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

Abstract

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.