overall picture and gives us the opportunity to respond.

Only Robert Kentridge of Durham University has evidence that this may not be the case at all.

His guess was born during a conversation with a test subject suffering from pseudo-blindness.The dialogue took place in between some basic tests, during which different images are shown in different zones of the blind spot.

Subject said that, in his opinion, he would have done better if he had been told in advance exactly where the next image would appear.

“It seemed very strange,” says Kentridge. Because pseudo-blind patients are unaware of what is falling into the blind spot, they cannot focus their attention on these objects.

“As if you were trying to direct your attention to the back of your head. You shouldn’t be able to do that,” he says.

However, he was happy to play along with the patient and come up with another experiment in which the subject would be given a clue as to where the image might appear.

The results were paradoxical: despite the fact that the participant was still unable to see anything, his subconscious mind seemed to start working faster.

In other words, the subject did “pay attention” even though he did not know what it was.

Therefore, Kentridge believes that we need to rethink our understanding of consciousness and attention. In his opinion, there is no center of attention that enhances perception, but there is consciousness that has evolved to enhance memory.

Consciousness gathers different pieces of information into a single picture that is easier to remember. “You need to encode what is happening in the world into one package,” he says.

These are just a few of the many clues that will one day help unravel the mysteries of human consciousness.

Sorry, Daniel will not be taking part in further experiments. “He passed away last November, but he was willing to be involved in research for years,” Weiskrantz tells me.

Thus, he showed the way to others and led us through the darkest secrets of the human mind.

Retinoblastoma (Brief information)

Retinoblastoma is an eye cancer. In our text, you will receive important information about what kind of disease it is, how often it occurs, why a child can get it, what the symptoms are, how the diagnosis is made, how children are treated and what are their chances of being cured of this form of cancer.

author: Maria Yiallouros, erstellt am: 2016/04/04,
editor: Dr. Natalie Kharina-Welke, Permission to print: Dr. med. Christine Jurklies; Dr. med. Petra Temming, Translator: Dr. Maria Schneider, last modified: 2021/01/26
doi: 10.1591 / poh.retino-patinfo.kurz.1.20120611

What is retinoblastoma?

Retinoblastoma is a rare type of eye cancer. The tumor grows in the retina of the eye (the medical term for retina is retina) and it is almost always found only in children.This disease has a hereditary and non-hereditary form. If retinoblastoma is hereditary, then family members have a predisposition to the fact that one of them may get sick. If retinoblastoma is not hereditary, then eye cancer occurs spontaneously, that is, the cells of the retina of the eye begin to change by themselves.

Retinoblastoma can affect one eye, or both eyes. Most often, it grows in only one eye (experts call this unilateral retinoblastoma, or unilateral tumor).In about one third of children, the tumor begins to grow simultaneously in both eyes (experts call it bilateral retinoblastoma, or bilateral tumor). If cancer appears in both eyes at once, then this almost always indicates hereditary retinoblastoma. Unilateral retinoblastomas are usually not hereditary. The tumor can grow in one area of ​​the eye (in this case, doctors call it unifocal), or simultaneously in several areas (then doctors speak of a multifocal tumor).

Retinoblastomas usually grow quickly. They can appear inside the eyeball. From there, they grow into the orbit and travel along the optic nerve [optic nerve] to the brain, and cancer cells enter the central nervous system [CNS]. If the disease is at an advanced stage, then cancer cells through the blood and / or lymphatic pathways enter other organs. If left untreated, the disease is almost always fatal. Only in extremely rare cases (in 1-2% of children) the tumor spontaneously disappears by itself.In this case, experts talk about spontaneous regression.

How common is retinoblastoma in children?

Of all types of intraocular cancer, retinoblastoma is the most common cancer in children. In Germany, about 40 children and adolescents under the age of 15 fall ill with retinoblastoma every year. In other words, one out of 18,000 newborns every year develops retinoblastoma. But in general, this type of cancer is rare. According to the Children’s Cancer Register (St.Mainz) retinoblastoma accounts for about 2% of all cancers in children and adolescents.

As a rule, retinoblastoma occurs in infants and young children, that is, almost always – under the age of 5 years. Almost 80% of cases are children under the age of four. Retinoblastoma is extremely rare in children over six years of age.

Why do children get retinoblastoma?

Retinoblastomas appear when two genetic [genetic] changes (two mutations) occur in the progenitor cells of the retina, the so-called retinoblasts.These changes (mutations) can spontaneously appear in the cells of the retina themselves. But mutations can also be found already in the germ cells [germ cells], and therefore in all the cells of the body; then such mutations are inherited, that is, they are congenital.

In the majority of patients – about 60% of all children – retinoblastomas are not hereditary. This means that changes appeared only in a sick child (experts call such mutations the term “sporadic”), and the mutation is isolated only in tumor cells.But 40% of retinoblastomas are congenital. In about a quarter of these cases (that is, from 10 to 15% of all patients), retinoblastoma in the family was already known. When it is known that someone has already suffered from this type of cancer in the family, experts talk about familial retinoblastoma. Other congenital retinoblastomas appear for the first time in children.

Regardless of whether retinoblastoma is hereditary or not, specialists always find genetic changes in the so-called retinoblastoma gene [retinoblastoma gene], which is located on chromosome 13 [chromosome].Since in humans each cell contains a double set of chromosomes, this means that the retinoblastoma gene is also duplicated (each cell has two so-called alleles [allele] of the retinoblastoma gene). The tumor begins to grow only when there are changes in both alleles.

For more information on the genetic classification of retinoblastomas, how often they appear and how they occur, see the section “The genetics of retinoblastoma / How is the disease inherited?”

What are the symptoms of the disease?

While retinoblastoma is very small, children usually do not complain about anything.For a long time, the disease does not manifest itself in any way, children do not have any symptoms. The first complaints appear when the swelling becomes larger, or it begins to grow into other parts of the eye. The child begins to lose sight, sometimes to the point of complete blindness. The visual acuity of both eyes becomes different and therefore strabismus may appear in children (occurs in about 25 to 30% of patients).

The most common first symptom, according to which about one third of children are diagnosed with retinoblastoma, is a white glow of the pupil under certain lighting conditions (in the language of specialists, this symptom is called leukocoria).For example, in bright light from a camera flash, the healthy pupil becomes red or black, and the diseased pupil develops a white reflex. Such a white pupil is called a “cat’s eye”, and the very effect of a “cat’s eye” suggests that the tumor has already grown behind the lens. Less commonly, it happens that a child’s eye hurts, reddens or swells when intraocular pressure rises.

Anxiety symptoms in children are:

  • when the pupil (or both pupils) turns whitish-yellow (leukocoria)
  • the child begins to squint or vision deteriorates / visual acuity
  • redness or swelling of the eyes, eyes start to hurt

If a child develops one or more of the listed symptoms at once, this does not mean that he or she is ill with retinoblastoma, or some other type of cancer.Some of these symptoms appear for completely harmless reasons and have nothing to do with cancer. However, we recommend that you see your doctor as soon as possible and find out the exact cause. If it really is retinoblastoma (or some other malignant disease), then a timely diagnosis is the best condition for a good treatment result.

Children from families with an increased risk of hereditary disease should have regular eye examinations, even if they have no symptoms or complain about anything.Only then can a specialist diagnose retinoblastoma at an early stage and the child will be treated on time.

How is retinoblastoma diagnosed?

If the pediatrician (or other specialist) suspects retinoblastoma from the child’s medical history (history) and according to the results of external examination [external examination], the doctor will refer the child to a clinic that specializes in this form of oncology (ophthalmological or children’s cancer center).

If retinoblastoma is suspected, different tests should be performed. First, the diagnosis must be confirmed. Secondly, it is necessary to find out what specific form of retinoblastoma the child fell ill with (hereditary or non-hereditary), and how much the disease had time to disperse throughout the body.

Ophthalmoscopy is the most important test to confirm the diagnosis. If retinoblastoma is indeed confirmed, then more research is needed to understand exactly how much.the disease has spread throughout the body. Such important tests are ultrasound (ultrasound) and MRI (magnetic resonance imaging). Additionally, the child is examined by a pediatrician.

In rare cases, for example, when a child has a pronounced late stage of the disease and / or soon needs to start chemotherapy, specialists may perform other additional tests, for example, chest X-ray, analysis of cerebrospinal fluid (lumbar puncture), bone brain (bone marrow puncture) and / or examination of the child’s bones (scintigraphy of the bones of the skeleton).

All diagnostics are performed not only for a sick child. Since the patient may have a congenital form of retinoblastoma, the ophthalmologist checks his brothers, sisters and parents. Also, the whole family undergoes a molecular genetic blood test (genetic diagnosis) to assess the hereditary situation.

When all the necessary studies and analyzes are done, a team of specialists together with you decides which treatment tactics will be most effective for your child.

How is retinoblastoma treated?

Treatments for children with retinoblastoma include surgery, radiation (brachytherapy or percutaneous radiation therapy), cryotherapy, laser therapy, and chemotherapy.

What specific method of treatment specialists will stop at depends on whether the tumor has grown in one eye, or in both, how much the disease has spread throughout the body at the time of diagnosis (stage of the disease), and whether it can be expected that after therapy, vision can still remain in one eye, or both.Also, when drawing up a treatment plan, the child’s age is taken into account.

The goal of any treatment is to completely kill, or more accurately remove, the tumor, which means complete recovery from cancer. Therefore, the basic principle is that keeping a child alive is more important than keeping eyesight.

In principle, two treatment tactics are possible:

  • surgical removal of the tumor together with the eye (in the language of specialists this is called enucleation)
  • Treatments with radiation therapy, laser therapy, cryotherapy and / or chemotherapy that save the eye.

It is possible to cure a child and save an eye at the same time only if the diagnosis of retinoblastoma was made in a timely manner, that is, at an early stage of the disease. The goal of such treatment is to completely neutralize the tumor and at the same time preserve vision without risking life. If the disease is at a later stage, then, as a rule, removal of the eye is inevitable. If metastases were found, then in addition to the operation, chemotherapy and / or radiation therapy should also be carried out.

How children with unilateral retinoblastoma are treated

If the child has unilateral retinoblastoma, then removal of the diseased eye (enucleation) is the most reliable and most justified method of treatment. Because the child has a second fully working eye and it is possible to refuse other types of treatment that have certain risks. If retinoblastoma is not hereditary, then this is where the treatment ends and the child recovers completely.

If the tumor is small, then in some cases a treatment is possible, which will preserve the eyeball (first of all, this is a local treatment, the so-called brachytherapy). But this type of treatment is justified only if it is possible not only to cope with the tumor, but after its completion, vision can still be preserved. It is not yet known how long the effectiveness of this method of treatment will be (that is, whether the survival rates of patients will worsen in the long term).

But it must be said that unilateral retinoblastomas, as a rule, are found very late, that is, already at advanced stages. By this time, the diseased eye is usually already blind. Therefore, when it is removed, it does not mean that the child will become worse in seeing or worse to orientate.

If the tumor can be completely removed by surgery, then no additional treatment is needed after the operation. If the analysis of the tumor tissue (histological analysis) from the removed eye shows that the retinoblastoma was very extensive, or it has already gone beyond the eye, then after removal (enucleation) the child receives chemotherapy courses.Chemotherapy is needed to kill tumor cells, possibly remaining in the body, or to destroy the smallest metastases. In extremely rare cases, additional percutaneous radiation therapy is performed.

How children with bilateral retinoblastoma are treated

If your child has bilateral retinoblastoma, doctors will try to find an individual combination of the available treatments. Their goal is not only to completely control the tumor, but also to simultaneously preserve vision in at least one eye.

Therefore, treatment starts with local therapy . Isolated small retinoblastomas can be reliably destroyed with local treatments such as laser coagulation, cryotherapy, or brachytherapy. But it must be said that often these types of treatments need to be performed several times.

If the tumor is too large for these methods, then in some cases courses of chemotherapy are first prescribed to reduce the size / volume of the tumor .After that, they move on to local therapy (that is, to laser therapy, cryotherapy or brachytherapy).

It often happens that in one of the eyes the retinoblastoma has grown so extensively that there is no point in trying to save the eyeball. Therefore, specialists completely remove the eyeball ( enucleation ).

Sometimes – in cases where chemotherapy is required to treat a less diseased eye – enucleation of the more affected eyeball may be delayed.As a result of chemotherapy, the tumor can go away and shrink so strongly (in the language of specialists, this is called tumor regression) that it will still be possible to save the eyeball. But if the worst eye is already blind, or the tumor has grown into the anterior part of the eye (doctors talk about tumor infiltration), or the tumor has grown into the optic nerve, then only enucleation remains. There is no other alternative.

If in the second eye (initially less affected by the disease) the tumor continues to grow (that is, the tumor began to grow into the optic nerve or into the choroid; there are tumor screenings in the vitreous body), then the only treatment that can save the eyeball is percutaneous irradiation .But it is done only if the function of vision has not yet been lost. If this is not the case, then it is necessary to remove the second eye, so as not to endanger the life of the child.

Since the risks of complications after courses of modern chemotherapy are lower than after irradiation, today doctors tend to refuse percutaneous radiation therapy [percutaneous radiation therapy] as much as possible, especially in children of the first year of life. But I must say that the effectiveness of percutaneous irradiation remains indisputable, since retinoblastomas are very sensitive to irradiation.

What are the new approaches to retinoblastoma treatment?

To avoid the need to remove the eyeball or conduct radiation therapy, as well as, if possible, reduce or even avoid complications after intravenous chemotherapy (and it acts systemically, that is, on the entire body of the child), recently specialists have been developing and testing new methods of treatment.

One of the most promising treatments is the so-called intra-arterial chemotherapy (you can also find another term intra-arterial chemotherapy ).This means that the cytostatic and (for example, melphalan) are deliberately injected into the eye through the ophthalmic artery. To do this, a catheter is inserted through the groin into the femoral artery, moves towards the heart and is brought to the right place, that is, to the ophthalmic artery of the diseased eye. Through a catheter, the drug is injected directly into the ophthalmic artery and from there diverges through the vascular system that supply blood to the eyes, including through the vessels of the tumor, that is, retinoblastoma.

This type of treatment is still experimental.They work with him in several clinics and only with a certain group of patients, for example, if the disease does not respond to standard treatment. In some cases, it is performed as an initial treatment (primary therapy). So far, the results have been good. But it is not known exactly how long the effect will be, that is, how long this local treatment allows the tumor to be controlled. Also, all potential late complications and consequences have not yet been fully explored.

What protocols and registries are used to treat children?

In order to choose the most optimal treatment method for each specific case, which is recommended for each risk group (in the language of specialists – risk-adapted treatment), there must be a base that is based on reliable statistical data.But retinoblastoma is an extremely rare disease (in Germany and Austria, about 4 children fall ill every year). Therefore, to date, little data has been accumulated on this disease.

Therefore, unlike other forms of cancer that occur in children and adolescents, there is no single standard protocol for the treatment of retinoblastoma, which in Germany is called therapy optimization studies. (German protocols, or therapy optimization studies, are clinical studies and are strictly controlled.They are used to treat children and at the same time investigate a specific form of cancer).

It is for this reason that clinical register RB-Registry was opened in 2013. This registry will collect data on the epidemiology [epidemiology] of retinoblastoma and how the disease progresses for several years. The goal is to gather more information about this form of cancer and how different types of therapies respond to treatment.

This registry accepts all children and adolescents from Germany and Austria up to 18 years of age who first develop retinoblastoma and / or have a germline mutation in the RB1 gene (germline mutation [germline]) and have not yet received any treatment.The central research office is located at the Essen University Hospital. Head – Ph.D. Petra Temming.

In addition, patients with hereditary retinoblastoma have the opportunity to be included in the European research protocol that investigates the causes of secondary tumors after retinoblastoma has been successfully treated (research protocol “Screening of secondary tumors in children with hereditary retinoblastoma” ). As part of this screening study, children undergo an MRI of the head once a year.The conditions under which children are taken into this protocol: hereditary form of retinoblastoma, children during treatment received radiation therapy, the child’s age is between 8 and 18 years.

A research protocol on the effectiveness of chemotherapy is currently being planned. But he will be able to start only when funding is received.

What are the chances of recovering from retinoblastoma?

Today, thanks to modern approaches in diagnosis and treatment, more than 95% of children with retinoblastoma are cured.Children with unilateral retinoblastoma are left with one healthy eye with no visual impairment and can lead a normal life. Most children with bilateral retinoblastoma also have at least one eye that can see enough.

For each individual child, the prognosis depends mainly on the stage of the disease at which the diagnosis of retinoblastoma was made, and whether the retinoblastoma is congenital (hereditary retinoblastoma).

If at the time of diagnosis the tumor has not spread beyond the eye, or beyond the two eyes (experts in this case speak of intraocular retinoblastoma), then the disease responds better to treatment than advanced retinoblastomas.Therefore, in principle, they have a more favorable prognosis.

Children with hereditary retinoblastoma generally have a worse prognosis than children with non-hereditary retinoblastoma. This is due to the fact that regardless of the treatment, congenital forms of the disease have a genetic [genetic] predisposition to the fact that in the future the child will develop another cancer (secondary malignant tumor). This can be, for example, osteosarcoma, or soft tissue sarcomas.This risk is further increased if, during the treatment of retinoblastoma, the child was given radiation to the eyeball.

In about 5% of children with congenital retinoblastoma, which was initially unilateral, retinoblastoma also grows in the other eye within a year and a half after the first illness.


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  4. Shields CL, Shields JA: Retinoblastoma management: advances in enucleation, intravenous chemoreduction, and intra-arterial chemotherapy.Current opinion in ophthalmology 2010, 21: 203 [PMID: 20224400]


  5. Lohmann D: Die Genetik des Retinoblastoms. WIR Informationsschrift der Aktion für krebskranke Kinder e.V. (Bonn) 2007, 1:31 [URI: http://www.kinderkrebsstiftung.de/ fileadmin / KKS / files / zeitschriftWIR / 2007_1 / WIR_01_07_S31-33.pdf]


  6. Jurklies C: Das Retinoblastom – Diagnose und Therapie. WIR Informationsschrift der Aktion für krebskranke Kinder e.V. (Bonn) 2007, 1:26 [URI: http: //www.kinderkrebsstiftung.de / fileadmin / KKS / files / zeitschriftWIR / 2007_1 / WIR_01_07_S26-31.pdf]


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  8. Gutjahr P: Retinoblastome, in: Gutjahr P (Hrsg.): Krebs bei Kindern und Jugendlichen. Deutscher Ärzte-Verlag Köln 5. Aufl. 2004, 499 [ISBN: 3769104285]


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Retinoblastoma (brief information) – Retinoblastom (PDF-Datei)


90,000 The doctor who saved 86 people after the methyl: “Most continued to drink”

Raido Paasma, the head of the anesthesia and intensive care service at Pärnu Hospital, and the entire hospital staff made great efforts to save the lives and health of our compatriots. 12 years later, he even defended his thesis on clinical studies of mass methanol poisoning …

It seems that when fate in the face of doctors or luck gives you a second chance at life, there is only one option – to cling to it and not repeat past mistakes.As life shows, people do not always appreciate it. Many people are interested in the fate of Irkutsk residents who survived the Hawthorn poisoning. Their diagnosed “colleagues” – residents of the Estonian city of Pärnu, who were poisoned with methanol back in 2001 – can hardly set a good example.

– Raido, to prepare your dissertation you had to observe people who then survived. How was their fate?

– After treatment in the hospital, 86 people recovered then. At the same time, some of them still have problems with vision and neurology.Six years after the incident, we called them for follow-up observation. And here’s what it turned out: more than 30 people have already died during this time. Approximately the same number came for a second appointment … We could not reach the rest: we sent them letters, tried to get through, but they did not respond. And we did not insist, since this is a voluntary matter. We talked with those victims who reached us and examined them. And, unfortunately, it turned out that about 70% of them still drank alcohol.

– And those people who became disabled did not change their way of life? What injuries were they discharged with?

– Someone went blind, someone lost their memory, could no longer walk. Some of them were constantly shaking hands and feet. These people also continued to drink because they had lost the purpose of life.

– You say that more than thirty people have died in six years. What are the causes of death?

– The main one is still the same – excessive alcohol consumption.This led to various injuries, cardiovascular diseases, pneumonia …

– It turns out that methanol was not needed either … Returning to our main topic – how does methanol affect the body? How easy is it to deal with such poisoning?

– The fact is that methanol itself is not toxic. But it is metabolized, in simple terms, begins to have a toxic effect on the body within 12-24 hours after ingestion.And here the difference between humans and animals is interesting. Animals have a substance in their bodies – folic acid, it neutralizes methanol. We also contain it, but in a very small amount, so it does not help us. Methanol poisoning is very difficult to diagnose. After all, the time from consumption to the first clinical symptoms can be quite long. And it can be even longer if people drink normal vodka along with methanol or after it. Symptoms will appear when alcohol is excreted from the body.

– That is, high-quality alcohol does not neutralize the effect of methanol? This is the most common version in Russia – that in order not to get poisoned with methanol, you just need to drink vodka. So this is not a panacea?

– Ethyl alcohol really neutralizes methyl alcohol. But only for a while. Look, the time of the toxic decomposition of methanol is 72–90 hours. To counteract, you must keep the concentration of ethanol in the blood at least 1 ppm for three to four days.As long as the blood contains this amount of pure alcohol, methyl alcohol may not even begin to metabolize. But it is very difficult to fulfill this condition, people will simply want to sleep. Therefore, it is impossible to be treated like this.

– Is there really no way to help yourself? Now a person realized that he drank methanol, what should he do? Maybe you should induce vomiting, eat something? ..

– The fact is that immediately after drinking a person will not understand that he has drunk methanol. Symptoms will appear in 10-12 hours, when you cannot help yourself: methanol has been metabolized and has begun to destroy the body.There is no point in amateur performance – you need to immediately call a doctor. With us, it turns out like this: people read somewhere in the newspapers that you can just drink vodka and be cured. They get drunk, fall asleep, and wake up already blind. Because during this time, ethanol was eliminated and ceased to neutralize the effect of the poison. This happens very often. And this is very scary.

– How will the poisoned people be rescued in the hospital? Is current treatment different from what it was 15 years ago?

– In 2001, our main difficulty was to diagnose methanol poisoning.The first admissions did not have clear clinical symptoms. Of course, when there were a lot of calls and the diagnosis was made, we started treating them with ethanol. Patients received a hemodialysis procedure – blood purification. There were so many victims that we immediately sent them to other hospitals – to Tallinn, Tartu …

There are two antidotes for methanol poisoning. The first is ethanol, but I have already said that it must be constantly maintained in the body. Now there is another one: fomepizole. It’s much easier with him.Therefore, it is enough to give it twice a day, with an interval of 12 hours. And you don’t need to monitor his level. You can be sure that the methanol is not metabolized further. This is the essential difference between the two drugs. Ethanol is, of course, much cheaper. But I believe that if possible, hospitals need to have fomepizole.

– Was it not there in 2001?

– He just came out, he hasn’t been in Estonia yet.

Dr. Paasma (pictured left) saved the lives of Estonians after being poisoned in 2001.Photo: From personal archive

– People who drank poisoned vodka – who were they? Those who poisoned the Hawthorn in Irkutsk still belonged to a certain stratum of the population. And who in Estonia bought clandestine alcohol?

– All kinds of people. These are the poor, and ordinary workers, and young people who came to the party: alcohol was over, someone knew a place where you can buy, went, bought, drank … People bought that vodka just on the day when everyone received their salaries and pensions.And they did it from people who were regular customers.

– But why exactly illegal alcohol? Just because of the price?

– As I learned from the conversation with the victims, there were three factors. The main thing, of course, is the price. Another group explained the act by the fact that they know the seller well, “work” with him for years, and he always sold them a worthy product. The third reason: it was possible to buy alcohol in stores only until 22.00. If you need alcohol at a later time, you will go elsewhere to look for it …

– How was a similar product sold in Pärnu? Did you have to come to someone’s home or say a certain password in the store, and they will get you from under the counter?

– Good question, but to the wrong person.I can honestly say I have never bought anything like this. But I know that in 2001, most of the merchants were selling alcohol right at home. There were also many buyers from the villages. And in order to reach this category of customers, the sellers drove around the farm by car. Most often it was again on the days of salaries and pensions. Those who needed alcohol went out to them and bought. How it is happening now, I cannot say. But the problem with people being poisoned with methanol is still relevant.

The poisoning scenarios in Irkutsk and Pärnu are frighteningly similar.And here and there, the victims were people who are not indifferent to alcohol of untested quality. In Russia, unlike Estonia, alcohol is more than available in stores. Almost everyone can afford the same vodka or port. Another thing is that the cheapest swill will also affect the body not in the best way. However, it will not bring it to the cemetery. And, despite this, the Russian people continue to drink tinctures from pharmacies, colognes, “hawthorns” …

It is not a fact that tragedy is the last action of this fatal performance.As long as there are people who are ready to drink booze of unknown origin, there will always be those who want to make money on it. Even at the cost of buyers’ lives.

Read the materials “Confessions of a methanol poisoner: those involved in the death of 68 people live happily”

You can distinguish methyl alcohol from ethyl alcohol using a wire

90,000 If your animal’s eyes are clouded

Clouding of the eye in cats, dogs and other pets mainly occurs due to damage to the cornea or lens of the eye:

  1. When the cornea is damaged, the surface of the eye becomes cloudy, acquiring a whitish or blue tint, and also often loses its luster;
  2. When the lens is damaged, the cornea (the transparent membrane of the eye) remains transparent, and the opacity is located in the pupil area (in bright light, the opacity narrows, in dim light it expands).

Corneal opacity occurs in any of its diseases and is associated with the accumulation of fluid, pus, crystals of cholesterol and calcium in its tissues, the germination of blood vessels and the formation of scars (leucorrhoea).

  1. Keratitis is an inflammation of the cornea. In this disease, vision is reduced or completely lost. It occurs with general infectious diseases (infectious hepatitis), poisoning and intoxication, with acute conjunctivitis, the inflammatory process can quickly move to the cornea.With keratitis, as with any other disease of the cornea, urgent qualified veterinary care is needed;
  2. Glaucoma – increased intraocular pressure. Corneal opacity in most cases occurs with a sharp increase in intraocular pressure (acute attack of glaucoma). To preserve vision, the animal needs immediate veterinary assistance, since the irreversible loss of vision due to atrophy of the optic nerve occurs 2-4 days after the increase in pressure;
  3. Corneal erosions and ulcers – defects of the cornea of ​​varying depth and size. Corneal erosions and ulcers occur in trauma, viral and bacterial infections, chlamydia, eye burns, purulent conjunctivitis, allergies, dry eye syndrome, glaucoma. In addition to clouding of the eye, reddening of the eye and squinting of the eyelids is noted with erosion and corneal ulcers. Treatment of erosions and corneal ulcers is always complex, and includes antibacterial, immunostimulating and corneoprotective drugs;
  4. Corneal degeneration – occurs as a result of local metabolic disorders in the cornea. Clouding occurs due to the deposition of opaque crystals of cholesterol, amyloid or calcium in the cornea. In some cases, corneal degeneration is accompanied by ulceration of the corneal surface. For the treatment of corneal degeneration, both medical and microsurgical methods are used;
  5. Scars (leucorrhoea) of the cornea – corneal opacities remaining at the site of injuries, ulcers and burns of the cornea. With the timely appointment of treatment, the corneal leucorrhoea partially or completely resolves.

If an animal’s eyes become clouded, then you need to know the following. First of all, the pupil itself cannot become cloudy, since it is a hole in the iris of the eye. The crystalline lens (transparent lens) located directly behind the pupil becomes cloudy. The clouding of the lens occurs due to the accumulation of excess moisture in it, or vice versa, when the lens dries out (sclerosis).

Cataract – clouding of the lens of the eye. With partial lens opacity, vision deteriorates, and with complete (mature cataract), the animal completely loses its vision. The main cause of cataract is the elderly (over 7 years) age of the animal. Blurred eyes are common in dogs. For example, dog breeds such as the Poodle, English and American Cocker Spaniel have a breed predisposition to developing cataracts even at a young age. There are cases of congenital cataracts. At the initial stages of cataract, the animal is prescribed eye drops to stop the disease. In the case of mature cataracts and loss of vision, surgical removal of the cataract and implantation of an artificial lens are performed.

Clouding of an eye in a cat, dog or other pet is always accompanied by a decrease or complete loss of vision. Restoration of vision directly depends on the time of contacting a specialist, an accurate diagnosis and competent prescription of medications.

If your cat has cloudy eyes, clouded eyes in a dog or other pet, it is best to immediately seek help from a veterinarian. Consultation with a specialist in most cases will allow you to overcome the disease at an early stage, to cure the eyes of a pet.

If your pet has cloudy eyes, it could mean that your pet is seriously ill

Experienced doctors of the network of veterinary clinics “Doctor Aibolit” will help you avoid the consequences of this disease. In the “Contacts” section, you can choose the nearest clinic “Doctor Aibolit”, or order a veterinarian’s home visit.

90,000 What does a sense of humor depend on?

In fact, it all starts with a simple question: “Why do we need humor?” It has different functions – for example, gender.For example, when a man jokes in the company of a woman, he wants to be liked.

My colleagues and I examined the sense of humor in terms of intelligence. I’ll make a reservation right away that the connection between education and humor is not so strong. Very smart people may not know how to joke. But we made a comparison: how people, after watching funny videos, solve mathematical problems – with an obvious algorithm and the so-called creative ones, where there is no specific solution scheme. As a result, all subjects were able to solve creative problems faster with a non-standard approach.The principle of creating a joke and the principle of finding a solution are similar. In any complex mathematical problem, the solution lies in the form of an unexpected combination of moves, and in a joke – in the form of an unexpected combination of words. It turns out that, in a sense, people with developed creative thinking are more successful jokers.

There is another version. In fact, the human smile that accompanies a joke is a displaced unrealized aggression, even outwardly resembling a grin. If we smile at a stray dog ​​on the street, it is unlikely that it will be regarded as a manifestation of friendliness.The word “humor” appeared only at the end of the 18th century, and before that time the word “ridicule” was used even in English. In French it means “funny, ridiculous”, and in English it means “ridicule”. Accordingly, humor was considered a sudden manifestation of a sense of one’s own superiority, aggressive dominance. Hence the banana peel jokes: he, a fool, slipped and fell, and I, well done, stand over it all and watch.

Humor is a common human acquisition, but each nation has its own structure.There is such a separate phenomenon as British humor: it is built on a subtle combination of words, on a linguistic game. This is how almost any joke works from a verbal point of view – a person pronounces aloud a sentence with an unexpected meaning, often formed due to ambiguity. Here’s an example: “At the Biathlon World Championships, the German national team won Poland.” There are two meanings here: according to the first, the German national team won medals, and according to the second, the Germans with rifles on skis conquered Poland.Such a transition from one meaning to another often brings a smile.

Recent studies in the field of MRI have shown that the same zones that are responsible for the manifestation of pain are responsible for the perception of humor. These are the areas of the frontal lobes that react when something goes wrong. Any joke is a product of the reaction of our nervous system to paradoxes. If something does not fit into the scheme of the world perception, you laugh, unconsciously defending yourself against complexity and incomprehensibility.

I don’t think it’s proven, but people who are prone to anxiety and depression are considered to be the best humorists.Often, people known for their good sense of humor can take and unexpectedly commit suicide – for example, like the actor Robin Williams. Under the guise of humor and clownery, it is easy for a person with severe depression to hide. But in the case of, say, an introvert, it is difficult to say what is the reason for his isolation and what is the consequence. Maybe he closes himself off from society just because it is difficult for him to communicate and joke, as well as to show emotions. But this is not a vice or a disease – a person can easily live without a sense of humor.

Parrots, tobacco, testicles and other horrors • Arzamas

A terrible myth of the Nivakle people living in Paraguay and Argentina, which tells of a woman who ate her husband and was killed by her sons, as well as about strong tobacco and the heavenly village of bird-people

Indians smoking pipes. Tobacco label. Woodcut by an English school artist. Circa 18th century

© Virginia Historical Society / Bridgeman Images / Fotodom

The man and the woman went to the forest.Here is the tree, seen ahead of time. Climbing up the trunk and leaning on thick branches, the husband reached the hollow, took out an ax and began to widen the hole. Reaching out his hand, he groped in the hollow of the chick, pulled it out and threw it to his wife. There were many chicks, and he began to take them out one by one. The wife picked up the little parrots and stuffed them into her mouth. The husband looked down and saw an empty basket.
– Where are the chicks, are you eating them, or what? – the man was surprised.
– You must have gone blind, look, here they are! – the wife pointed to some object covered with a rag.
The husband took out the last parrot and asked again:
– You really don’t eat them?
– Yes, here they are, – the wife was indignant, – what do you think I’m swallowing raw meat? I just covered the chicks, otherwise the sun was shining directly on them.
– But why is your mouth in blood?
The husband began to descend.
– Wait, I will help you, otherwise you will fall, – said the wife.
– Don’t, I’ll get off fine myself.
– No, I will help: I ​​do not want you to hurt yourself.
Here he would have hit the woman with an ax – I don’t know why he didn’t. What a fool there was. The wife first put her hands up so that he leaned on his leg, then supported him under the buttocks. And then she grabbed the scrotum – the husband screamed in pain. She pulled him to the ground and continued to crush his testicles, then began to beat him until she killed him. When it became clear that the person was dead, she bit into the scrotum with her teeth, tore off the testicles and stuffed them into the bag. After that, she slowly began to eat the body. After eating it to the bone, the woman headed for the house.
– And where is the father? The children asked.
“He’s late, he’ll come soon,” her mother reassured.
“I’m going to my neighbor,” she added, seeing that a salad was being prepared in the house nearby.
– You have no salt? – asked the neighbor.
– Hey, get the salt out of my bag and bring it here! – the woman turned to her son.
The first thing the boy saw in the bag was the male testicles.
– Is it really my father, what a horror! – thought the child.Of course, he should have been silent about his find, but instead the boy ran to the neighbors, waving his testicles like a rattle. The mother reacted instantly. She grabbed the two women standing next to her and knocked them off with their heads. Then she pulled the testicles out of the boy’s hands and stuffed it into her mouth. She began to chew them along with the salad, while the two women lay unconscious on the floor.
Having finished with the salad, the ogre returned home.
Night has come. A mother and her three sons were lying side by side.The woman raised herself a little and felt the liver of each of the children.
– This one is still quite small, and this one has more, but also not very much, but the older one is pretty decent, – she reflected. – We’ll have to start with him!
Satisfied, she closed her eyes. The younger brother only pretended to be asleep. He watched his mother and heard her murmur. As soon as the woman dozed off, the boy gently awakened the brothers.
“We have to trap her! He urged.
– And still a shame – to kill your own mother! The middle responded. – Although, if we do not kill her, then, of course, she will eat us. So I’ll have to kill.
– Enough to argue, get up and hurry up! The elder whispered insistently.
The brothers crept to the place where their mother used to draw water. Bending down a tree, they pulled a rope with a noose.
– Let me try, – said the younger and stepped on the noose.
The tree straightened, dragging the boy with it, he swayed in the air.
– Excellent! – wheezed the younger brother. – Just unhook it soon!
The brothers set the trap again and returned to the house. In the morning they woke up their mother.
– Don’t you think we have little water?
“I’ll go later,” the woman waved her off.
– No, not later, we want to eat! – the children stuck.
The mother gave in and went to the river.
– No, mom, not there, the water is muddy there! – shouted the brothers, deliberately muddying the water everywhere, except for the place where the trap was.
Here the woman touched the noose and at the same second hung in the air, belching curses and regrets that she had not eaten the children the day before.
– You will die! – the children shouted in chorus, now we will finish with you!
The boys warmed up some wax. They rolled balls of wax, placing them in each thorn. They stuck these balls to arrows and began to fire at the mother’s body, beating in convulsions. They aimed in the face and stomach, immediately knocked out both eyes. The ogre tried to pull out the pierced thorns, but the thorns broke off.And then she spoke.
“I’m dying, my children. As soon as I give up, lay me down on a guaviri grass mat and set me on fire. Then you will see what comes out of me.
– Poor mother! – the youngest of the sons regretted the woman. – But what else could we do? After all, she herself was going to kill us, and in addition she ate her father!
It took a long time before the woman actually died. However, the children did not dare to come closer and continued to shoot. Finally, the elder told them to stop.
“Help me take it out,” he commanded, “and immediately drag it over there, you see where the guavirami grass grows!
It took a lot of work to burn the body to the ground. The boys stood by the blazing fire and lamented.
“What a pity,” they said, “my own mother! She would never have been killed if she hadn’t turned into something strange. Has deprived us of our father!
When the brothers returned to the village, their peers shouted after them:
– Look, these three killed their mother, and now they are going home, look at them!
For the rest of the day, the brothers cut the reeds and made new arrows.
Soon they visited the place where the mother was burned. An unusual fragrant tobacco plant grew there. They tried to smoke it and felt nauseous, but soon they got used to it and even began to like the smoke. After drying the tobacco leaves, the boys went to the village. An old man came out with a pipe in his hand.
– Can’t you find a cigarette? – he asked.
The brothers gave him leaves, the old man inhaled the smoke and immediately fell, losing consciousness.
– Oh, and this tobacco is strong! – people admired.
Every man got a share of the smoke.
The next day, grabbing armfuls of prepared arrows, the boys came out on level ground and aimed their bows upward. The first arrow came back, but the next one dug into the firmament. The arrows fired after her got stuck at the end of one another, forming a chain hanging down to the ground. The younger brother climbed first, followed by the rest. That chain was strong, those shamans were strong! Here is the sky. The brothers walked across the level field, then got out onto the road and walked past corn crops and vegetable gardens with melons, straight into the village of bird-people.
– Look, who came to us! – said the inhabitants pouring out towards them. – After all, these are the same famous boys who killed their mother!
The brothers then only once went down to earth – to see if the tobacco grows well. They never returned, remaining in heaven. These were ancient people, people of bygone times. So I got to the end.

90,000 let’s talk about treatment … / Blog of the company Dr. Shilova’s Clinic of Ophthalmology / Habr

We know that no one is immune from glaucoma.

The number of patients with glaucoma worldwide is more than 100 million (!) People. Nine out of ten blind people live in developing countries, and two-thirds of them could be cured if they were treated on time.

Glaucoma is the second cause of blindness after cataracts – up to 20% of all cases of the disease end in it. Some people do not know about the disease. Glaucoma is often detected at 2-3rd or at the last, 4th stage, when it is often impossible to help a person. In Russia, glaucoma has recently become the first cause of irreversible blindness, overtaking traumatism and vascular diseases of the eye.

Despite a serious breakthrough in understanding many problems of glaucoma over the past few years, it must be admitted that no effective methods of preventing the disease, its early (rather cheap method!) Detection and methods of treatment available everywhere have been proposed.

The trouble is that the prevention of this disease has been stopped long ago. Previously, all Soviet people after forty were required to measure eye pressure once a year. The polyclinics had medical examination rooms, people with increased intraocular pressure were referred to an ophthalmologist.And so about half of patients with glaucoma were identified. Now there is nothing of the kind. The salvation of the patients became the work of the patients themselves (that is, the drowning ones).

Since the treatment of glaucoma is the same dangerous occupation as speleology – you climb into the darkness, and what and when will fall on your head is unknown to science. And if it doesn’t fall, you’ll drown yourself or suffocate – there are options. When you guess where you got to, it will be too late. Let me start with a few of the rules outlined below.

Rule # 1

If you are diagnosed with glaucoma, then this disease will accompany you throughout your life.This means that some part of the optic nerve has been damaged. Therefore, one cannot say “I had my glaucoma removed” even after the operation. Life with glaucoma is not a death sentence, but we must not forget about it.

Rule No. 2

This imposes a number of lifelong restrictions and requires regular use of drops – about them below. If you are respectful of your illness, the rate of its progression will slow down significantly.

Rule No. 3

Regular lifelong visits to an ophthalmologist are required to monitor the level of intraocular pressure.Ideally monthly. Once every 6 months, studies should be done to assess the visual fields and tomograms of the optic nerves in both eyes. This is dynamic control.

Believe me, those patients who did not comply with prescriptions, refused surgical treatment, disappeared for months and years, lost their sight, and then lamented that their vision was irretrievably lost.

Rule No. 4

If nothing hurts, do not think that there is no disease and all the dangers are exaggerated. A feature of glaucoma is the absence of symptoms in the early and advanced stages of the disease.The patient himself does not know about the disease until he begins to lose his sight.

In order to notice the disease in time, a preventive examination by an ophthalmologist is imperative. You need to pass it once a year, and after 50 years – twice a year.

Rule No. 5

Do not look for a “miraculous” pill, “magic” drops or “healing all ailments” devices, so actively offered on the pages of newspapers, on radio and television, teeming on the Internet, tips on how to cure glaucoma with folk remedies.Thus, you will lose that precious time for treatment and it will be impossible to catch up.

Use evidence-based medicine!

What treatment for glaucoma is currently being performed?

All types of treatment for glaucoma are aimed at normalizing intraocular pressure, improving nutrition in the tissues of the eye and in the optic nerve, as well as stabilizing visual functions.

Conservative treatment of glaucoma

That is, the instillation of various types of drops in a certain mode, and for each eye it is selected separately.

These therapies are most common in the early stages of glaucoma treatment. It can also be an addition to other types of treatment – laser or surgical.
Some medicinal substances are aimed at reducing the production of intraocular fluid. Others, using special mechanisms, are aimed at improving the outflow of intraocular fluid and thereby lowering intraocular pressure. There are also combination drugs that combine both directions.

Are drops for glaucoma harmless?

Modern drops for glaucoma are effective in most cases, but not always harmless.

The drops contain the active ingredient in the form of a solution, as well as a preservative such as benzalkonium hydrochloride. It has a negative effect on the ocular surface. With prolonged use (we are talking about years), especially if the doctor does not change the drug, and the patient uses the same medicine for a long time, dry eye syndrome (redness, pain, dryness) may develop.

Possible allergic reactions and intolerance to general and local drugs.
In addition, reactions of the body as a whole are possible, for example, interruptions in heart rhythm, low blood pressure, sleep disturbances and dizziness, etc.p.

A competent doctor from a huge arsenal of drops must choose a suitable one or find a replacement. If this does not work, surgical help is needed.

Medical treatment of glaucoma is prescribed by an ophthalmologist only after a complete ophthalmological examination is purely individual – how the examination is carried out is written here.

It is very dangerous to self-medicate glaucoma – do not use or cancel antiglaucoma drugs yourself, do not violate the mode and frequency of instillation.By doing this, you can cause irreparable harm to your eyes and lose your sight.

And, here’s another, in my (and not only) opinion – taufon and emoxipin, so beloved by everyone, are useless in this diagnosis. Glaucoma and cataracts are not treated. They do not reach the lens and optic nerve. “Holy water” is even more effective.

Laser treatment of glaucoma

1. Patients love the word “laser”. So, only with

angle-closure glaucoma

is it 100% effective.In cases of closed and narrow angles, a procedure such as laser iridectomy is the guarantor of prevention of an attack of angle-closure glaucoma.

In the case of angle-closure glaucoma (we wrote about it here), the angle of the anterior chamber, in which the main outflow collector of the Schlemm canal passes, is blocked by the root of the iris. By the way, this condition can be periodic, for example, it manifests itself only when the pupil dilates (at night, during stress, etc.).

Predisposing factors – farsightedness (“short eye”) + “thick” lens (thickens with age) + anterior lens attachment + small anterior chamber

Then this is what happens:

Fluid accumulates in the posterior chamber, the iris blocks the outflow channel, the pressure rises, the person experiences eye pain, the eye turns red and vision loss may occur if the outflow is not unblocked.

In this case, a hole is made in the iris using a laser perforator – peripheral laser iridectomy (iridotomy). It is also proposed to perform it in the case when the angle of the anterior chamber has not yet closed, but there is such a risk. Narrow angles are determined by inspection with a special goniscopic lens.

This is how laser iridectomy and the eye after it looks schematically under a microscope

And here is the video of the procedure:

If the laser cannot make the hole, surgical iridectomy is performed in the operating room.

Laser iridectomy is performed using laser devices with different wavelengths: using a monopulse solid-state neodymium YAG laser or argon gas.

2. Now about laser treatment for open-angle glaucoma. And, let me remind you, 80% of all cases it is she – open-angle glaucoma . Everything is not so simple here. Types of laser surgery in the treatment of open-angle glaucoma are laser trabeculoplasty or trabeculopuncture.The method involves the application of point burn applications on a specific area of ​​the trabecula (the network through which the outflow occurs).

It is assumed that the pigment that clogs it is “knocked out” of the trabecula, the fibers wrinkle and increase the gaps for outflow – they achieve the “popcorn effect”. For this, argon and neodymium

laser trabeculoplasty (LTP)

(514/532 nm) and diode infrared or micropulse LTP (810 nm) are used.

In fact, such a procedure itself is capable of further increasing intraocular pressure, if the effect is, it will be very short-term and unstable.As an independent procedure, it is dangerous, because after it the patients consider themselves “cured” by the laser and often stop instilling drops and stop visiting the ophthalmologist. And glaucoma is progressing imperceptibly!

A laser procedure such as Descemethogoniopuncture (DPH) with these lasers is often used in addition to microsurgical non-penetrating deep sclerectomy (NHD), which will be discussed below. Then the shots are applied along the Descemet membrane, and not along the channel – it turns into a “sieve” and further enhances the outflow.

3. And finally, the laser for cyclophotocoagulation . In this case, it doesn’t matter what was the reason.

Used in advanced end-stage disease. When the eye does not see or almost does not see, it begins to hurt and disturb. On the surface of the eyeball or inside it (using an endoscope combined with a laser), coagulates are applied at a distance of 1.5 – 3 mm from the limbus in the area of ​​the projection of the processes of the ciliary body, a rather painful procedure.