Laboratory evaluation of freeze vs nonfreeze lamellar refractive keratoplasty

Four pairs of human eyes were operated on to correct 10 diopters of myopia. One eye underwent standard myopic keratomileusis, and the mate underwent planar lamellar refractive keratoplasty (PLRK). Cryolathing produced morphologic alterations in all layers. Planar lamellar refractive keratoplasty produced a smoother stromal surface in the optic zone. Peripheral triangular surface depressions in the lenticule, corresponding to fixation facets on the PLRK unit, were the only morphologic alterations noted. It appears that PLRK eliminates many adverse features associated with tissue freezing and lyophilization.