Corneal rupture following radial keratotomy in cats subjected to BB gun injury.

We performed this investigation to determine if radial keratotomy (RK) predisposes an eye to rupture when exposed to projectile trauma. Radial keratotomy was performed on 22 cat eyes; 17 eyes were used as controls. Incision depth was set at 90% by averaging ten corneal thickness readings by ultrasonic pachymetry of each cornea. An optical zone of 4.0 mm was used and eight incisions were made. Eight weeks after RK the cats were divided into three groups, subjected respectively to BB velocities of 148.5 ft/sec (N = 4), 190 ft/sec (N = 5), and 240 ft/sec (N = 13). In groups 1 and 2, all nine eyes had hyphemas and no eyes perforated. In group 3, four of 13 RK eyes had corneal rupture. All control eyes had hyphemas and none ruptured. The study suggests that RK can predispose to rupture eyes exposed to projectile trauma sufficient to produce hyphema.