The hyaluronic acid is a mucopolysaccharide present in the eyes and other parts of the body. Thanks to its special characteristics can join to several molecules of water present in the tear.
The molecules of hyaluronic acid differ in function of the length of the associated chain. Long chain molecules or high molecular weight, retain more molecules of water. At the same concentration of hyaluronic acid, the one with the highest molecular weight is the one that contributes the most viscosity. In addition, it has a greater hydration capacity and a longer residence time on the ocular surface.