How does hyaluronic acid benefit eye health. What are the uses of hyaluronic acid in eye care products. Why is hyaluronic acid important for maintaining healthy eyes as we age. How can hyaluronic acid supplements support vision and eye function.

The Discovery and Importance of Hyaluronic Acid for Eyes

In 1934, German biochemist Dr. Karl Meyer made a groundbreaking discovery when he first identified hyaluronic acid (HA) in a cow’s eyeball. This finding revealed that HA forms the central part of the eye, giving it shape and serving several vital functions. But what exactly is hyaluronic acid, and why is it so crucial for eye health?

Hyaluronic acid is a long chain of carbohydrates found throughout the body. This remarkable molecule has an incredible ability to bind with water, holding up to 1000 times its weight. In fact, research shows that just one gram of hyaluronic acid can hold as much as six liters of water. This water-binding property gives HA its gel-like consistency, which plays a significant role in maintaining moisture in various parts of the body, including the skin, joints, and eyes.

The Role of Hyaluronic Acid in Eye Structure and Function

In the eyes, hyaluronic acid serves several critical purposes:

• Comprises 95% of the fluid inside the eye
• Supports the health of ocular structures like the cornea and retina
• Aids in shock absorption
• Helps transport nutrients throughout the eye
• Maintains optimal fluid levels necessary for proper eye function

Given its importance, it’s no surprise that a decline in hyaluronic acid production can lead to various eye issues. As we age, our bodies gradually lose the ability to produce and retain HA. Research indicates that after age 50, the eyes may lose up to 50% of their capacity to produce the hyaluronic acid needed for optimal performance. This reduction can result in symptoms such as dryness, irritation, redness, and sensitivity – all indicators that the eye lacks this vital fluid.

The Science Behind Hyaluronic Acid’s Effectiveness in Eye Care

Why is hyaluronic acid so effective in eye care products? The answer lies in its unique properties and how they interact with the delicate structures of the eye.

Chemical Structure and Water-Binding Properties

Hyaluronic acid is a glycosaminoglycan, a type of long, unbranched polysaccharide. Its chemical structure allows it to form hydrogen bonds with water molecules, enabling it to hold vast amounts of water relative to its mass. This property is what gives HA its gel-like consistency and makes it an excellent moisturizer and lubricant.

Biocompatibility with Eye Tissues

The human body naturally produces hyaluronic acid, making it highly biocompatible with eye tissues. This compatibility means that when used in eye drops or other ophthalmic applications, HA is less likely to cause irritation or adverse reactions compared to synthetic alternatives.

Viscoelastic Properties

Hyaluronic acid solutions exhibit both viscous and elastic properties, a characteristic known as viscoelasticity. This quality allows HA-based eye drops to spread evenly over the eye surface and remain in place longer than water-based solutions. The result is prolonged lubrication and protection for the eye.

Hyaluronic Acid in Eye Drops: Beyond Simple Relief

The unique properties of hyaluronic acid make it an excellent ingredient for artificial tears and eye drops. But how does it work, and what benefits does it offer beyond basic relief?

Extended Moisture Retention

Due to its gel-like consistency, hyaluronic acid in eye drops can remain on the eye’s surface for longer periods compared to traditional artificial tears. This extended retention time provides longer-lasting moisture and protection for the eyes.

Protective Barrier Formation

As hyaluronic acid spreads across the eye’s surface, it forms a protective barrier that helps shield the delicate tissues from environmental irritants and reduces water evaporation from the tear film.

Support for Healing and Repair

Beyond its lubricating properties, hyaluronic acid has been shown to support the healing of corneal wounds and promote overall eye health. It can help stimulate the production of natural tears and support the regeneration of epithelial cells on the eye’s surface.

Versatility in Ophthalmic Applications

Hyaluronic acid’s unique properties make it useful not only in over-the-counter eye drops but also in more specialized ophthalmic applications. For instance, it’s used during eye surgeries to protect sensitive tissues and maintain proper eye shape during procedures.

Hyaluronic Acid Supplements for Eye Health

While topical applications of hyaluronic acid can provide immediate relief and protection for the eyes, oral supplements may offer additional benefits for long-term eye health. How do these supplements work, and what advantages do they offer?

Internal Support for Eye Structures

Oral hyaluronic acid supplements can help support the body’s natural production of HA, potentially benefiting not just the eyes but also other tissues that rely on this important molecule.

Combination with Other Eye-Supporting Nutrients

Many hyaluronic acid supplements for eye health, such as Hyalogic’s Hylavision, combine HA with other beneficial ingredients:

• Lutein and Zeaxanthin: These antioxidants help filter out harmful light rays and support retinal and macular health.
• Bilberry: This powerful antioxidant promotes healthy eye circulation, supports the eye against strain, supports collagen production, and may even improve night vision.
• Vitamins A, C, E, and Zinc: These nutrients play crucial roles in maintaining overall eye health and function.

Potential for Preventative Care

By supporting the body’s natural HA production and combining it with other eye-supporting nutrients, these supplements may help prevent the onset of age-related eye issues before they start.

The Impact of Aging on Hyaluronic Acid Production and Eye Health

As we age, our bodies’ ability to produce and retain hyaluronic acid diminishes. This decline can have significant implications for eye health. But what exactly happens, and how can we address these age-related changes?

Reduction in HA Production

Research indicates that after age 50, the eyes may lose up to 50% of their ability to produce the hyaluronic acid needed for optimal performance. This reduction can lead to various eye issues, including:

• Increased dryness and irritation
• Reduced tear film stability
• Decreased shock absorption within the eye
• Slower healing of corneal wounds

Changes in Tear Film Composition

The tear film, which plays a crucial role in maintaining eye health and clear vision, also changes with age. These changes can include:

• Decreased tear production
• Alterations in the lipid layer of the tear film
• Reduced mucin production

All of these factors can contribute to dry eye syndrome and other age-related eye issues.

Strategies to Combat Age-Related HA Decline

While we can’t stop the aging process, there are several strategies to help maintain eye health as we age:

1. Regular use of hyaluronic acid eye drops to supplement natural tear production
2. Taking oral HA supplements to support internal production
3. Maintaining a diet rich in antioxidants and eye-supporting nutrients
4. Protecting eyes from UV radiation and other environmental stressors
5. Regular eye check-ups to monitor eye health and address issues early

Hyaluronic Acid in Ophthalmic Surgery and Advanced Eye Care

Beyond its use in over-the-counter eye drops and supplements, hyaluronic acid plays a crucial role in various ophthalmic surgical procedures and advanced eye care treatments. How is HA used in these contexts, and what benefits does it offer?

Viscoelastic Agents in Cataract Surgery

During cataract surgery, hyaluronic acid-based viscoelastic agents are used to:

• Maintain the shape of the eye during lens removal and replacement
• Protect delicate eye tissues from surgical instruments
• Create space within the eye for better visibility and maneuverability

Corneal Transplantation

In corneal transplant procedures, HA-based solutions can help:

• Protect the donor cornea during storage and transportation
• Maintain corneal hydration during the transplant procedure
• Support post-operative healing and integration of the transplanted tissue

Treatment of Severe Dry Eye

For patients with severe dry eye syndrome, specialized hyaluronic acid treatments may be used, including:

• High-concentration HA eye drops for extended relief
• HA-based gels or ointments for overnight protection
• Punctal plugs made with or coated in hyaluronic acid to retain tears

Regenerative Medicine Applications

Emerging research is exploring the potential of hyaluronic acid in regenerative medicine for eye conditions, including:

• HA-based scaffolds for corneal tissue engineering
• Delivery systems for sustained release of ophthalmic medications
• Support for stem cell therapies in retinal regeneration

The Future of Hyaluronic Acid in Eye Care: Emerging Research and Innovations

As our understanding of hyaluronic acid and its role in eye health continues to grow, researchers and innovators are exploring new ways to harness its potential. What exciting developments are on the horizon for HA in eye care?

Advanced Drug Delivery Systems

Researchers are developing innovative drug delivery systems using hyaluronic acid as a carrier for ophthalmic medications. These systems aim to:

• Improve drug absorption and bioavailability
• Extend the duration of drug action
• Reduce the frequency of medication administration
• Minimize side effects by targeting specific eye tissues

Nanoparticle Formulations

Hyaluronic acid-based nanoparticles are being explored for various ophthalmic applications, including:

• Targeted delivery of anti-inflammatory and anti-angiogenic drugs
• Gene therapy for inherited retinal disorders
• Enhanced penetration of drugs through ocular barriers

Combination Therapies

Researchers are investigating the potential synergistic effects of combining hyaluronic acid with other beneficial compounds, such as:

• Antioxidants for enhanced protection against oxidative stress
• Growth factors to promote tissue regeneration
• Anti-inflammatory agents for improved management of ocular surface diseases

Bioengineered HA Variants

Scientists are working on developing modified versions of hyaluronic acid with enhanced properties, including:

• Increased resistance to enzymatic degradation for longer-lasting effects
• Improved cross-linking capabilities for better retention on the ocular surface
• Tailored molecular weights for specific ophthalmic applications

Personalized Eye Care Solutions

As personalized medicine advances, there’s potential for developing customized hyaluronic acid formulations based on individual patient needs, considering factors such as:

• Specific eye conditions
• Age-related changes in HA production
• Environmental factors affecting eye health
• Genetic predispositions to certain eye disorders

These emerging research areas and innovations hold great promise for the future of eye care, potentially offering more effective, targeted, and personalized solutions for maintaining and improving eye health. As we continue to unlock the full potential of hyaluronic acid, we may see revolutionary advancements in how we prevent, treat, and manage a wide range of eye conditions.

Hyaluronic Acid for Eye Health • Hyalogic® Animal Health

Here’s a question you don’t hear every day: What do your joints and eyes have in common?

The answer is right before your eyes – literally! Hyaluronic Acid (HA) was first discovered in a cow’s eyeball in 1934, by German biochemist Dr. Karl Meyer. Meyer eventually discovered that it was this property that makes up the central-most part of the eye, thus forming its shape and serving a number of other purposes that are vital to proper function.

Hyaluronic Acid is essentially a long chain of carbohydrates found throughout the body—a sugary molecule which seeks out and binds to water, able to hold up to about 1000 times its weight! (Translation: this study[1] reports that one gram of hyaluronic acid is capable of holding as much as six liters of water.) This is what creates gelatin-like HA, which plays a significant role in maintaining moisture in the skin, eyes, and that’s right…your joints. The synovial fluid that cushions your bones and absorbs shock is actually composed of hyaluronic acid.  

While it serves many functions in the body, let’s go back to where it all started: the eye. What does it actually do, and how can one support their eye health with Hyaluronic Acid?

Because the eyes rely on optimal fluid levels in order to function—it’s no wonder that hyaluronic acid is what makes up 95% of the fluid inside the eye, supporting the health of ocular structures such as the cornea and retina. With its super-ability to bind to moisture, it also aids in absorbing shock and transporting nutrients.

As you age, however, the body begins to lose its ability to produce and retain hyaluronic acid. Research indicates that after age 50, the eyes could lose up to 50 percent of their ability to produce the HA needed for optimal performance. Dryness, irritation, redness and sensitivity are all indicators that the eye is lacking in this vital fluid. It’s when these functions are compromised that vision becomes affected.

Hyaluronic Acid in Eye Drops: Beyond Relief

The properties of HA lend themselves incredibly well for use in artificial tears. Remember the gelatin-like substance? Since it is found in the vitreous fluid of the eyes, the unique viscosity of HA allows eyedrops to remain on the eye longer. This can provide longer-lasting moisture and protection. Hyaluronic acid eye drops can even be used during ophthalmic surgery to protect sensitive tissues.

Hyaluronic acid not only acts as a lubricant, but it has been known to actually support countering issues caused by aging and external factors (such as UV radiation), as well as promote healthy eye structure.

But how does HA do it?

Hylavision: Support from Within

Much like the rest of the body, there are certain key nutrients we need to support our eyes’ health. That’s why Hyalogic offers Hylavision, a consumable supplement designed for the upkeep of proper eye health. This supplement is composed of eye-targeting antioxidants and nutrients that we may be missing in our diet. With vitamins A, C, E, and Zinc, Hylavision also includes:

• Lutein and Zeaxanthin: These antioxidants work to filter out and absorb harmful light rays, as well as support the overall retinal and macular health of the eye.
• Bilberry: Another powerful antioxidant, this ingredient promotes healthy eye circulation, supports the eye against strain, supports collagen, and can even support night vision.  

Hyalogic not only offers natural and effective topical products like HA skincare and eye drops, it also offers a way to support preventing the onset of issues before they start. And with your eyesight, it’s comforting to know HA can provide support through drops or supplements.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970829/

What is hyaluronic acid and how does it work in eye drops?

What is hyaluronic acid and how does it work in eye drops?
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Hyaluronic acid (hyaluron, sodium hyaluronate, hyaluronan) is widely spread in the human body. Hyaluronic acid has an important function in connective tissue, skin, intervertebral discs, joints and nerve tissue and is also contained in the tear fluid. Hyaluronic acid is able to bind very large amounts of water and, when dissolved in water, acts as a lubricant.

Hyaluronic acid is built up and constantly catabolized by the body. In the outer layer of the cornea of the eye (epithelium) about half of the hyaluronic acid present there is broken down daily and replaced by newly formed hyaluronic acid. The cornea is not supplied by blood vessels. The hyaluronic acid in the spaces between the cells therefore plays a decisive role in supplying the cornea with nutrients and disposing of metabolic products, as well as in cell differentiation, cell renewal and wound healing.

From a chemical point of view, hyaluronic acid is a chain-like arrangement of sugar molecules. A hyaluronic acid chain can consist of 500 to 100,000 chain links.

The length of the hyaluronic acid chains determines their physical properties and their biological function.

The healthy tear film combines a high viscosity (viscous) when the eye is open with a low viscosity (thin) when the eye is blinking. Thus, on the one hand it remains on the eye surface for a long time, on the other hand it ensures a smooth gliding of the eyelid over the eye surface and prevents blurred vision (streaky vision) after the blink.

Only eye drops containing hyaluronic acid with an extremely long chain length (Hylan A) give the drops flow properties similar to those of the natural tear film, reduce the friction between the eyelid and the eye surface during the blink of the eye the most, remain on the eye surface the longest after the drops have been applied and bind the most water. In addition, very long hyaluronic acid chains prevent inflammation of the eye and the eyelid margins and contribute to the healing of existing inflammation.

Eye drops with medium chain length hyaluronic acid behave neutrally with regard to inflammation, while short hyaluronic acid chains can contribute to an intensification of the inflammation.

Of all hyaluronic acid eye drops, Comfort Shield^® eye drops contain the hyaluronic acid with the longest chain length (Hylan A, approx. 3 MDa), while Comfort Tears^® eye drops contain medium chain hyaluronic acid (approx. 2 MDa).

In eye drops hyaluronic acid increases the viscosity of the solution). In eye drops with hyaluronic acid of a very long chain length (Hylan A), the molecular chains can become entangled with each other when the eye is open. These eye drops therefore remain on the surface of the eye for up to more than an hour.

When the eyelid is blinking, the long hyaluronic acid molecules arrange themselves in parallel, making these eye drops just as thin as eye drops with hyaluronic acid of shorter chain length.

Only the hyaluronic acid (Hylan A) used in Comfort Shield^® offers optimum effectiveness and tolerability.

Further information on the flow behaviour of commercially available hyaluronic acid eye drops and the role of hyaluronic acid in maintaining the physiological balance of the eye is provided in the enclosed technical articles.

Hyaluronic Acid Eye Drops – What you should know about their rheological properties
Dr. Wolfgang Müller-Lierheim: 

Tear substitutes – News about hyaluronic acid
Dr. Wolfgang Müller-Lierheim:

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Hyaluronic acid and vision: use in eye diseases

Table of contents

Functions of hyaluronic acid in the human body

How is hyaluronic acid used in medicine?

The use of hyaluronic acid in ophthalmic operations

Treatment and prevention of dry eye syndrome using hyaluronic acid

Solution “Gylan” to eliminate dry eyes

Hyaluronic acid is a polymer macromolecule that is a component of the vitreous body of the eyeball, skin, and connective tissues. In a liquid state, they are present in saliva, cerebrospinal and synovial fluid, tear fluid.

Being a natural component of the body, hyaluronate is involved in almost all biological processes, so its role for human health is invaluable.

Functions of hyaluronic acid in the human body

One of the most important properties of hyularonate is the ability to bind and retain water molecules. 1 gram of acid absorbs about 3 liters of water and delivers them to those areas that need moisture. In addition, hyaluronic acid ensures the growth and division of cells, the transport of oxygen contained in the blood to the tissues.

Hyaluronic acid affects the condition of the joints and synovial fluid, maintains turgor and skin elasticity, retaining moisture in the deep layers of the epidermis and dermis, stimulating the production of its own collagen and elastin.

The rate of human aging and the health of all organs largely depends on the amount of hyaluronic acid, more precisely, on the balanced dynamics of its own synthesis and decay. Various biological processes can change this balance, but the main danger is UV radiation, which damages skin cells and causes a decrease in hyaluronate production.

As is known, the influence of ultraviolet light triggers carcinogenesis – the process of tumor development. Hyaluronic acid does not allow cells to thicken and “crowd”, it is an additional barrier to the onset of the tumor process.

How is hyaluronic acid used in medicine?

Synovial fluid endoprostheses. In osteoarthritis, a more physiological alternative to surgery is the introduction of a liquid preparation based on hyaluronic acid. The endoprosthesis is identical to natural synovial fluid, restores the viscosity of natural lubrication and joint mobility.

Smoothing of skin tissues and wrinkles. Hyaluronate rejuvenation effect is widely used in cosmetic surgery. Various doses of hyaluronic acid are injected into problem areas or in the form of long threads. Thus, the synthesis of one’s own acid is stimulated, and depending on the chosen technique, wrinkles can be removed, the shape of the lips can be changed, and the face can be corrected.

GERD. Hyaluronic acid in combination with chondroitin sulfate helps to restore the esophageal mucosa, has an anti-inflammatory effect, and promotes the healing of ulcers.

Perspectives in the treatment of cancer. The uniqueness of hyaluronate is that it prevents the formation of primary tumors, it is contained in anticancer drugs.

Application of hyaluronic acid in ophthalmic operations

Hyaluronate is found in the vitreous body of the eye and adjacent blood vessels. Its molecules bind to water molecules, due to which the tear is retained on the surface of the eyeball. Being a key component of the lacrimal fluid, the substance prevents the drying of the cornea, pathological changes in the internal structures of the eye. It is used during surgical manipulations to create an optimal environment and protect the eyeball from accidental injury.

Treatment and prevention of dry eye syndrome using hyaluronic acid

HA is the main active ingredient of the artificial tear preparation, which is practically the only effective non-surgical treatment for dry eye syndrome. Eye drops increase the stability of the tear film, improve the composition of the tear fluid, thereby stimulating the restoration of damaged areas of the cornea.

The use of eye drops such as artificial tears significantly reduces the risk of developing dry eye syndrome, ophthalmic complications. For people at risk for DES – gamers, office workers, workers in hazardous industries, truck drivers, elderly patients – preparations with hyaluronic acid help to quickly relieve fatigue and redness of the eyes, increase the resistance of the visual system to stress and external factors.

Hylan solution to eliminate dry eyes

Gilan moisturizing drops is a preparation with hyaluronic acid of different concentrations. It has a preventive and therapeutic effect in case of dry eyes caused by overwork, wearing contact lenses, taking anti-inflammatory drugs.

“Gylan” is suitable for athletes, motorists, gamers, office workers and the elderly, maintaining the natural moisture of the eyes throughout the day.

Hyaluronic acid: application in ophthalmology and treatment of dry eye syndrome | Egorov E.A.

Summary
This review describes the use of HA in the anterior segment of the eye, in particular in the treatment of dry eye syndrome, as well as in contact lenses and their care systems.

This review describes the use of HA in the anterior segment of the eye, in particular in the treatment of dry eye syndrome, as well as in contact lenses and their care systems.
Key words: hyaluronic acid, dry eye syndrome, contact lenses.

Abstract
Hyaluronic acid: it’s usage in ophthalmology and
in treatment of dry eye syndrome
E.A. Egorov

RNIMU named after N. I. Pirogov
Department of Ophthalmology named after acad. A.P. Nesterov
This review describes the effectiveness of Hyaluronic acid in treatment of dry eye syndrome and its usage in contact lens and solutions for contact lenses.
Key words: hyaluronic acid, dry eye syndrome, contact lenses.

Hyaluronic acid (HA) is a natural polysaccharide with unique viscoelastic and hygroscopic properties. These characteristics determine the participation of HA in many processes in the human body [1–3]. HA is used in ophthalmic practice: in cataract surgery to optimize the installation of an intraocular lens, in vitreoretinal surgery. HA is included in the material of contact lenses to improve their wearing comfort [4].
Dry eye syndrome
In recent decades, the importance of the dry eye problem has increased. This is due to the intensive development of both modern ophthalmic surgery and pharmacotherapy of eye diseases.
According to ARVO, in 2012, dry eye syndrome ranked third in the number of published studies, second only to glaucoma and age-related macular degeneration. According to Reddy, the prevalence of the disease reaches 11–17% among the entire population [17]. The quality of life of patients with moderate dry eye syndrome is equivalent to that of patients with moderate angina [18].
The most numerous group is young patients (20–45 years old), in whom the “dry eye” syndrome is associated with excessive evaporation of the lacrimal fluid (office syndrome, wearing contact lenses, refractive surgery, transient tearing disorders after infectious and inflammatory processes, etc.). .) (Fig. 1). In the group of patients older than 55 years, the disease is caused by endocrine changes leading to impaired tear formation, and is called Sjögren’s syndrome [19].].
The result of tear replacement therapy should be the elimination of discomfort in patients. Preparations for the treatment of dry eye syndrome should have a physiological mechanism of action. It is these characteristics that are inherent in preparations based on HA.
HA production method for use
in pharmacotherapy of “dry eye” syndrome
In many ways, the tolerance of HA-based tear substitutes is determined by the method of production. Previously, methods have been used to obtain HA from the vitreous body of a cow’s eye and a rooster’s comb. The disadvantages of these production methods were their high cost and the presence of protein impurities in the final product, which led to a large number of allergic reactions to the drug [5]. Modern HA production is based on a fermentation process using bacteria (Streptococcus equi and Streptococcus zooepidemicus). HA obtained in this way has a higher degree of purification, which explains the better tolerance of HA by patients [1, 2].
Properties of HA that determine its use
for the treatment of dry eye syndrome
HA is a natural polymer and belongs to the group of polysaccharides, which are also called connective tissue polysaccharides, mucopolysaccharides, or glycosaminoglycans [1, 3, 7]. These polysaccharides affect the distribution of water in the connective tissue, incl. and stroma of the cornea [6, 8]. In terms of physicochemical properties, HA can change its structure depending on pH (acidity or alkalinity), salt concentration, and the effect of pressure gradient [9]. An increase in the pressure and temperature gradient leads to a decrease in the viscosity of the solution. Similarly, due to the alkaline pH value, a more mobile molecular structure is formed [1, 10].
In addition to viscoelastic properties, HA has a pronounced ability to retain water. This property may be associated with the presence of a large number of hydroxyl groups, which leads to the formation of hydrogen bonds [1, 7, 11–14]. Researchers claim that HA can hold an amount of water that is 1000 times its own mass [7, 24]. Normally, in the human body, HA is found in the extracellular matrix of connective tissue in the skin and synovial fluid [1–3]. HA is also determined in the vitreous body, lacrimal gland, corneal epithelium, and conjunctiva of the eye [1–3, 15, 16].
It is assumed that HA has anti-inflammatory properties and is involved in the processes of cell functioning, such as proliferation, differentiation, and migration [20]. It has been proven that HA stimulates the migration of epithelial cells, which promotes the healing of corneal wounds [21–23].
Numerous studies have demonstrated the effectiveness of HA in the symptomatic treatment of dry eye [3, 13, 25–29]. At the same time, a balanced concentration of HA in the composition of the tear replacement drug is of great importance.
In a controlled, double-blind, cross-over study in 20 patients with severe dry eye, HA 0.1%, HA 0.2%, or placebo was administered 6 times a day for 14 days. The purpose of this study was not only to evaluate the effectiveness of HA in severe dry eye, but also to determine the most effective concentration of the drug. There were no significant differences between the 0.1% HA and placebo groups in terms of Schirmer test, Tear Break Time (TBRT) and Rose Bengal stain test results. However, when comparing the higher concentration of 0.2% HA solution with placebo, there was a significant difference in the results of rose Bengal staining in the group of patients treated with HA (P<0.005). This group also showed a more pronounced increase in RTSP compared with placebo (P < 0. 005) [29].
In a comparative randomized, blind, placebo-controlled study involving 12 patients, RTRP was assessed when prescribing 0.05%, 0.1%, or 0.3% HA solution. VRSP measurements were carried out before instillation of eye drops, as well as after 5, 15, 30, 60, 120, and 180 minutes. after her. A significant increase in RTSP was found for HA concentrations of 0.1% and 0.3% [25].
To assess subjective tolerance and VRSP in patients with tear film lipid deficiency, 10 patients were instilled with 0.18% HA solution in one eye and 0.3% hydroxypropyl methylcellulose solution in the other. Both treatments resulted in significant increases in RTSP at 15, 30, and 60 minutes. after instillation compared with baseline (P<0.05), however, the increase in RTSP in the group treated with HA was significantly higher at 30 and 60 minutes. observations (P=0.04 and P=0.005, respectively) [28]. Thus, taking into account the results of these studies, a concentration of 0.1–0.3% can be considered a therapeutically significant concentration of HA.
Returning to the topic of the prevalence of dry eye syndrome, it should be noted that it occurs both in young people and in the elderly. When prescribing therapy, it is necessary to take into account the nature of the course of the disease in each of these groups. So, in the group of young patients with excessive evaporation of the lacrimal fluid, the symptoms are predominantly transient. In this group, the use of a higher concentration of HA (0.2-0.24%) is optimal for a quick but short-term relief of symptoms. In international clinical practice, Artelac Splash (Bausch + Lomb, USA) has proven itself well – a preservative-free drug with a content of 0.2 and 0.24% HA. The release form of this drug is different – both in a standard vial and in multidose.
In the older age group (over 55 years) with endocrine disorders of tear secretion, the course of the dry eye syndrome is chronic. In this group, it is possible to recommend the use of drugs with a lower concentration of HA – from 0. 15% Oxial (Bausch + Lomb, USA).
Conclusion
HA plays an important role in the physiology of the eye. The unique physicochemical properties of HA provided the basis for its effective use in the symptomatic treatment of dry eye syndrome. Taking into account the prevalence of this syndrome (both young and elderly patients), recommendations were made for the use of various concentrations of HA in the composition of tear substitutes. Thus, for faster relief of transient symptoms, the administration of HA at a concentration of 0.2–0.24% Artelac Splash (Bausch + Lomb, USA) is indicated. In the group with a chronic course of the “dry eye” syndrome (age over 55 years), long-term use of drugs with a lower concentration of HA – 0.15% Oxial, (Bausch + Lomb, USA) is possible.

Literature
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