Photorefractive keratectomy with an ablatable mask for myopic astigmatism

PURPOSE: To evaluate efficacy, safety and stability of photoastigmatic keratectomy (PARR) carrried out with a Summit Apex Plus laser using an ablatable mask. METHODS: Forty-one eyes of 41 patients with myopic astigmatism with follow-up of 12 months were evaluated. Treatment efficacy was compared in groups with high (>6.00 D) versus low (less than or equal to 6.00 D) preoperative spherical equivalent subjective manifest refraction, in groups with high (>2.00 D) versus low (less than or equal to 2.00 D) preoperative cylindrical component and in groups divided according to preoperative axis of cylinder. RESULTS: At 12 months after surgery mean spherical equivalent manifest refraction in all 41 eyes was -0.30 +/- 0.90 D. Mean cylinder component was 0.60 +/- 0.70 D. Mean reduction in astigmatic component was 67 +/- 47%. Uncorrected visual acuity of 0.5 or more was achieved in 79% of eyes; 71% of eyes achieved 0.8 or more. At 12 month after surgery, 49% of eyes had a loss of 2 or more lines of spectacle-corrected visual acuity. This loss was restored at 12 months, No statistically significant differences were found between the different subgroups. CONCLUSION: Photoastigmatic keratectomy with ablatable mask gives satisfactory results. No relation in efficacy was found when taking into account the amount of preoperative spherical component, the cylindrical component, or the cylinder axis direction.