Dilute ethanol versus mechanical debridement before photorefractive keratectomy.

PURPOSE: To compare 18% ethanol versus mechanical epithelial debridement in a group of patients having photorefractive keratectomy (PRK) for low to moderate myopia or astigmatism. SETTING: Hospital San Jose de Monterrey, Mexico. METHODS: This prospective, paired study comprised 18 patients who had bilateral PRK between June 1994 and March 1995. One eye had ethanol (alcohol) debridement and the other, mechanical. Time between PRKs was about 6 months. The two groups (alcohol versus mechanical) were compared for rate of re-epithelialization, refractive outcome, improvement in uncorrected visual acuity (UCVA), subjective haze grading, and loss of best corrected visual acuity (BCVA). RESULTS: There was a nonsignificant trend in the alcohol-treated eyes toward a more rapid visual recovery. One week after PRK, 76% in the alcohol group but only 31% in the mechanical group had a UCVA of 20/40 or better. There were no significant between-group differences in rate of re-epithelialization, refractive outcome, subjective haze grading, and loss of BCVA. CONCLUSION: Chemical de-epithelialization with dilute ethanol appears to be a simple, safe, and effective alternative to mechanical scraping before PRK and might promote faster visual rehabilitation.

Excimer photorefractive keratectomy for low myopia and astigmatism with the Coherent-Schwind Keratom.

PURPOSE: To summarize the initial results of excimer laser photorefractive keratectomy (PRK) in 114 eyes of 89 patients using the Coherent-Schwind system and assess its safety, efficacy, and predictability. SETTING: Hospital San Jose de Monterrey-ITESM, Mexico. METHODS: The Coherent-Schwind Keratom excimer laser was used to correct low myopia (manifest spherical equivalent from -1.00 to -6.00 diopters [D], with manifest cylinder of -1.00 D or less) or myopic astigmatism (manifest spherical equivalent from -2.75 to -6.75 D, with manifest cylinder from -1.00 to -4.50 D) with standard settings. Ablation zone diameters were from 5.9 to 6.3 mm (low myopia) and 5.9 to 8.2 mm (astigmatism) with a repetition rate of 12 Hz. Follow-up was from 1 month (low myopia, n = 71; astigmatism, n = 35) to 6 months (low myopia, n = 36; astigmatism, n = 17). RESULTS: Six months after PRK, uncorrected visual acuity was 20/40 or better in 94% of the low myopia eyes (n = 36) and 77% of the astigmatism eyes (n = 17). Intended correction was within 1.00 D of the target spherical equivalent in 81 and 88% of eyes, respectively. No eyes in the low myopia group lost two lines of best corrected visual acuity, although 12% in the astigmatism group did. CONCLUSION: The Coherent-Schwind excimer laser appears to be effective in the treatment of low myopia and astigmatism, with results comparable to those of other laser systems after 6 months of follow-up. Further study of best corrected visual acuity loss after treatment of compound myopic astigmatism with this laser is warranted.