Viual performance after photorefractive keratectomy with a 6-mm ablation zone Original Reearch Article

PURPOE: To propectively examine the effect of photorefractive keratectomy with a 6-mm ablation zone on bet-pectacle-corrected viual performance. METHOD: A propective tudy wa conducted of 164 eye of 164 patient with an average (±D) of −4.02 ± 1.74 diopter (range, −0.63 to −8.38 diopter pherical equivalent). Bet-pectacle-corrected high-contrat and low-contrat viual acuity (18% Weber contrat) wa meaured with both natural and dilated pupil. Patient were teted preoperatively and at 3, 6, and 12 month after photorefractive keratectomy. Photorefractive keratectomy wa performed with an argon fluoride excimer laer. Fifty-five eye of 55 patient alo underwent atigmatic keratotomy. REULT: Twelve month after photorefractive keratectomy, bet-pectacle-corrected high-contrat viual acuity with natural pupil howed no ignificant change from preoperative value; mean (±D) change wa 0.004 ± 0.10 logMAR (t = 0.45, P = .65). Bet-pectacle-corrected low-contrat viual acuity with natural pupil wa ignificantly reduced compared to baeline; mean (±D) change wa 0.04 ± 0.13 logMAR (t = 3.3, P = .001). The low-contrat lo wa larger (1.5 line) with dilated pupil; mean (±D) change wa 0.13 ± 0.15 logMAR (t = 9.31, P < .001). Greater loe in dilated low-contrat viual acuity were aociated with concurrent atigmatic keratotomy (t = 2.28, P = .025) and corneal haze of grade 1 or greater (t = 2.71, P = .005). CONCLUION: Reduction in viual performance occur after photorefractive keratectomy with a 6-mm zone. Thee change are greatet for low-contrat viual acuity with dilated pupil. Corneal haze and concurrent atigmatic keratotomy are aociated with greater loe in low-contrat viual acuity. Bet-pectacle-corrected low-contrat viual acuity i a enitive meaure for evaluating viual performance after refractive urgery.