Healing of alkali burned rabbit corneas with persistent superficial ulceration after excimer laser phototherapeutic keratectomy. Clinical and electron microscopic findings

Purpose: To evaluate epithelial and stromal healing of alkali-burned rabbit corneas with persistent superficial ulceration after

phototherapeutic keratectomy (PTK).

Material and methods: 36 rabbits (36 eyes), with superficial corneal ulcers, which were formed after 10% NaOH corneal burn,

were used. PTK was performed on the 18th day after the burn in 18 rabbits. The base and edges of corneal ulcers in 18 other

rabbits were scraped with scalpel on the 18th day after the burn (control group). Clinical course and electron microscopic changes of post-burn corneal ulcers were investigated after PTK and in the control group.

Results: Clinical course of corneal ulcers has shown that PTK promoted corneal epithelialization and led to formation of less

dense corneal opacities compared to control group. Electron microscopy investigations have shown that PTK 1) activated basal

layer epithelial cells at the corneal ulcer edge; 2) accelerated epithelial basal complex renewal; 3) increased amount of macrophages with cytoplasmic inclusions of necrotic tissues in corneal stroma; 4) increased amount of fibroblasts with activated intracellular organellae in corneal stroma. It led to acceleration of corneal epithelization, cleaning of corneal stroma from necrotic

tissues in the area of corneal ulcer and to more physiologic stromal architecture renewal.

Conclusions: PTK promotes healing of post-burn persistent corneal ulcers in rabbits.