The Mechanism of Action of Sodium Hyaluronate in Eye Drops

Sodium hyaluronate is the sodium salt of hyaluronic acid, possessing excellent water solubility, biocompatibility, and safety. It is widely used in ophthalmic products, especially artificial tears and eye drops for relieving dry eye.

Its core mechanism of action is mainly reflected in the following aspects:

First, its moisturizing and water-locking effect. Sodium hyaluronate molecules contain a large number of hydrophilic groups, which can combine with water molecules to form a stable hydration structure. When instilled into the ocular surface, it can form a water-containing protective film on the cornea and conjunctiva, increasing the water content of the tear film, slowing down water evaporation, and thus improving discomfort symptoms such as dry eyes, foreign body sensation, and stinging.

Second, its viscoelastic protective effect. Sodium hyaluronate has unique viscoelastic properties; it exhibits low viscosity during blinking, reducing friction; and its viscosity increases in a static state, helping to prolong its residence time on the ocular surface. This property reduces friction between the cornea and eyelid during blinking, providing lubrication and cushioning for the corneal epithelium.

Thirdly, it promotes corneal repair. Sodium hyaluronate can bind to receptors on the surface of corneal epithelial cells, participating in cell migration and proliferation, which helps repair damaged corneal epithelium. In cases of mild corneal damage or irritation caused by prolonged contact lens wear, eye drops containing sodium hyaluronate can be used as an adjunct repair product.

Regarding safety, sodium hyaluronate is widely available, usually produced through microbial fermentation, resulting in high purity and low irritation, making it suitable for long-term use. However, the specific frequency of use should still be based on the product instructions or a doctor's advice.

The mechanism of action of sodium hyaluronate in eye drops includes moisturizing and water-locking, lubrication and friction reduction, prolonging residence time, and promoting ocular surface repair, making it one of the important components in current artificial tear formulations.