Refractive keratoplasty. Keratophakia in a nonhuman primate.

We performed 11 keratophakia procedures in a baboon (Papio cynocephalus) model using the same instruments and techniques that are presently clinically employed. We requested 10 diopters of correction in nine cases and 14 D in two cases. We were able to achieve a mean (+/- SD) keratometric steepening correction of 5.8 +/- 1.5 D using fresh and 9.3 +/- 5.0 D using prefrozen donor corneas. The overall change was 8.0 +/- 4.3 D. Morphologic results and corneal clarity were consistent with the excellent clinical results. The keratophakia lenticles were sparsely repopulated with keratocytes up to six months following surgery, but at 12 months, partial keratocyte repopulation of one lenticle did occur. We recommend that the baboon model be used for evaluation of all lamellar refractive surgical procedures.