Which works better than sodium vitrate or polyvinyl alcohol

Polyvinyl alcohol works better than sodium vitrate. Polyvinyl alcohol can form a film to protect the surface of the eye, preventing external stimuli and pollutants on the eye damage, polyvinyl alcohol is safe and widely used. Sodium vitrate, as an artificial tear ingredient, can cause allergic reactions, has a certain degree of irritation, and long-term use may lead to eye discomfort, dryness and stinging. Therefore, polyvinyl alcohol is better than sodium vitrate.