if prescription is higher than 2,000 degrees which is undoable with the ordinary lens, only have one way to process, it's Biconcave. The shape of this lens is concave on both faces of lens. It is too thinner at the middle of lens, and the vision field of lens is much large. But, your eyes will be looked too small via these lenses while other people see you.

here, prescriptionglassesonline.net could supply this kind of lens