Three Different Techniques for Photorefractive Keratectomy for Mixed Astigmatism

Abstract

To compare three different PRK techniques for the correction of mixed astigmatism. Sixty eyes of 40 patients affected by mixed astigmatism underwent PRK using an excimer laser with three different techniques: (A) combined myopic spherical and hyperopic cylindrical treatment (mean attempted correction in defocus equivalent [DE], 2 +/- 0.4 D), (B) combined cross-cylinder and spherical equivalent treatment (mean attempted correction in DE, 2.72 +/- 0.6 D), and (C) customized ablation with topography-supported customized ablation (TOSCA) method (mean attempted correction in DE, 2.67 +/- 0.9 D). Twelve months postoperatively, the mean DE in group A was 0.45 +/- 0.6 D and an UCVA of 20/40 or better was achieved in 80% of eyes; the mean DE in group B was 0.55 +/- 0.4 D and an UCVA of 20/40 or better was achieved in 70%; and the mean DE in group C was 0.38 +/- 0.1 D and an UCVA of 20/40 or better was achieved in 90%. No patient lost more than 2 lines of spectacle-corrected visual acuity and there were no complications observed during the follow-up. No statistically significant difference among the three groups was evidenced. PRK for the correction of mixed astigmatism can be considered a useful technique in terms of efficacy, safety, and predictability with all three tested techniques.