Prophylactic mitomycin C to inhibit corneal haze after photorefractive keratectomy for residual myopia following radial keratotomy

PURPOSE: To evaluate the efficacy and safety of mitomycin C (MMC) 0.02% in inhibiting haze formation after excimer laser photorefractive keratectomy (PRK) for residual myopia following radial keratotomy (RK). METHODS: A prospective, nonrandomized, noncomparative interventional case series was conducted of 22 eyes (14 patients) with residual myopia after RK performed at a single institution. All eyes were treated with PRK and a single intraoperative topical application of MMC 0.02% solution for 2 minutes using a soaked cellulose sponge placed over the ablated area. Refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and slit-lamp evidence of cotneal opacity (haze) were evaluated over 12 months. RESULTS: Twelve months postoperatively, 3 eyes showed grade 1 haze, and 2 eyes showed grade 0.5 haze. Twelve months postoperatively, 2 (9%) eyes had UCVA > or = 20/20. No eye before and 17 (77%) eyes after treatment had UCVA > or = 20/40, and no eye before and 9 eyes (40.9%) after treatment had UCVA > or = 20/25. Best spectacle-corrected visual acuity was > or = 20/40 in all (100%) eyes and 21 (95%) eyes before and after treatment, respectively, and > or = 20/25 in 12 (54.5%) eyes before and after treatment. One (4.5%) eye lost 1 line of BSCVA. Mean spherical equivalent refraction achieved was -0.18 diopters (D) (range: -0.75 to +0.50 D) compared to -2.72 D (range: -1.50 to -4.00 D) before treatment. Twelve months after treatment, 19 (85.5%) eyes had a refractive outcome within +/- 0.50 D. CONCLUSIONS: A single intraoperative application of MMC 0.02% for 2 minutes appears to be effective in preventing subepithelial haze after PRK for residual myopia in patients with undercorrection or regression following RK.