Photorefractive Keratectomy Following Radial Keratotomy

BACKGROUND: Excimer laser photorefractive keratectomy (PRK) has been used to correct residual myopia in eyes that have had refractive keratotomy. METHODS: Nine eyes of eight patients were studied at a mean of 13 months after PRK. Previous procedures included radial keratotomy (9 eyes) and myopic keratomileusis (1 eye). PRK was performed using a Summit Technology excimer laser with a 5.0-mm diameter ablation zone. RESULTS: Uncorrected visual acuity improved in 7 of 9 eyes. The refractive outcome was within 1.00 diopter (D) of attempted correction for 3 of 9 eyes. Spectacle-corrected visual acuity decreased 2 or more Snellen lines in 2 of 9 eyes. Subepithelial corneal stromal haze was seen 1 month postoperatively in 6 of 8 eyes and was present in 4 of 6 eyes at 1 year. Stromal haze was associated with regression of the refractive effect of the PRK. CONCLUSIONS: PRK in eyes with previous radial keratotomy appears to be less predictable and may be associated with greater corneal haze and regression of refractive correction than in previously unoperated eyes. Activation of stromal fibroblasts in the previous corneal incisions may cause these findings.