Mechanism of Action of Hyaluronic Acid in Ophthalmic Lubricating Solutions

The eye is one of the most sensitive and easily dried-out organs in the human body, especially in air-conditioned rooms, during prolonged periods of eye use, or for those suffering from dry eye syndrome. Insufficient lubrication of the ocular surface can easily cause irritation, fatigue, and even corneal damage. Hyaluronic acid is widely used in ophthalmic lubricating solutions (commonly known as artificial tears). Its unique moisturizing and biocompatible properties make it an important component for relieving dry eye syndrome and protecting the ocular surface.

Hyaluronic acid is a natural polysaccharide with extremely strong hydrophilicity, capable of absorbing hundreds of times its own weight in water. When dissolved in ophthalmic lubricating solutions, it forms a high-viscosity hydrogel layer that can form a protective film on the corneal and conjunctival surfaces. This film not only reduces the evaporation of moisture from the ocular surface but also buffers the mechanical pressure on the eye during blinking or external stimuli, reducing the occurrence of micro-damage to the ocular surface.

From a molecular perspective, hyaluronic acid functions through three main mechanisms: First, its high molecular weight structure gives it a significant water-absorbing capacity, stabilizing corneal surface moisture and maintaining tear film thickness. Second, hyaluronic acid binds to receptors on the surface of corneal epithelial cells (such as CD44 receptors), promoting epithelial cell repair and adhesion, thereby enhancing corneal barrier function. Finally, hyaluronic acid can also slowly release water through its viscoelastic properties, prolonging the duration of lubrication and improving the comfort of artificial tears.

Furthermore, the molecular weight of hyaluronic acid affects its performance on the ocular surface: high molecular weight hyaluronic acid has higher viscosity and a longer residence time; low molecular weight hyaluronic acid penetrates more easily, promoting cell repair. Modern ophthalmic lubricants typically select single or mixed molecular weight hyaluronic acid to balance lubrication and repair.

Hyaluronic acid in ophthalmic lubricants not only hydrates and moisturizes but also protects the cornea, relieves dry eye symptoms, and promotes repair through interaction with corneal cells. This makes it an indispensable, safe, and effective ingredient in modern ophthalmic care.