EXCIMER-LASER PHOTOASTIGMATIC REFRACTIVE KERATECTOMY - 18-MONTH FOLLOW-UP

Objective: To study the efficacy of photoastigmatic refractive keratec tomy (PARK) by the MEL 60 (Aesculap-Meditec, Jana, Germany) scanning e xcimer laser for the treatment of myopic astigmatism, with follow-up o f 18 months. Patients and Methods: One hundred and twenty-eight eyes o f 102 patients with different degrees of myopic astigmatism were treat ed by PARK and followed prospectively in an open study. Ablations were performed with an MEL 60 excimer laser using an astigmatic module. Re sults: Mean preoperative refractive cylinder improved from a preoperat ive value of -1.8 +/- 0.8 diopters (D; range, -1.0 to -6.0 D) to -0.3 +/- 0.5 D (range, +1.0 to -2.5 D) at 18 months, The mean reduction in cylindrical correction alone was 84 +/- 37% in the low astigmatism gro up (-1.0 to -1.5 D); 91 +/- 21% in the moderate astigmatism group (-1. 75 to -2.5 D); and 75 +/- 25% in the high astigmatism group (-2.75 to -6.0 D), One hundred and three eyes (80%) at 12 months and 100 eyes (8 5%) at 18 months were within +/-0.5 D of the intended astigmatic corre ction, with more eyes in the low astigmatic group. One hundred and nin eteen eyes (93%) and 114 eyes (97%) at 12 and 18 months, respectively, were within +/-1.0 D of the intended correction. Ninety-two percent t o 95.7% of the eyes in the different groups had a postoperative axis l ess than 10 degrees of the preoperative and intended axis at 12 and 18 months after PARK. Uncorrected visual acuity (UCVA) of 20/40 or bette r was achieved in nearly 84% of the eyes 12 and 18 months after PARK. A UCVA of 20/20 was achieved in 49% of eyes 18 months after PARK. Ten eyes (8%) underwent reoperation at the end of 12 months. Conclusions: The data indicate that PARK is an effective surgical tool for correcti ng astigmatism, especially astigmatism of 1.0 to -2.5 D, with a succes s rate of approximately 70%.