Effects of freezing on the corneal stroma of the rabbit after keratophakia.

In three rabbits a keratophakia as described by Barraquer (1972) was performed on both eyes, in one rabbit it was performed on one eye. In the right eye no cryoprotective agent was used, in the left eye the cryoprotective agent KM 26 was applied. Twelve hours after the operation, the majority of keratocytes in the tissue lens were destroyed. The nuclear chromatin was clumped, the cell membrane was destroyed and cytoplasm showed vacuolar alteration; cell organelles were no longer recognizable. After 24 h hardly any keratocytes were found. All corneae operated on with and without a cryoprotective agent, showed the same morphology. The cell debris was removed by macrophages, which could be found earlier in corneae operated on without cryoprotection. Three weeks after keratophakia no increase in the number of the residual keratocytes had occurred.