PROSTAGLANDIN-E(2) PRODUCTION AFTER LAMELLAR KERATECTOMY AND PHOTOREFRACTIVE KERATECTOMY

PURPOSE: To compare the levels of prostaglandin E2 (PGE2) in corneal t issue after 193-nanometer excimer laser keratectomy and mechanical ker atectomy with a microkeratome. METHODS: Four rabbits underwent 193-nan ometer excimer laser phototherapeutic keratectomy on one eye, and lame llar keratectomy with the micro-keratome on the fellow eye. The cornea s were harvested at 10 hours after the treatment and quantitated for P GE2 levels using an enzyme-linked immune assay. Control levels of PGE2 in untreated corneas were obtained from a previous study. RESULTS: Un operated control corneas had low levels of PGE2 (1.79 +/- 1.0 pg/mL). Both surgical techniques resulted in a significant (p < .01) increase in PGE2. Corneas ablated mechanically with the microkeratome had an av erage PGE2 level of 15.48 +/- 5.36 pg/mL, which represented an 8.6-fol d increase compared to control; there was an additional 330% mean incr ease in PGE 2 concentration in the laser-ablated corneas (51.29 +/- 36 .08 pg/mL) compared to the corneas treated with mechanical lamellar ke ratectomy (p = .014). CONCLUSIONS: Mechanical and photochemical superf icial keratectomies induce production of an inflammatory mediator, PGE 2. The 193-nanometer excimer laser irradiation causes a greater increa se of PGE, production in the corneal tissue than does keratectomy with the microkeratome; this observation may support a role for cyclo-oxyg enase inhibitors in postoperative therapy.