Comparison of visual results in initial and re-treatment laser in situ keratomileusis procedures for myopia and astigmatism

PURPOSE: To report the results of initial and retreatment laser in situ ker atomileusis procedures for myopia and astigmatism, METHODS: A total of 1161 consecutive inital and retreatment laser in situ k eratomileusis procedures in 697 patients performed between September 19, 19 96, and June 20, 1998, were retrospectively analyzed. Baseline and postoper ative best spectacle-corrected visual acuity, uncorrected visual acuity, sp herical and cylindrical refractions, computerized video keratography, and b iomicroscopy were measured or performed on each eye. RESULTS: Of 1,071 eyes, 900 (84%) underwent a single-laser in situ keratomi leusis procedure, and 171 of 1,071 eyes (16%) underwent one or two re-treat ment procedures. The preoperative mean +/- SD spherical equivalent was -5.0 9 +/- 3.15 diopters (range, -0.75 to -14.38 diopters) and the cylinder was 0.97 +/- 1.09 diopters (range, 0.00 to 3.25 diopters) in the group that und erwent a single laser in situ keratomileusis treatment. The preoperative me an +/- SD spherical equivalent was -6.26 +/- 3.04 diopters (range, -1.75 to -12.88 diopters) and the cylinder was 1.53 +/- 1.11 diopters (range, 0.00 to 3.50 diopters) in the group that underwent re-treatment. Before re-treat ment, 110 eyes (64.3%) in the group that underwent re treatment achieved 20 /40 or better uncorrected visual acuity and 23 eyes (13.5%) achieved 20/25 or better. Three months after re-treatment, 155 eyes (90.6%) achieved 20/40 or better, and 80 eyes (46.8%) achieved 20/25 or better. In the single-pro cedure group, uncorrected visual acuity at 3 months revealed 20/40 vision o r better in 856 eyes (95.1%) and 20/25 vision or better in 572 eyes (63.6%) . Tn this study group, 23.6% of eyes with a preoperative spherical equivale nt greater than -6.0 diopters underwent re-treatment compared with 11.8% of eyes with a preoperative spherical equivalent of -6.0 diopters or less, CONCLUSIONS: Laser in situ keratomileusis appears to be an effective proced ure for mild, moderate, and severe myopia, In eyes with residual refractive error, re-treatment laser in situ keratomileusis procedures can result in good visual outcomes. (C) 2000 by Elsevier Science Inc. All rights reserved .