Alterations in corneal morphology following thermokeratoplasty

Fifteen corneal buttons were removed at keratoplasty from patients with keratoconus who had previously undergone thermokeratoplasty (TKP). The buttons were studied with light microscopy, in an attempt to analyze the type of changes produced by TKP. The principal histologic findings in patients with retarded epithelial healing (8 of 15) included epithelial thinning, bullous keratopathy, thickening of the epithelial basement membrane, and frequent destruction of Bowman's membrane. More severely affected patients showed asceptic stromal necrosis and fibrinous iritis with hypopyon. A poor visual result in patients with normal epithelial healing (7 of 15) was caused by superficial stromal scarring or persistent inflammatory infiltrate. Vascularization was seen in only one patient.