Scleral lenses are specially designed contact lenses with unique features, such as a larger size and a custom fit to vault over the cornea. The complete vault over the cornea creates a constant reservoir of fluid that sits on top of the cornea and is held in by the lens itself. This layer of fluid not only helps to normalize any corneal irregularities and provide better optical quality but also helps to hydrate the ocular surface. These lenses are oxygen permeable, which makes them healthy for the eye and comfortable for the wearer.