On this page
- What is hyaluronic acid?
- How does it work on the eye surface?
- What does research say?
- Hylo-Comod as an example
- Why is it important for the drops to be preservative-free?
- How to use lubricating drops correctly
- Drop, gel or lipid-based product?
- Lubricating drops and contact lenses
- Side effects
- When are lubricating drops not enough?
If you searched for "Hylo-Comod", you have probably heard about these drops, or you are already using them and want to understand what they do. On this page we explain what hyaluronic acid is, what research shows about it, how to use lubricating drops correctly, and when it is worth looking for the cause of the dryness rather than just adding more drops.
What is hyaluronic acid?
Hyaluronic acid (in drops usually in the form of its salt, sodium hyaluronate) is a substance the body makes itself. It is found in the skin, the joints and inside the eye, and it can bind a large amount of water.
In eye drops it is used as a substance that thickens the drop and holds moisture on the eye surface. It is considered one of the common ingredients in artificial tears.
How does it work on the eye surface?
Hyaluronic acid has several properties that suit this role:
- It binds water: it helps keep a layer of fluid on the cornea and the conjunctiva for longer than a simple saline solution.
- Its viscosity changes with movement: during a blink it becomes thinner and spreads easily, and between blinks it is thicker and stays on the eye. That is why it usually does not blur vision like a thick gel.
- It clings to the eye surface: it attaches to the mucus layer (mucin) on the eye surface, and so stays there for longer.
There is also laboratory work suggesting that it may support healing of the top layer of cells of the cornea, but the clinical significance of this is not yet fully clear.
What does research say?
A Cochrane systematic review of over-the-counter artificial tears (Pucker and colleagues, 2016) found that these drops may relieve symptoms of dryness, but the quality of the evidence comparing different types was low, and it was not shown that one type is clearly better than the others.
A meta-analysis that focused on drops with hyaluronic acid (Yang and colleagues, 2021) found that they improve symptoms and signs of dryness, but the differences between them and other artificial tears were small or inconsistent. In other words: hyaluronic acid is a reasonable and accepted ingredient, but it is not a magic solution.
Hylo-Comod as an example
Hylo-Comod is one example among several lubricating drops that contain sodium hyaluronate. It comes in a preservative-free multi-dose bottle, which is designed to reduce the risk of the drops becoming contaminated after opening. This makes it possible to use preservative-free drops from a bottle too, and not only from single-dose units.
There are other products with hyaluronic acid in different concentrations, and some combine it with other ingredients, such as trehalose, carbomer or lipids. No single product suits everyone. The right choice depends on the type of dryness, how often you use the drops, sensitivities and personal comfort.
The name appears here to explain what type of product it belongs to, not as a preference over other products. If you are happy with the drops you use and they relieve your symptoms, there is no reason to change them. If they do not help enough, the important question is usually not which drop, but what is causing the dryness.
Why is it important for the drops to be preservative-free?
Preservatives, and especially benzalkonium chloride (BAK), prevent bacteria from growing in the bottle, but with frequent use they may damage the cells of the eye surface and make inflammation worse. People who use drops more than a few times a day, who also use glaucoma drops, who wear contact lenses or who are recovering from surgery will usually benefit from preservative-free drops. More on this topic is on the preservative-free eye drops page.
How to use lubricating drops correctly
- Wash your hands before putting in drops.
- Tilt your head slightly back, gently pull down the lower eyelid, and put one drop into the pocket that forms.
- Do not touch the eye, the lashes or the skin with the tip of the bottle.
- Close your eye gently for about half a minute. Do not blink hard, so that the drop is not squeezed out.
- If you use several types of drops, wait a few minutes between them. Lubricating drops are usually given after medicated drops.
- Check in the leaflet how long the bottle can be used after opening, and whether the product is suitable for use with contact lenses.
If you need a feeling of moisture at night too, the eye doctor may suggest a thicker gel or ointment before sleep. They blur vision for a short time, so they are less suitable for daytime.
Drop, gel or lipid-based product?
Artificial tears differ from each other mainly in thickness and composition. Thin drops are convenient to use during the day and do not blur, but their effect is shorter. Thick gels stay on the eye longer, but blur vision for a few minutes. Drops with hyaluronic acid are usually in the middle: thick enough to hold moisture, and thin enough not to interfere with vision.
When the dryness is mainly due to increased evaporation, because the meibomian glands are not working well, products that contain lipids may suit some people, because they try to imitate the missing oily layer. There is no single rule that suits everyone, and sometimes you need to try two or three products before finding the right one.
Lubricating drops and contact lenses
Contact lens wearers often suffer from dryness, because the lens breaks up the tear film and increases evaporation. Some drops with hyaluronic acid are labelled as suitable for use with lenses, and some are not. Check the leaflet before using them. If you have to take your lenses out early because of burning, that is a sign that it is worth having the dryness checked, not just adding drops.
Side effects
Lubricating drops with hyaluronic acid are well tolerated by most people. Sometimes there is brief blurring straight after putting them in, or a sticky feeling on the lashes. Rarely, irritation or redness appears, suggesting sensitivity to one of the ingredients. If this happens, stop using them and consult a pharmacist or doctor.
When are lubricating drops not enough?
Lubricating drops add fluid to the eye surface. But in most people with dry eye, the problem is not just a lack of fluid. The most common cause is meibomian gland dysfunction (MGD, the oil glands in the eyelid margins), which makes the tears evaporate too quickly. In this situation, a drop with hyaluronic acid will bring short-term relief, but the glands will still not be working properly.
Signs that it is worth being examined:
- You use drops more than four or five times a day and still have symptoms.
- The relief lasts only a few minutes.
- Your eyelids are red, sticky in the morning, or there are scales at the base of the lashes.
- Your vision blurs and changes during the day.
- You have a general medical condition linked to dryness, such as Sjögren's syndrome.
An examination by a dry eye specialist checks the stability of the tears, their amount and the condition of the meibomian glands and eyelid margins (see dry eye testing). Depending on the findings, treatment of the cause can be added, for example meibomian gland expression or IPL treatment when the glands are blocked, or punctal plugs when there are not enough tears. You will find an overall picture of the topic in the guide Dry eye: what it is and when you need a specialist.
Want a basic explanation first?For basic information on artificial tears: the guide on the Mitzmutz site
Frequently asked questions
Is Hylo-Comod a medicine?
No. It is a lubricating drop (an artificial tear) that contains hyaluronic acid. It relieves symptoms of dryness, but it does not treat the cause, such as blocked meibomian glands or inflammation.
Are drops with hyaluronic acid better than other lubricating drops?
Research shows that they help relieve dryness, but the differences between them and other types of artificial tears are not consistent. The right drop is the one that relieves your symptoms and is comfortable for you to use, preferably preservative-free.
Can I use these drops with contact lenses?
Some drops are suitable for use with contact lenses and some are not. Check this in the leaflet of the specific product, or ask the pharmacist or the eye doctor.
How many times a day can I use them?
Preservative-free lubricating drops can usually be used as needed, following the instructions in the leaflet. If you need them many times a day and still have symptoms, it is worth being examined to find out what is causing the dryness.
Home care not enough? We can look into it.
At the dry eye clinic in Haifa we find out what is causing the dryness and build a personal treatment plan.
Sources
- Yang YJ, Lee WY, Kim YJ, Hong YP. A Meta-Analysis of the Efficacy of Hyaluronic Acid Eye Drops for the Treatment of Dry Eye Syndrome. Int J Environ Res Public Health. 2021;18(5):2383.
- Pucker AD, Ng SM, Nichols JJ. Over the counter (OTC) artificial tear drops for dry eye syndrome. Cochrane Database Syst Rev. 2016;2:CD009729.
- Jones L, Downie LE, Korb D, et al. TFOS DEWS II Management and Therapy Report. Ocul Surf. 2017;15(3):575-628.
- Baudouin C, Labbé A, Liang H, Pauly A, Brignole-Baudouin F. Preservatives in eyedrops: the good, the bad and the ugly. Prog Retin Eye Res. 2010;29(4):312-334.
The information on this site is general only. It is not medical advice and does not replace an examination by an eye doctor.