What are the ingredients in tear drops? A comprehensive guide

October 11, 2025 •

5 min read

According to a systematic review published in Dove Medical Press, artificial tears can effectively improve dry eye symptoms with regular use. Understanding what are the ingredients in tear drops is the first step toward selecting the right product for your specific needs, whether for temporary relief or chronic irritation.

Quick Summary

This article explores the key components of over-the-counter tear drops, including lubricating and lipid-based active agents, inactive additives like preservatives, buffers, and osmoprotectants, and how each functions to provide eye relief.

Key Points

Demulcents are core lubricants: Ingredients like carboxymethylcellulose (CMC), polyethylene glycol (PEG), and glycerin act as demulcents to add moisture and increase the eye drop's staying power on the eye's surface.
Lipids target evaporative dry eye: Formulations with emollients such as mineral oil and castor oil are designed for evaporative dry eye by strengthening the tear film's oily layer and preventing rapid tear evaporation.
Vasoconstrictors cause rebound redness: Redness-relieving drops containing ingredients like tetrahydrozoline should be used sparingly, as their effect is temporary and prolonged use can worsen redness.
Preservatives can irritate sensitive eyes: Preserved drops, which come in multi-dose bottles, can irritate sensitive eyes, especially with frequent use. Preservative-free (PF) drops are recommended for chronic dry eye.
Osmoprotectants protect eye cells: Ingredients such as erythritol and L-carnitine help protect eye cells from the damaging effects of a high salt concentration in tears, a common issue in dry eye.
Viscosity varies based on need: The viscosity of a drop determines its longevity on the eye. Thicker gel drops or ointments provide longer relief but may blur vision temporarily, making them suitable for nighttime use.
Ingredient combinations can be more effective: Some studies show that combination formulas, particularly those with multiple active ingredients, can be more effective than single-ingredient drops.

Most artificial tear products, or lubricating eye drops, contain a combination of active and inactive ingredients designed to supplement or mimic natural tears. The precise formulation determines the product's effectiveness, viscosity, and suitability for different types of dry eye conditions. While the primary goal is to moisturize and protect the eye's surface, not all tear drops are created equal.

Core Active Ingredients: Lubricants (Demulcents)

Demulcents are the primary active ingredients in most artificial tear formulations, serving to soothe irritated mucous membranes, provide lubrication, and increase tear viscosity. This helps the drops remain on the eye's surface for a longer period, providing extended relief. Common demulcents include:

Carboxymethylcellulose (CMC): A popular thickening agent that binds to the eye's surface, making tears more viscous and stable. It is found in many products, including various Refresh formulations.
Polyethylene Glycol (PEG) & Propylene Glycol (PG): These demulcents work together to create a protective shield over the eye, providing lubrication and moisturizing relief. They are common in Systane products. PG also has humectant properties, allowing it to hold more water.
Glycerin: A humectant and lubricant that attracts and holds moisture, supporting cell growth and protecting the ocular surface against the damaging effects of high salt concentration. It is often combined with other demulcents.
Hyaluronic Acid (HA) / Sodium Hyaluronate: A naturally occurring substance that binds large quantities of water, acting as an excellent lubricant and humectant. It helps to stabilize the tear film and can also aid in corneal wound healing.
Povidone: A polymer demulcent that integrates with the existing oily layer of the tear film, helping to reduce tear evaporation.
Hydroxypropyl Methylcellulose (HPMC): A hydrophilic polymer that coats and protects the eye's surface, functioning as a thickening and gelling agent.

Ingredients for Evaporative Dry Eye: Lipids and Emollients

For people with evaporative dry eye, where tears evaporate too quickly due to a poor lipid layer, specific formulations containing emollients are necessary. These ingredients help to supplement the tear film's oily layer and reduce evaporation. Examples include:

Mineral Oil & White Petrolatum: These oily ingredients are frequently used in thicker eye ointments, especially for overnight relief. They seal in moisture but can cause blurred vision, making them unsuitable for daytime use.
Castor Oil & Flaxseed Oil: Found in some advanced formulations, these ingredients serve as emollients to strengthen the lipid layer and combat evaporation.

Inactive Ingredients: Preservatives and Other Additives

Beyond the active ingredients, tear drops contain many inactive compounds that serve specific purposes, such as maintaining sterility and creating a comfortable, pH-balanced solution.

Preservatives: Found in multi-dose bottles, preservatives inhibit the growth of bacteria and prolong shelf life. However, some can cause eye irritation or toxicity with frequent or chronic use, especially for those with sensitive eyes.
- Benzalkonium chloride (BAK): A common, but potentially irritating, preservative.
- Softer Preservatives: Less toxic options include Polyquad® (polyquaternium-1), Purite® (stabilized oxychloro complex), and OcuPure®.
Preservative-Free (PF) Formulations: These drops are ideal for frequent use or sensitive eyes and typically come in single-use vials to prevent contamination.
Buffers & Salts: Ingredients like boric acid, sodium borate, and sodium chloride help maintain the solution's pH and osmolarity, ensuring it is comfortable for the eye.
Osmoprotectants: Compounds like erythritol, L-carnitine, and trehalose help protect dehydrated eye cells from high salt concentrations in tears.

Comparing Tear Drop Ingredients


Ingredient Type	Common Examples	Primary Function	Best For...
Aqueous/Lubricating (Demulcents)	Carboxymethylcellulose (CMC), Polyethylene Glycol (PEG), Propylene Glycol (PG), Glycerin, Hyaluronic Acid	Add moisture, increase viscosity, and protect the eye's surface	General, short-term dry eye relief caused by environmental factors, computer use, or mild irritation
Lipid-Based (Emollients)	Mineral Oil, White Petrolatum, Castor Oil	Supplement the oily layer of the tear film to prevent evaporation	Evaporative dry eye (MGD) and chronic dry eye symptoms, often in thicker formulas or for nighttime use
Redness Relievers (Vasoconstrictors)	Tetrahydrozoline, Naphazoline	Temporarily constrict blood vessels to reduce eye redness	Not recommended for regular dry eye relief. Short-term cosmetic use only, as prolonged use can cause rebound redness and worsen dryness.
Preservative-Free (PF)	Any of the above active ingredients, packaged in single-use vials	Provide lubrication without chemical additives that can cause irritation	Sensitive eyes, chronic dry eye sufferers, contact lens wearers, and those who use drops frequently throughout the day

Redness-Relieving vs. Lubricating Drops

It is crucial to distinguish between lubricating tear drops and redness-relieving drops. While some products market themselves for both, those with vasoconstrictors like tetrahydrozoline or naphazoline only address the symptom of redness by constricting blood vessels. Long-term or overuse can lead to a 'rebound effect' where eyes become even redder when the drops wear off. It is safer and more effective to use lubricating, or artificial tear, drops to treat the underlying cause of irritation, which often results in redness naturally subsiding. For persistent redness, consulting an eye doctor is recommended.

Preservative-Free: A Critical Consideration

For many individuals, particularly those with chronic or severe dry eye, the frequent use of preserved multi-dose drops can lead to irritation and further damage to the eye's delicate surface. Preservatives, especially BAK, are known to have a toxic effect on the ocular surface over time. Preservative-free formulations, which come in small, single-use vials, eliminate this risk and are often recommended by eye care professionals. While typically more expensive, they are a safer and often more comfortable choice for consistent, long-term use.

Conclusion

Choosing the correct tear drop depends on the specific cause of your eye discomfort. By understanding the function of the different ingredients—from lubricating demulcents like CMC and PEG to lipid-based emollients and various inactive additives—you can make a more informed decision. For general irritation, a standard lubricating demulcent may be sufficient. For evaporative dry eye, a lipid-based formula is more effective. And for sensitive eyes or frequent use, a preservative-free option is the safest bet. Always avoid relying on redness-relieving drops for anything other than temporary cosmetic use. If symptoms persist or worsen, consulting an eye care professional is the best course of action for a proper diagnosis and treatment plan.

For more information on eye health and choosing the right products, see the resources available from the American Academy of Ophthalmology.

Frequently Asked Questions

Preserved drops contain chemical additives, such as benzalkonium chloride (BAK) or milder alternatives like Polyquad, to prevent bacterial contamination and extend shelf life. Preservative-free drops, typically sold in single-use vials, do not contain these chemicals and are recommended for sensitive eyes or frequent use to avoid potential irritation.

For evaporative dry eye, which is caused by a deficient oily layer in the tear film, lipid-based emollients are most effective. Look for drops containing mineral oil, castor oil, or flaxseed oil to help prevent tear evaporation. These are often labeled for MGD (Meibomian Gland Dysfunction).

No, redness-relieving drops often contain vasoconstrictors like tetrahydrozoline that only constrict blood vessels for a temporary cosmetic effect. These ingredients do not address the underlying dryness and can cause rebound redness if used regularly, worsening the problem over time.

Inactive ingredients like boric acid and sodium chloride are used to buffer the solution, maintaining a pH and salt balance that makes the drop comfortable and safe for the eye. Other inactive additives might increase viscosity or act as antioxidants.

Osmoprotectants, such as L-carnitine and erythritol, are ingredients added to protect and rehydrate dry eye cells. They work by counteracting the high salt concentrations that can develop in the tear film with dry eye disease, which can cause cell damage.

It is crucial to use eye drops specifically formulated to be used with contact lenses. Many preserved drops are not safe for use with contacts and can cause irritation. Preservative-free solutions are generally the safest option for contact lens wearers.

Thicker gels and ointments, which have a higher viscosity, provide longer-lasting relief by staying on the eye longer. They are often recommended for nighttime use because they can temporarily blur vision. Thinner drops are better for quick, daytime relief.

Hyaluronic acid is a highly effective humectant that can hold a large amount of water, providing excellent lubrication. Its shear-thinning properties mimic natural tears, making it very comfortable and effective, especially in more advanced formulations.

Yes, some people can be sensitive or allergic to specific ingredients, particularly preservatives like BAK. Symptoms can include increased eye irritation, redness, or swelling. If you experience these side effects, you should stop using the product and consult a doctor.

You may need to try several different brands and formulations to find what works best for you. It is often recommended to start with a preservative-free lubricating drop and, if symptoms persist, consider a lipid-based or more advanced formula. Your eye doctor can provide a personalized recommendation based on the specific type and severity of your dry eye.