Endothelial cell loss following radial keratotomy in a primate model.

The effect of radial keratotomy on the corneal endothelium of subhuman primates was studied by serial specular microscopy and histopathology. Fixed-frame analysis of specular micrographs of 13 operated eyes at one month after surgery revealed an endothelial cell loss of 13% (+/- 4%). Follow-up of all 13 eyes for six months disclosed no statistically significant progressive endothelial cell loss. Similarly, no significant loss could be demonstrated in five eyes followed up for 18 months and two eyes followed up four years after surgery. Variable frame analyses of specular micrographs of all 13 unoperated eyes followed up for six months also did not suggest progressive endothelial cell loss following radial keratotomy. Histopathology and ultrastructural studies of corneas undergoing radial keratotomy disclosed no abnormalities suggesting ongoing endothelial cell damage. These findings suggest that radial keratotomy produces an acute postoperative endothelial cell loss that is nonprogressive. Much longer term follow-up with larger numbers of subjects is necessary before the ultimate delayed effects of radial keratotomy on the endothelium can be determined.