Hydrogel lenses decrease the amount of oxygen reaching the cornea as do most contact lenses. By making the lenses thinner or increasing the water content, or both, more oxygen will reach the cornea. It is not uncommon to have hydrogel lenses made as thin as 0.035 mm.
Lenses are available up to about 75% water content with most lenses being used today range from 38% to 65% water.
