Epikeratophakia: existing limitations and future modifications

The predictability of optical correction has been a problem for all forms of refractive corneal surgery in epikeratophakia, changes in graft dimensions and surgical technique improved accuracy, but several problems still exist in cryolathing preserved corneal tissue. Preserved corneal tissue is quite oedematous and when frozen on the cryolathe, assumes an irregular shape. A mechanical technique to dehydrate tissue was developed which yields corneal tissue which behaves in a predictable fashion. The use of donor corneal tissue in refractive surgery has certain inherent limitations. There is no way of measuring the power of the lathed corneal lens prior to surgery; the power is a function of the shape the lens will take in vivo. The ability to supply large numbers of donor corneal buttons may be an impractical task should this type of surgery become widely used. The use of alloplastic lenses should overcome most of these difficulties.