CMC vs. Sodium Hyaluronate
Carboxymethylcellulose (CMC) and Sodium Hyaluronate (SH) are among the most widely used active agents in artificial tears. Both work by staying on the eye surface longer than plain water, reducing evaporation and improving comfort — but they behave slightly differently.
CMC is a viscosity-modifying polymer that forms a protective film over the corneal surface. It spreads well, feels comfortable on instillation, and is an excellent choice for mild to moderate dry eye and everyday use. Dual formulations such as Aquasight combine CMC 0.5% with Glycerine 0.5% for added moisture retention.
Sodium Hyaluronate is a naturally occurring molecule known for its impressive water-binding capacity — one gram can hold up to a litre of water. It provides longer-lasting relief and excellent surface protection, making it well suited to moderate to severe dry eye. Hylusight delivers SH 0.1%, while Hylusight 1.4% offers a higher concentration for demanding cases.
For intermittent, screen-related dryness, a CMC-based drop used as needed is often sufficient. When symptoms are more persistent, frequent, or associated with corneal surface damage, a sodium hyaluronate formulation may provide longer relief. Many patients find it useful to keep both types and match the drop to the day.
If you use lubricating drops more than four times daily, prefer preservative-free unit-dose or multi-dose bottles to avoid preservative-related irritation. Products like Opfresh and Op-Hydro Gel are designed with gentle use in mind.
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