What is a scleral or mini-scleral lens?
Mini-scleral lenses are RGP lenses from 14.0 and 18.0 mm in diameter. Unlike corneasclerals, mini-sclerals have a broader contact area with the sclera as the lens becomes larger, although the actual difference between a corneascleral and small mini-scleral of similar diameters is probably moot. Scleral lenses are RGP lenses that are supported entirely by the sclera. They generally range in size from 23 to 25 mm. The lens does not contact the cornea, but traps a layer of fluid between the two surfaces. This makes it ideal for extremely irregular and damaged corneas. These lenses are the most difficult and expensive of all lenses to fit. The complexity ranges from the multi-million dollar manufacturing system of the Boston Foundation for Sight, to the fenestrated two-piece kit version supplied by Gelflex of Australia. Also, a couple of manufacturers exist in Europe, one of which is Innovative Sclerals Ltd. in the UK. Scleral lenses have a long history, and their design precedes the small
