Excimer laser in situ keratomileusis under a corneal flap for myopia of 2 to 20 diopters

Abstract

Purpose: We studied the efficacy and safety of a recent technique of keratomileusis for myopia, excimer laser in situ keratomileusis.

Methods: We studied retrospectively 88 eyes of 63 patients who received excimer laser in situ keratomileusis with the Chiron Automated Corneal Shaper and the Summit OmniMed laser under a hinged corneal flap without sutures.

Results: Mean follow-up was 5.2 months. Mean spherical equivalent of the manifest refraction before surgery was -8.24 diopters (range, -2.00 to -20.00 diopters). Mean spherical equivalent refraction after surgery was +0.22 +/- 1.42 diopters. Of 40 eyes with a baseline refraction from -2.00 to -6.00 diopters, 25 eyes (63%) had refraction within +/- 0.50 diopter of emmetropia, and 37 eyes (93%) had refraction within +/- 1.00 diopter. In eyes with baseline refraction of -6.12 to -12.00 diopters, postoperative refraction was within +/- 1.00 diopter in 19 (65%) of 29 eyes. In eyes with baseline refraction of -12.10 to -20.00 diopters, postoperative refraction was +/- 1.00 diopter in eight (43%) of 19 eyes. Overall, 64 (72.8%) of 88 eyes had a refraction within +/- 1.00 diopter after surgery. Between three weeks and five months after surgery the change in the mean spherical equivalent refraction was -0.61 diopter in the myopic direction. Uncorrected visual acuity after surgery was 20/20 or better in 31 eyes (36%) and 20/40 or better in 61 eyes (71%). Three eyes (3.6%) lost two lines or more of spectacle-corrected visual acuity, two from progressive myopic maculopathy and one from irregular astigmatism. No eyes had vision-threatening complications.

Conclusion: Excimer laser in situ keratomileusis under a corneal flap can be an effective method of reducing myopia between -2.00 and -20.00 diopters, with minimal complications. Current surgical algorithms need modification to improve predictability of outcome. Stability of refraction after surgery requires further study.