Early Results of Photorefractive Keratectomy for Myopic Astigmatism

BACKGROUND: The Technolas Keracor 116 excimer laser has been used to correct myopic astigmatism. The purpose of this study was to evaluate the early results in our patients. METHODS: The Technolas Keracor 116 excimer utilizes a scanning beam to correct myopic astigmatism. Following the correction of the astigmatic error, spherical myopic component is then treated. Twenty-eight eyes with myopic astigmatism were treated utilizing a 4 x 12 mm ablation zone for astigmatism and 4.5 mm to 6.6 mm transition zone for the spherical component at the same session. The mean preoperative spherical equivalent refraction was -4.87 +/- 3.48 diopters (D) (range: -1.00 to -14.25) and the mean preoperative astigmatic error was -2.53 +/- 1.49 D (range: -1.00 to -6.00 D) All eyes received dexamethasone eye drops for 3 months. RESULTS: At 6 months, the mean spherical equivalent refraction was +0.23 D (range +1.38 to -1.50 D), the mean postoperative refractive cylinder was -0.16 +/- 0.99 D (range: +1.50 to -2.00 D) and 78% of the eyes had a refraction within +/- 1 D. Fifty-five percent achieved 20/40 or better uncorrected visual acuity. In three cases there was one line loss and in two cases there was two line loss in best corrected spectacle visual acuity. CONCLUSIONS: Early results from this study suggest that excimer laser photorefractive keratectomy effectively reduces myopic astigmatism. The treatment of astigmatism offers a new challenge for excimer laser corneal surgery. Lasers utilize different methods to control the beam that reshapes the cornea.