Artificial tears: the main types of ingredients used in various formulations in the treatment of dry eye disease

doi:10.15406/AOVS.2025.15.00477

Advances in

eISSN: 2377-4290

Ophthalmology & Visual System

Mini Review Volume 15 Issue 1

Artificial tears: the main types of ingredients used in various formulations in the treatment of dry eye disease

Gkokgos Emmanouil

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Ophthalmologist Surgeon, Antigonis 4 –Thiva, Greece

Correspondence: Gkokgos Emmanouil, MD, Ophthalmologist Surgeon, Antigonis 4 –Thiva, ZIP Code: 32200, Greece, Tel +2262027277

Received: February 19, 2025 | Published: March 25, 2025

Citation: Emmanouil G. Artificial tears: the main types of ingredients used in various formulations in the treatment of dry eye disease. Adv Ophthalmol Vis Syst. 2025;15(1):13-14. DOI: 10.15406/AOVS.2025.15.00477

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Abstract

Dry eye syndrome is a multifactorial ocular surface disease characterized by tear film instability, hyperosmolarity, and inflammation. Substituted tears play a pivotal role in managing this condition, with numerous formulations available to address different aspects of tear film deficiency. This article reviews the ingredients of substituted tear formulations and their underlying mechanisms.

Keywords: dry eye syndrome, artificial tears, osmoprotectants, electrolytes

Introduction

Dry eye syndrome (DES) affects millions worldwide, significantly impairing quality of life through symptoms such as ocular discomfort, burning, and visual fluctuations. The etiology of DES is complex and may involve aqueous tear deficiency, evaporative loss, or most often a combination of both. As the first-line treatment for DES, substituted tears are designed to mimic natural tears and restore ocular surface homeostasis. However, given the diversity of formulations—including aqueous solutions, gels, and emulsions—selecting the most appropriate product remains a challenge for clinicians.¹

This article, inspired by Sinjab Academy, aims to give a short and accurate evidence on the ingredients the artificial tears (ATs) are composed, in order to differentiate the various formulations for optimal strategies and treatment for dry eye disease.

The main types of ingredients used in different formulations are viscosity- enhancing agents, electrolytes, osmo-protectants, oily agents and surfactants, antioxidants and agents promoting wound healing

Viscosity enhancing agents

Viscosity-enhancing agents represent the most frequently used ingredients, composing the bulk of ATs. They belong to one these categories: cellulose derivatives, hyaluronic acid, dextran, glycol, HP guar, polyvinyl alcohol and povidone.² They act as water retaining agents and have been proved to be beneficial for patients with DED by increasing tear film thickness and retention of ATs at the ocular surface.

Electrolytes

Electrolytes are naturally present on tear film and they maintain the osmotic balance of the ocular surface. These are sodium, potassium, chloride, magnesium, calcium and boric acid. They are essential as regulators of the osmolarity of the ATs and stabilisation of the PH on certain formulations.³ The play an important role in counterbalancing the hyperosmolarity of the tear film induced by DED.^4,5

Osmoprotectans

Hyperosmolarity of the tear film is a hallmark of DES. Osmoprotectants maintain the osmotic balance of the ocular surface. Formulations incorporating osmoprotectants help normalize tear film osmolarity, reduce epithelial cell stress, and reduce inflammation.

These are L-carnitine, erythritol, betaine, sorbitol, glycerin, trehalose and taurine. They protect epithelial cells from hyperosmolar stress and they prevent apoptosis of the cornel and conjunctival cells. Osmoprotectants also reduce matrix metalloproteinase (MMP) synthesis and oxidative stress and can regulate the autophagic process.^6,7

Oily agents and surfactants

They replace the deficient lipid layer, they reduce evaporation, they smooth the optical surface of the cornea and help to maintain a good quality of vision.⁸ They are available mostly as liposomes or emulsions.^9,10 There are mineral oils (NP), triglycerides (NP), castor oil (NP), cetaklkonium chloride (P) and phosphatidylglycerol (P).

Antioxidants

Inflammation associated with DED is correlated with oxidative stress and tissue damage. Antioxidants prevent ocular surface cell apoptosis caused by oxidative stress even though more clinical studies need to be performed to prove their efficacy on DED signs. They include Vitamin A, E, B6, B12, Co-enzyme q10 and lipoid acid. Topical and systemic vitamin supplementation has been used in Japanese formulations in OSD.

Agents promoting wound healing

These are high molecular weight hyaluronic acid (HMW-HA) and Carmellose Sodium. HMW-HA can bind to C44 receptor present on most cell types including human cornea epithelial cells¹¹ and accelerates wound healing after corneal debridement abrasion. Carmellose sodium also binds to human cornea epithelial cells and promotes re-epithelization.¹²

Discussion

Recent advances in the formulation of substituted tears reflect a nuanced understanding of dry eye pathophysiology. While traditional aqueous-based drops remain effective for many, the integration of agents that target osmolarity and lipid deficiency has expanded the therapeutic arsenal. Importantly, randomized controlled trials have begun to elucidate the differential benefits of these formulations, suggesting that a “one size fits all” approach is suboptimal.

Artificial tears (ATs) are the cornerstone in the management of dry eye syndrome. Despite the large variety of ATs available on the market, patient satisfaction remains very low.¹³ Understanding the roles of ingredients contained in ATs is essential to provide each patient with the most appropriate formulations. Contrary to medicated eye drops, ATs are usually designated as “medical devices” and under these designations they have a lower level of clinical evidence to obtain marketing authorization. The selection of appropriate formulation should be guided by the properties of the ingredients the formulation is composed.

Conclusion

Understanding the properties and the ingredients of each formulation of ATs that exist on the market is essential for clinicians. We all have to remain abreast of emerging data, as the field continues to evolve with the introduction of novel polymers and combination therapies. Future research should focus on head-to-head comparisons and long-term outcomes to further refine treatment algorithms.