Three different techniques for photorefractive keratectomy for mixed astigmatism.

BACKGROUND AND OBJECTIVE: To compare three different PRK techniques for the correction of mixed astigmatism. PATIENTS AND METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.