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 kakali-bumed 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.

Treatment of post-burn persistent corneal ulcers with excimer laser phototherapeutic keratectomy. Prospective clinical trial.

PURPOSE: To evaluate efficacy of excimer laser phototherapeutic keratectomy (PTK) i n treatment of patients with post-burn persistent corneal ulcers. MATERIAL AND METHODS: Study design--nonrandomized trial with a "historic" control group. 54 eyes (53 patient) with central superficial post-burn corneal ulcers that were formed in different time frame (18-104 days) after grade IV burns were included into the study. Among these 26 patients (26 eyes) were included prospectively--they underwent 1-time PTK. Control group consists of 27 patients (28 eyes), who underwent surgical keratectomy of ulcer edge and base. Indication for surgery in both groups was non-decreasing size of ulcer during 7-14 days of conventional treatment. Patients of both groups wore therapeutic contact lenses after surgery. Outcome measures were number of cases of corneal healing, number of complications, terms of corneal epithelialization, visual acuity. RESULTS: PTK promoted corneal healing in 24/26 patients, surgical keratectomy was effective in 27/28 patients. PTK (1) did not lead to complications (one corneal perforation in control group), (2) accelerated corneal epithelialization on 18.4 days compared to surgical keratectomy group (p = 0.000, Kruskal-Wallis test) (3) improved mean visual acuity on 0.08 compared to control group in 6 months follow-up examination (Bonferroni corrected p = 0.002, Kruskal-Wallis test). CONCLUSION: PTK is a safe and effective method for treatment of post-burn superficial persistent corneal ulcers recalcitrant to conventional therapy.