What Is a Corneal Ulcer (Keratitis)?

A corneal ulcer (also known as keratitis) is an open sore on the cornea. The cornea covers the iris and the round pupil, much like a watch crystal covers the face of a watch. A corneal ulcer usually results from an eye infection, but severe dry eye or other eye disorders can cause it.

Corneal Ulcer Symptoms

Symptoms of corneal ulcers include:

• redness of the eye
• severe pain and soreness of the eye
• the feeling of having something in your eye
• tearing
• pus or other discharge
• blurred vision
• sensitivity to light
• swelling of the eyelids
• a white spot on your cornea that you may or may not be able to see when looking in the mirror

See your ophthalmologist immediately if you think you have a corneal ulcer or have any eye symptoms that concern you. Corneal ulcers can badly and permanently damage your vision and even cause blindness if they are not treated.

Who Is at Risk for Corneal Ulcer?

People at risk for corneal ulcers include:

• contact lens wearers
• people who have or have had cold sores, chicken pox or shingles
• people who use steroid eye drops
• people with dry eye
• people with eyelid disorders that prevent proper functioning of the eyelid
• people who injure or burn their cornea

If you wear contact lenses, safe handling, storage and cleaning of your lenses are key steps to reduce your risk of a corneal ulcer. It is important to learn how to take care of your contact lenses.

Corneal Ulcer Causes

You can prevent many causes of corneal ulcers. Use the correct protective eyewear when doing any work or play that can lead to eye injury. And if you wear contact lenses, it is important to care for your contact lenses correctly.

Corneal ulcers are usually caused by the following types of infections:

Bacterial infections.  These are common in contact lens wearers, especially in people using extended-wear lenses.

Viral infections. The virus that causes cold sores (the herpes simplex virus) may cause recurring attacks. These attacks are triggered by stress, an impaired immune system, or exposure to sunlight. Also, the virus that causes chicken pox and shingles (the varicella virus) can cause corneal ulcers.

Fungal infections. Improper use of contact lenses or steroid eye drops can lead to fungal infections, which in turn can cause corneal ulcers. Also, a corneal injury that results in plant material getting into the eye can lead to fungal keratitis.

Parasitic (Acanthamoeba) infections. Acanthamoeba are microscopic, single-celled amoeba that can cause human infection. They are the most common amoebae in fresh water and soil. When Acanthamoeba enters the eye it can cause a bad infection, particularly for contact lens users.

Other causes of corneal ulcers include:

Abrasions or burns to the cornea caused by injury to the eye. Scratches, scrapes and cuts can become infected by bacteria and lead to corneal ulcers. These injuries can happen from fingernail scratches, paper cuts, makeup brushes and tree branches. Burns caused by corrosive chemicals found in the workplace and at home can cause corneal ulcers.

Dry eye syndrome.

Bell’s palsy and other eyelid disorders that prevent proper eyelid function. If the eyelid does not function properly, the cornea can dry out, and an ulcer can develop.

Corneal Ulcer Diagnosis

Your ophthalmologist will use a special dye called fluorescein (pronounced FLOR-uh-seen) to light up any damage to your cornea. They will then examine your cornea using a special microscope called a slit lamp. The slit-lamp exam will allow your ophthalmologist to see the damage to your cornea and determine if you have a corneal ulcer.

If your ophthalmologist thinks that an infection has caused your corneal ulcer, they may take a tiny tissue sample. Examination of this sample helps identify and properly treat the infection.

Corneal Ulcer Treatment

Antibiotic, antifungal or antiviral eye drops are the treatments of choice. Sometimes your ophthalmologist will prescribe antifungal or antiviral tablets. In other cases, they will treat you with an injection of medication near the eye.

Your ophthalmologist may prescribe steroid or anti-inflammatory eye drops after your infection has improved or is gone. This should reduce swelling and help prevent scarring. Steroid eye drop use is controversial for corneal ulcer. You should only use them under close supervision by your ophthalmologist. It is possible that steroid eye drops may worsen an infection.

Your ophthalmologist may prescribe pain medication to take by mouth to reduce pain.

If your symptoms suddenly change or get worse during treatment, then let your ophthalmologist know right away.

Symptoms to look for include:

• pain and redness of the eye
• tearing and discharge from the eye
• blurry vision

Surgery. A corneal transplant can replace your damaged cornea with a healthy donor cornea to restore vision. When the infection is gone and the ulcer is healed after treatment with medication, sometimes a significant scar remains. In this case, a transplant may be done to improve vision. And if corneal ulcers cannot be treated with medication, you may also need corneal transplant surgery to keep your vision.

Corneal Ulcer – Eye Disorders

By

Melvin I. Roat

, MD, FACS, Sidney Kimmel Medical College at Thomas Jefferson University

Reviewed/Revised Aug 2022 | Modified Sep 2022

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Topic Resources

A corneal ulcer is an open sore on the cornea (the clear layer in front of the iris and pupil) that is usually caused by an eye infection.

• Contact lenses, injuries, disorders, drugs, and nutritional deficiencies can also cause open sores (ulcers) to form on the cornea.

• Ache, foreign body sensation (the ache and foreign body sensation can be severe), redness, tearing, and light sensitivity are common symptoms.

• Doctors diagnose an ulcer based on the appearance of the person’s cornea.

• Antibiotic, antiviral, or antifungal eye drops are usually given as soon as possible.

(See also Herpes Simplex Keratitis Herpes Simplex Keratitis Herpes simplex keratitis is an eye infection that involves the cornea (the clear layer in front of the iris and pupil) and is caused by herpes simplex virus. The infection commonly recurs and… read more .)

Corneal ulcers may be caused by infections with bacteria, fungi, viruses, or parasites such as Acanthamoeba (which lives in contaminated water). Ulcers may begin with a corneal injury, such as with severe dry eyes, if a foreign object scratches, penetrates, or lodges in the eye or, more often, if the eye is irritated by a contact lens, especially when contact lenses are worn during sleep or are not adequately disinfected (see Care and complications Care and complications of contact lenses Refractive errors can be corrected with glass or plastic lenses mounted in a frame (eyeglasses) or with a small lens made of plastic floating or resting on the cornea (contact lens). Good vision… read more ). Viral corneal ulcers (often due to herpesvirus Herpes Simplex Keratitis Herpes simplex keratitis is an eye infection that involves the cornea (the clear layer in front of the iris and pupil) and is caused by herpes simplex virus. The infection commonly recurs and… read more ) can be triggered to recur by physical stress or may recur spontaneously. A deficiency of vitamin A and protein may lead to the formation of a corneal ulcer. However, such ulcers are rare in the United States.

When the eyelids do not close properly, the cornea may become dry and irritated. This kind of irritation can lead to injury and the development of a corneal ulcer. Corneal ulcers may also result from in-growing eyelashes (trichiasis Trichiasis Trichiasis is misalignment of eyelashes, which rub against the eyeball, in a person who does not have entropion. Trichiasis develops most commonly some time after chronic blepharitis (inflammation… read more ), an in-turned eyelid (entropion Entropion and Ectropion Entropion is a condition in which the eyelid is turned inward (inverted), causing the eyelashes to rub against the eyeball. Ectropion is a condition in which the eyelid is turned outward (everted)… read more ), or eyelid inflammation (blepharitis Blepharitis Blepharitis is inflammation of the edges of the eyelids, possibly with thickening scales, crusts, shallow ulcers, or redness and swelling at the edges of the eyelids. The inflammation is caused… read more ).

Corneal ulcers cause redness, pain, usually a feeling like a foreign object is in the eye (foreign body sensation), aching, sensitivity to bright light, and increased tear production. The ulcer often appears as a white or dull and grayish spot on the cornea. Sometimes, ulcers develop over the entire cornea and may penetrate deeply. Pus may accumulate behind the cornea, sometimes forming a white layer at the bottom of the cornea (called a hypopyon). The conjunctiva usually is bloodshot. The deeper the ulcer, the more severe the symptoms and complications.

VIDEO

Corneal ulcers may heal with treatment, but they may leave a cloudy scar that impairs vision.

Other complications may include deep-seated infection, perforation of the cornea, displacement of the iris, and destruction of most or all of the tissue in the eye socket.

• An eye examination

• Sometimes cultures

Doctors evaluate the ulcer by using a slit lamp What Is a Slit Lamp? (an instrument that enables doctors to examine the eye under high magnification). To see an ulcer clearly, a doctor may apply eye drops that contain a yellow-green dye called fluorescein. The fluorescein temporarily stains damaged areas of the cornea, making it possible for the doctor to see damaged areas of the cornea that are not otherwise visible.

In some situations, doctors scrape the surface of large ulcers for a sample. The sample is then grown in a laboratory (cultured) to identify the bacterium, fungus, virus, or protozoa causing the infection. Once the organism is identified, doctors choose the best drug to fight the infection.

• Antibiotic, antiviral, or antifungal eye drops

• Drops that dilate the eye

• Sometimes transplantation of the cornea

A corneal ulcer is an emergency that should be treated immediately.

Antibiotic, antiviral, or antifungal eye drops are usually needed immediately and must be given frequently, sometimes every hour around the clock for several days.

Drops that dilate the eye, such as atropine or scopolamine, can help with pain and reduce the chance of complications.

Corneal transplantation Corneal Transplantation Corneal transplantation (keratoplasty) is a common and highly successful type of transplantation. A scarred, severely painful, perforated, misshapen, or cloudy cornea (the clear layer in front… read more (keratoplasty) is sometimes needed.

Generic Name	Select Brand Names
fluorescein	AK-Fluor, Fluorescite, Fluorets , Fluor-I-Strip, Fluor-I-Strip A. T., Ful-Glo, Ophthalmicflur
vitamin a	A Mulsin, Aquasol A, Dofsol-A
atropine	Atreza, Atropine Care , Atropisol , Isopto Atropine, Ocu-Tropine, Sal-Tropine
scopolamine	Isopto Hyoscine, Maldemar, Scopace, Transderm Scop

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Corneal ulcer in a cat is one of the most dangerous eye diseases

In cats, the most common and severe corneal diseases are corneal ulcers. A corneal ulcer is an inflammation of the cornea, accompanied by necrosis of the epithelium and stroma with the formation of a defect.

This disease has a different nature of the course and clinical manifestations. Most often, this disease occurs in cats of Persian and exotic breeds.

Clinically, a corneal ulcer is manifested by a closed eye (blepharospasm), increased lacrimation or purulent discharge, photophobia, and pain.

On the surface of the cornea, you can notice a roughness, depression or bubble, which may indicate a perforated ulcer closed by exudate.

The causes of corneal ulcers are eye trauma, torsion of the eyelids, advanced conjunctivitis, keratitis and other infections of the eye.

A corneal ulcer is one of the most dangerous diseases that must be treated medically or surgically, because. delay in providing assistance may threaten blindness or loss of the eye as an organ. The most effective operation that allows you to save the eye and save vision is keratoplasty (corneal transplant).

In our center, ophthalmologists adhere to the high standards of diagnosis and treatment of your pets and find an individual approach to each case. We provide a full range of diagnostic and treatment services.

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Cataract is a disease characterized by clouding of the lens and decreased vision, up to its complete loss. Cataracts are widespread not only in humans, but in all animals.

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Medical, laser and surgical treatment of glaucoma

Glaucoma is a chronic eye disease characterized by a constant or periodic increase in intraocular pressure, the development of trophic disorders in the outflow tracts of intraocular fluid, the retina and optic nerve.

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Trauma and damage to the eye

Injury to the organ of vision is one of the most severe pathologies of the organ of vision in animals. Even minor damage can lead to irreversible consequences and permanently deprive your pet of the ability to see.

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Conjunctivitis, keratitis

Most often (more than 50%), owners of dogs and cats with infectious and inflammatory eye diseases in their pets turn to our center.

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Inversion and eversion of the eyelids

This disease is expressed in the pathological condition of the eyelid, when its edge is wrapped inward towards the eyeball.

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Epiphora is a pathology of the lacrimal apparatus of the eye, which is manifested by excessive lacrimation, the formation of crying eye syndrome.

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Shilkin A.G.

Eye inflammation in a cat, cataract in a dog? Treatment with us – the best doctors of our Center will help you!

Dr. Shilkin’s Veterinary Center examines and treats any eye disease in pets. If you are concerned about the deterioration of your pet’s vision or other eye problems, the specialists of our center are always ready to help you by consulting on any questions and vision problems. The eyes of a cat or dog are inflamed and watery, your pet has injured his eye, do you think that the animal’s eyesight has deteriorated? Here you will find not only prompt veterinary care, but also a sensitive attentive attitude to each patient.

If you notice that your pet’s eyesight has deteriorated, the eyes of a dog or cat are inflamed or festering, you should not postpone a visit to a specialist. Timely access to an ophthalmologist will help to avoid serious vision problems. Experienced veterinarians of our center will conduct an examination and determine whether surgery is necessary

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Shilkin Alexey Germanovich

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Aleksey Germanovich Shilkin – Leading Veterinary Ophthalmologist, Head of the Center for Veterinary Ophthalmology Dr. Shilkin A.G., Candidate of Medical Sciences, Associate Professor. Winner of the “Golden Scalpel” award in the nomination for professionalism as the best doctor of the year and the “Balto” award for scientific work. Awarded with a medal. V. N. Mitina “For contribution to clinical veterinary medicine.”

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Rotanov Denis Alexandrovich

Veterinary ophthalmologist, microsurgeon, candidate of veterinary sciences

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Pavlova Tatyana Nikolaevna

Candidate of Veterinary Sciences, veterinarian ophthalmologist, microsurgeon

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Artyushina Yulia Yurievna

Candidate of Veterinary Sciences. Veterinary ophthalmologist, ophthalmic surgeon

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Voiteha Maria Alexandrovna

Candidate of Biological Sciences, ophthalmologist, microsurgeon

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Golubeva Oksana Vladimirovna

Veterinary ophthalmologist, microsurgeon

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Zubkova Elena Vladimirovna

Veterinary doctor – ophthalmologist, microsurgeon

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Novikova Ksenia Alexandrovna

Veterinary ophthalmologist, ERG specialist

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Kulyagina Yulia Igorevna

Candidate of Veterinary Sciences, ophthalmologist, microsurgeon

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Mochalova Ulyana Eduardovna

Veterinary ophthalmologist, microsurgeon

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Veterinary ophthalmologist, microsurgeon

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Orlova Maria Nikolaevna

Veterinary ophthalmologist, microsurgeon

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Our specialists have extensive experience in the diagnosis and treatment of ophthalmic diseases in animals. Continuous professional development, participation in international conferences allow us to put into practice the most modern achievements of veterinary ophthalmology.

Dear owners of our tailed patients! We will be grateful if you leave a review about the work of the specialists of the Center for Veterinary Ophthalmology Dr. Shilkin A.G. and help us get even better.

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A gynecologist’s suspicion requires confirmation by an ophthalmologist. And we dragged ourselves to the doctors. Not that they gave themselves to the first person they met, they visited status places, but there was still no readiness to put the pet on the operating table. Turned to your favorite word of mouth. And it sent us to Dr. Shilkin’s Clinic. To say that I am delighted, and especially in such a situation, is to say nothing. Only a couple of very cool “human” ophthalmological clinics have such equipment in an operating room like there. The level of education of doctors and equipment of offices is simply off scale. Care … Well, at least the fact that the examination conducted by the doctor with all sorts of “-scopes” is observed by both the assistant and the owner of the animal, moreover, on different monitors located at the right angle, is worth a lot. Everything seen is commented on. Moreover, even the “banal” microscope, with which the smear is viewed, has additional monitors. Communication… I think if all “human” doctors talked like that, we wouldn’t have lawsuits. First, it needs to be heard. Such empathy is rare. And secondly, for example … “After the operation, … complications are possible. To reduce their risk, we will prescribe … But these drugs have side effects …. Most often they appear on …. a day. But if you notice…before, call – write – come.” Everything is spoken clearly, first by a doctor, then by an assistant, and written down in the recommendations. By the way, I was quickly “calculated”. In the second minute of examining the dog in monologue mode, the doctor asked what kind of doctor I was. Apparently it’s written on the forehead. Common friends, of course, found. Empathy, about which I wrote above, is not connected with the fact that I am “my own”. It so happened that I was forced to watch different animals, their owners, doctors and other employees of the clinic for a very long time and carefully, so I can state this with all responsibility. P.S. After 8 months, the doctor “liked” the operated eye even more than the second, completely healthy one. Not advertising. The dog was operated on by Rotanov D.A.

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To imagine our pet with glassy or sewn eyes is beyond all strength. And this could happen. At first, the eye began to water.

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Then the dog squinted at him. We turned to the best clinic in the city of Korolev. They prescribed drops. The eye began to turn blue. Then the second. The dog began to stumble and literally fell off his feet. Friends recommended Shcherbinka. We arrived at Konstantinovsky. He said that everything is very bad. The dog is blind. He had to leave for a symposium, and he advised us A.G. Shilkin. How attentively and thoughtfully he received us! I called my friends, organized an emergency examination, and the next day – an operation. Denis Alexandrovich Rotanov … They say about such people – a doctor from God. Golden hands, huge heart! There are several components of success: high professionalism and many years of practice, unique modern equipment, deep human participation and sympathy. There are still good medicines that need to be used correctly. The eyes were saved! This is a man-made miracle! Can words express gratitude? Saying thank you is so little! May goodness return to you, to your family and friends! Ready to answer all questions and provide details. Call: 8-903-000-50-53. Irina Yurievna Mishina, editor-in-chief of a number of publications

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From the bottom of my heart, I EXPRESS DEEP, SINCERE GRATITUDE TO THE CURRENT OPHTHALMOLOGIST, Pavlova Tatyana Nikolaevna!

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Dates of treatment: March 18, 2020, (initial appointment), and April 15, 2020 (Control appointment), diagnosis: Allergic conjunctivitis. A comprehensive eye examination was performed (in my dog), treatment was prescribed. Thank you from the bottom of my heart, Tatyana Nikolaevna, for the Highest professionalism, Responsiveness, Warmth, Attention, and Sensitive attitude, to my beloved (dog-dachshund Martha), and also express my gratitude to the Center for Veterinary Ophthalmology (Dr. Shilkin A.G.), for an attentive approach (to animals) and clear professional work. WISH YOU SUCCESS AND PROSPERITY.

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Many thanks to Maria Alexandrovna Voiteha. My cat, which I adopted from a shelter, had an eye problem. The usual veterinary clinic did not help.

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Maria Alexandrovna prescribed complex treatment and after 2 months the cat recovered. We are currently on maintenance treatment. It turned out that he had herpes on his eyes. Great caring and experienced doctor!

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We bought a baby beagle, immediately went to the clinic for a checkup. Everything passed, but they couldn’t help us with the eyes (and they also scared us that the animal was blind!).

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Any ophthalmic operation, from the simplest to the most complex, requires a highly skilled approach to general anesthesia.

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Acute attack of glaucoma in dogs and cats is a pathology characterized by a sharp increase in intraocular pressure (IOP), fulminant course and irreversible loss of vision. Taking into account the anatomical and physiological differences between the human and animal eyes, a sharp increase in IOP will be more accurately classified not as an acute attack of glaucoma (APG), but as acute ophthalmohypertension (OHH).

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What should be considered when choosing a clinic? Of course, the professionalism of doctors!

Video clips demonstrate the performance of complex microsurgical operations by specialists of the Center for Veterinary Ophthalmology Dr. Shilkin A. G.

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On January 23, EVCO certification for hereditary eye diseases and patella status will be held in our center.

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Erosions and ulcers of the cornea in cats and dogs

Author: Vasilyeva Ekaterina Valerievna, veterinary ophthalmologist. Veterinary Clinic of Neurology, Traumatology and Intensive Care, St. Petersburg.

Corneal erosion and ulceration are very common pathologies in the eyes of animals. The clinical signs of these pathologies are similar; in animals, lacrimation, blepharospasm, conjunctival hyperemia, and corneal edema are observed. However, treatment tactics and prognosis regarding the condition of the eye and vision can vary greatly depending on the diagnosis and associated conditions.

Anatomy

The cornea is a transparent part of the outer fibrous membrane of the eyeball, it is one of the light-transmitting and refracting media of the eyeball. Normally, the cornea is intact, transparent, without vessels, pigment, inclusions. The thickness of the cornea in dogs in the central part is 0.6-1.0 mm (depending on the size of the animal), in cats it is 0.8-1.0 mm.

The cornea of ​​cats and dogs consists of 4 layers: epithelium, stroma, Descemet’s membrane, endothelium. From the surface, the corneal epithelium is covered with a tear film, which performs a protective function and maintains the moisture of the cornea (Fig. 1. Structure of the cornea. “Veterinary Ophthalmology”, edited by Kirk N. Gelatt, 5ed, 2013).

Fig 1. Structure of the cornea

Corneal stratified squamous non-keratinized epithelium consists of a layer of basal cells lying on a basement membrane, 2-3 layers of pterygoid cells and 2-3 layers of squamous cells 5ed, 2013).

Fig 2. Corneal epithelium

The corneal stroma makes up 90% of the thickness of the cornea and consists of parallel plate-forming collagen fibers and keratocytes.

Descemet’s membrane is an elastic, cell-free collagen membrane that separates the stroma and endothelium.

Corneal endothelium is a single layer structure of hexagonal cells lining the inner surface of the cornea, the function of this layer is to maintain the corneal stroma in a moderately dehydrated state, which ensures its transparency (Fig. 3. Descemet’s membrane and corneal endothelium. “Veterinary Ophthalmology”, edited by Kirk N. Gelatt, 5ed, 2013).

Fig.3. Descemet’s membrane and corneal endothelium

Pathologies

Corneal erosion is a lesion of the cornea, accompanied by loss of epithelium without involvement of the stroma.

The causes of erosion can be mechanical (trauma), chemical (shampoo), thermal, infectious (herpesvirus in cats), physical (drying of the cornea with dry keratoconjunctivitis, lagophthalmos).

For diagnosis, examination with a slit lamp is used: a surface defect of various shapes and sizes is visualized, and a fluorescein test – a fluorescein solution is dripped into the conjunctival sac: a place on the cornea, devoid of epithelium, absorbs the dye and has a bright green color (Fig. 4. Corneal erosions in a cat with herpes virus stained with fluorescein “Color atlas of canine and feline ophthalmology”, Dziezyc, Millichamp, 2004). Previously, according to indications, a Schirmer test is performed to determine the amount of lacrimal fluid and material is taken from the conjunctival sac for research on infections (cats).

Fig.4. Corneal erosions in a cat with herpesvirus stained with fluorescein

After corneal erosion is detected, a thorough examination of the edges of the eyelids and the conjunctival sac is carried out to exclude possible causes of erosion: ectopic eyelashes, aggressively growing hard distichial eyelashes, neoplasms of the eyelids, foreign bodies in the conjunctival sac.

When the cause is detected and eliminated, the erosion is closed by the epithelium after a few days (48-72 hours). In addition to specific treatment aimed at eliminating the cause, antimicrobial drops and moisturizers (gels) are used in the conjunctival sac for 5-7 days.

We should also consider chronic non-healing corneal erosion in dogs (boxer ulcer, indolent erosion, spontaneous chronic epithelial defect). Boxer dogs, dachshunds, bulldogs and many other breeds are susceptible, most often dogs older than 5-6 years. This type of corneal erosion is characterized by the fact that the defect does not heal for weeks or even months despite the absence of visible causes and the use of drugs. The reason for this condition is a violation of the contact of epithelial cells with the underlying basement membrane, which leads to the fact that the normally regenerating epithelium is not fixed on the membrane and sloughs off, as a result, erosion cannot close. Chronic erosion has a characteristic appearance when viewed with a slit lamp: the edge of the defect is usually uneven and elevated above the stroma (Fig. 5. Chronic erosion of the cornea without staining with fluorescein), staining with fluorescein shows leakage of the dye under the loose edges of the epithelium, the area of ​​staining is larger than the area of ​​the cornea devoid of epithelium (Fig. 6. Chronic corneal erosion after staining with fluorescein. Veterinary Ophthalmology, edited by Kirk N. Gelatt, 5ed, 2013).

Fig.5. Chronic corneal erosion without fluorescein staining

Fig. 6. Chronic corneal erosion after staining with fluorescein

Therapeutic treatments for chronic erosion are not effective, as they do not solve the problem of epithelial cell attachment. There are several treatments for chronic erosion:

1. Removal of loose epithelium with a cotton swab (the defect that is exposed after this is usually larger in area than the original one) followed by the application of antimicrobial drops and gels. This procedure is carried out using local anesthesia – eye drops, takes 3-5 minutes. The effectiveness of this procedure is low, repeated treatments are required at least 2-3 times, healing is slow, often with the formation of a rough scar.
2. Pinpoint/lattice keratotomy is a method in which point or line notches are applied to the surface of the cornea with an insulin needle, forming depressions in the superficial stroma. This procedure can be performed using local anesthesia only in very calm animals, most animals require sedation, this procedure is often combined with covering the eye with a third eyelid apron, which promotes better healing. The efficiency of keratotomy is 60-80%.
3. Treatment of the pathological area with a diamond bur. Diamond burr is a special device for scarifying the cornea, which allows you to remove loose epithelium and create a surface for good engraftment of a new epithelium. The advantage of this technique is the ability to carry out the procedure without the use of general anesthesia, only with the use of a local anesthetic. Sometimes it is required to repeat the procedure after 7-14 days, possibly the formation of a rough scar during the healing of the defect.
4. An effective method for solving the problem is superficial keratectomy – a surgical operation in which the surface layer of the cornea is removed, including a section of the basement membrane and the superficial part of the stroma, and the formed defect heals due to the complete regeneration of the surface layer, and not only due to the epithelium (Fig. 7. Superficial keratectomy: exfoliation of the cornea).

Fig.7. Superficial keratectomy: corneal dissection

The procedure is performed using general anesthesia, after keratectomy, the eyes are protected with a temporary apron of the third eyelid or the edges of the upper and lower eyelids are partially sewn together. In the postoperative period, antimicrobial drops are used in the conjunctival sac, it is recommended to wear a protective collar. After 14 days, temporary sutures are removed from the eyelids, by this time the defect is completely epithelialized. The effectiveness of this procedure is 100%, the defect heals with moderate formation of corneal fibrosis, which is practically not noticeable after 3-6 months (Fig. 8. View of the cornea 1 month after superficial keratectomy).

Fig. 8. View of the cornea 1 month after superficial keratectomy

It is important to understand that since this type of erosion is caused by an abnormal contact between the cells and the basement membrane, there is a risk of chronic erosion in areas adjacent to the surgically treated, or in the second eye.

Corneal ulcer is a defect in the cornea involving the stroma. The depth of the ulcer can be different: ulcers with a loss of less than ½ of the thickness of the stroma can be considered shallow, with a loss of more than ½ of the thickness – deep, an ulcer with a loss of the entire thickness of the stroma, reaching the Descemet’s membrane – a descemetocele, with a loss of the entire thickness of the cornea – a through corneal ulcer (perforation ).

The causes of corneal ulcers are similar to the causes of erosions, however, in the case of an ulcer, the condition is complicated by aggressive secondary microflora, lack of adequate regeneration (for example, when using steroid hormones), pathology of the auxiliary apparatus of the eyeball (lagophthalmos, torsion of the eyelids, pathological eyelashes, dry keratoconjunctivitis ).

Diagnostic methods for corneal ulcer include examination with a slit lamp, which allows you to determine the depth of the defect, assess the condition of the anterior chamber of the eye (fluid transparency, depth of the anterior chamber), fluorescein test, a thorough examination of the edges of the eyelids and the conjunctival sac. Additional use of ultrasound of the eyeball is recommended for infected ulcers and / or severe corneal edema to detect anterior synechia, lens pathology and assess the condition of the posterior segment (vitreous and retina), it is advisable to perform ultrasound after sedation of the animal to eliminate the risk of injuring the eye when the animal resists.

Shallow corneal ulcers that occur without corneal melting (keratomalacia), in the absence of pathological eyelashes or foreign bodies in the conjunctival sac and without complicating factors: dry keratoconjunctivitis, lagophthalmos, may require only therapeutic treatment: antimicrobial drops and moisturizing gels in the conjunctival sac 3- 4 times a day, protective collar (Fig. 9. Superficial corneal ulcer, corneal edema).

Fig.9. Superficial corneal ulcer, corneal edema

If positive dynamics is noted at the control appointment, therapeutic treatment is continued until the ulcer heals with the formation of corneal fibrosis, which becomes hardly noticeable after 3-6 months. If there is no improvement at the control appointment, it is recommended to resort to a surgical method of treatment: surgical treatment of the corneal ulcer (cleaning the bottom of the ulcer from necrotic tissues and updating its edges) followed by covering the eye with a temporary apron of the third eyelid or temporary suturing the edges of the upper and lower eyelids. Surgical treatment is carried out using general anesthesia, before the treatment itself, a thorough revision of the conjunctival sac is carried out under an operating microscope. After the operation, the animal should receive an antimicrobial drug systemically, wear a protective collar, drops with an antibiotic are also used in the conjunctival sac, since even after closing the eye with temporary sutures, there remains space for the instillation of drops. The sutures from the eyelids are removed on the 10-14th day, by this time the defect has healed with the formation of moderate corneal fibrosis.

Deep corneal ulcers, as well as ulcers complicated by aggressive microflora, occurring with keratomalacia (melting of the cornea), hypopyon (accumulation of pus in the anterior chamber), miosis (narrowing of the pupil), require surgical treatment (Fig. 10. Complicated corneal ulcer: hypopyon, Fig. 11. Deep complicated ulcer: keratomalacia, hypopion).

Fig.10. Complicated corneal ulcer: hypopyon

Fig. 11. Deep complicated ulcer: keratomalacia, hypopyon

The operation is performed using general anesthesia, before the procedure, a thorough revision of the conjunctival sac is carried out. The essence of the operation is to clean the bottom and edges of the ulcer from dead tissues and cover the formed defect with a “patch”, which may consist of the conjunctiva of the animal itself, the donor cornea or special synthetic materials. The use of a “patch” allows you to replace the lost thickness of the cornea and reduce the risk of its perforation, as well as accelerate the healing of the defect. One of the methods is the use of an animal conjunctiva flap (the tissue is taken from the eyeball or from the 3rd century), the conjunctiva is fixed to the cornea with sutures and subsequently grows to the bottom of the defect (Fig. 12. Conjunctival flap fixed to the cornea, intraoperative photo).

Fig.12. Conjunctival flap fixed to the cornea, intraoperative photo

After suturing the cornea, the eye is covered with an apron of the 3rd eyelid or the edges of the eyelids are temporarily sutured. Postoperative care includes a systemic and local antimicrobial drug, mydriatics and / or drugs with antiprotease activity, it is mandatory to wear a protective collar. On the 14th day, the sutures from the eyelids are removed, the area of ​​the cornea covered by the conjunctival flap remains opaque, covered with vessels, 4-6 months after the operation, the conjunctival flap acquires a paler color, becomes smoother, its partial transparency is possible (Fig. 13. Conjunctival flap through 14 days after surgery, Fig. 14. Conjunctival flap 3 months after surgery).

Fig. 13. Conjunctival flap 14 days after surgery

Fig 14. Conjunctival flap 3 months after surgery

Descemetocele is a very deep ulcer in which there is a complete loss of the thickness of the corneal stroma, and the integrity of the eyeball is supported only by the Descemet’s membrane and endothelium.

When examined with a slit lamp, the ophthalmologist notes the characteristic features: the Descemet’s membrane protrudes slightly forward from the bottom of the ulcer (stretched by intraocular pressure), and this area looks darker (due to the transparency of the Descemet’s membrane relative to the peripheral cornea, which has a normal or even greater thickness due to edema – Fig. 15. Descemetocele).

Fig.15. Descemetocele

Also a feature of descemetocele is that the descemetocele is hydrophobic and does not absorb fluorescein solution, and the peripheral stroma of the cornea is hydrophilic and turns green, thus, the defect stains annularly (Fig. 16. Descemetocele after staining with fluorescein. “Veterinary Ophthalmology”, edited by Kirk N. Gelatt, 5ed).

Fig.16. Descemetocele stained with fluorescein

Descemetocele is an emergency condition of the eye, as there is a high risk of perforation of the eyeball in case of IOP drop, fixation of the animal, self-injury. The treatment of descemetocele is surgical, it consists in cleaning the defect from dead tissues (care must be taken to avoid intraoperative perforation) and replenishing the thickness of the cornea with an isolated conjunctival flap, the animal’s own cornea, donor cornea, synthetic materials. The material is fixed to the edges of the defect with sutures, the eye is closed with an apron of the third eyelid. Postoperative care is similar to that for deep ulcers.

Perforation of the cornea (perforation) – a state of complete destruction of the cornea throughout its entire thickness, accompanied by depressurization of the anterior chamber, a sharp decrease in intraocular pressure, outflow of intraocular fluid, can be complicated by the prolapse of the iris into the formed hole (iris prolapse), the penetration of microflora into the eyeball with subsequent development of panophthalmitis.

A penetrating ulcer occurs from a non-perforating ulcer that does not respond to therapy, moreover, the time from the onset of the first symptoms to perforation can be from 2-3 days, and the owner may also notice a sudden profuse flow of “tears” from the eye, accompanied by severe pain. Clinical signs of perforation: pronounced blepharospasm (the animal does not open its eyes), hypotonicity of the eyeball, shallow anterior chamber, miosis, observed outflow of fluid from the anterior chamber of the eye (Seidel test can be confirmed: concentrated fluorescein is applied to the ulcer and the outflow of intraocular fluid of a transparent green color is observed ). An animal with corneal perforation may not have an active outflow of intraocular fluid, this is possible with prolapse of the iris (mechanically closes the hole), already formed anterior synechia (adhesion of the iris and cornea) or blockage of the corneal hole with a fibrin clot (Fig. 17. Through ulcer of the cornea , prolapse of the iris, Fig. 18. Deep corneal ulcer with a perforation site closed by a fibrin clot).

Fig.17. Perforating corneal ulcer, iris prolapse

Fig.18. Deep corneal ulcer with perforated area covered with fibrin clot

Fresh perforation is an acute condition requiring urgent surgical sealing. In case of prolapse of the iris, it is reduced, in the case of the formation of a strong synechia and the impossibility of reduction, the necrotic tissue of the iris is cut off. Before fixing the replacement material to the cornea, the anterior chamber is washed, and its volume is returned. Postoperative treatment includes a local and systemic antibiotic, a local and systemic anti-inflammatory drug, a local mydriatic, drugs with antiprotease activity, wearing a protective collar is mandatory, rigid fixation, neck compression, pressure in the eye area are contraindicated.

Complications associated with the loss of the integrity of the eyeball include the formation of anterior synechia – adhesions of the iris with the cornea at the site of perforation, with small synechia, visual function does not decrease. A serious complication of perforation is the multiplication of aggressive microflora in the intraocular tissues, leading to inflammation of all eye tissues – panophthalmitis, this condition leads to loss of visual function and can threaten the life of the animal. Causes of panophthalmitis: lack of timely surgical treatment of a through ulcer and subsequent antimicrobial therapy or microflora resistance to the antimicrobial drug used. For diagnosis, the doctor uses a slit lamp examination, a test for reaction to blinding light (“dazzle” reflex), and an ultrasound of the eyeball. In the absence of a reaction to blinding light, and ultrasound detection of hyperechoic contents in the vitreous body and anterior chamber of the eye, retinal detachment, enucleation of the eyeball is recommended.

Totals:

In the case of corneal erosion, it is necessary to identify the cause as quickly as possible and eliminate it, in this case, the erosion heals within a few days, without traces and without affecting visual function.

In case of chronic erosion, surgical techniques are effective, they allow the cornea to heal quickly, and the clouding that occurs after healing is minimal and becomes even less pronounced over time, visual function does not deteriorate.

In the case of a corneal ulcer, an ophthalmologist evaluates its depth, the presence of concomitant complicating conditions, a thorough revision of the conjunctival sac, and, based on the results of the examination, selects a reliable treatment strategy (therapeutic or surgical). Some types of corneal ulcers (ulcer with keratomalacia, descemetocele, penetrating ulcer) are urgent conditions requiring surgical treatment and aggressive postoperative therapy, otherwise there is a risk of loss of vision and even the eyeball.