Photoastigmatic refractive keratectomy for primary treatment and revision of myopic astigmatism

Purpose: To evaluate the results in 43 eyes treated with a rotating mask for myopic astigmatism and followed for up to 1 year. Setting: Lucerne Eye Clinic, Cantonal Hospital, Lucerne, Switzerland. Methods: Thirty-two patients (42 eyes) were selected to have photoastigmatic refractive keratectomy (PARK). In 33% (14 eyes), this treatment was the second or third ablation. The Aesculap Meditec MEL 60 excimer laser was operated in the scanning slit mode, and a rotating mask was used. To evaluate cylindrical shaping, vector analysis was performed. Results: One year after PARK, mean uncorrected visual acuity in all patients (26 eyes) improved from 20/160 preoperatively to 20/40. Surgically induced astigmatism in 20 of 26 eyes (77%) was within +/-1.00 diopter (D) of the targeted induced astigmatism. At 1 year, 81% of patients who had primary excimer laser treatment for myopic astigmatism equivalent to -10.00 D or less were within +/-1.00 D of target refraction compared with 44% of re-treated eyes. Conclusion: The result of PARK in eyes with low to moderate degrees of myopic astigmatism was satisfactory. However, in eyes with extensive scarring and wound healing activity after the first ablation, re-treatment was less predictable.