One-year evaluation of myopic laser photoastigmatic refractive keratectomy using the summit apex plus: phase III of a Food and Drug Administration clinical trial

PURPOSE: To prospectively evaluate the safety and efficacy of the Summit Apex Plus excimer laser in the treatment of primary compound myopic astigmatism. DESIGN: Prospective noncomparative interventional case series. PARTICIPANTS: Patients with primary compound myopic astigmatism: sphere of -1.0 to -7.0 diopters (D) and cylinder -1.0 to -5.0 D. METHODS: Ninety-three eyes of 56 patients with a mean spherical equivalent of -4.98 +/- 1.80 D (-1.75 to -8.5) underwent photoastigmatic refractive keratectomy (PARK) with the Summit Apex Plus excimer laser using erodible mask technology. Prospective follow-up is analyzed at 1-year postoperatively. MAIN OUTCOME MEASURES: Postoperative reduction in myopic sphere, myopic astigmatism, spherical equivalent, angle of error, magnitude of error, difference vector, uncorrected visual acuity, and corneal haze. RESULTS: Seventy-one eyes were available at 1-year follow-up. Mean spherical equivalent was reduced 86.5% to a mean residual of -0. 65 D +/-0.70 D (-2.88-+1.13 D). Astigmatism was reduced 66.2% to a mean residual of -0.76 +/- 0.52 D (-2.25-0.00 D); 77.5% were within 1.0 D of attempted correction; 1.4% of eyes experienced an overcorrection >1.0 D of spherical equivalent; 0.27 D of mean myopic regression was demonstrated between 1 and 12 months; 93.0% of eyes achieved an uncorrected visual acuity of 20/40 or better; and 49.3% of eyes achieved an uncorrected visual acuity of 20/20 or better. CONCLUSIONS: PARK with the Summit Apex Plus excimer laser is effective at reducing compound myopic astigmatism. However, current laser algorithms result in consistent undercorrection of both the compound myopia and the astigmatic component.