Excimer laser photoastigmatic refractive keratectomy: eighteen-month follow-up

To study the efficacy of photoastigmatic refractive keratectomy (PARK) by the MEL 60 (Aesculap-Meditec, Jana, Germany) scanning excimer laser for the treatment of myopic astigmatism, with follow-up of 18 months.

One hundred and twenty-eight eyes of 102 patients with different degrees of myopic astigmatism were treated by PARK and followed prospectively in an open study. Ablations were performed with an MEL 60 excimer laser using an astigmatic module.

Mean preoperative refractive cylinder improved from a preoperative 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 group (-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 (85%) at 18 months were within +/-0.5 D of the intended astigmatic correction, with more eyes in the low astigmatic group. One hundred and nineteen eyes (93%) and 114 eyes (97%) at 12 and 18 months, respectively, were within +/-1.0 D of the intended correction. Ninety-two percent to 95.7% of the eyes in the different groups had a postoperative axis less than 10 degrees of the preoperative and intended axis at 12 and 18 months after PARK. Uncorrected visual acuity (UCVA) of 20/40 or better 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.

The data indicate that PARK is an effective surgical tool for correcting astigmatism, especially astigmatism of 1.0 to -2.5 D, with a success rate of approximately 70%.