Patients with mixed astigmatism achieve good results after refractive treatment

October 1, 2005

Houston—The CustomVue refractive treatment (VISX/AMO) for patients with mixed astigmatism demonstrated good results at 6 months, according to Douglas D. Koch, MD.

Dr. Koch, professor and the Allen, Mosbacher, and Law Chair in Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, reported that 62% of eyes achieved 20/20 or better uncorrected visual acuity (UCVA) and 96% achieved 20/40 or better UCVA.

Baylor College is one of six centers that participated in the U.S. clinical trials for WaveScan-guided LASIK (VISX/AMO) for hyperopic and mixed astigmatism. In March the FDA approved CustomVue treatment for mixed astigmatism for 1 to 5 D of cylinder.

The study included 86 eyes of 44 patients with mixed astigmatism. The mean age was 41 ± 11 years. Mean sphere was –1.68 ± 1.12 D (range, –0.50 to –3.0 D), and mean cylinder was +2.98 ± 1.20 D (range, 1.25 to 5.0 D). The MRSE was –0.19 ± 0.89 D (range, –0.75 to 1.25 D).

"As we expect with mixed astigmatism, the patients' vision was basically plano in terms of the spherical equivalent," he said.

"Eighty-six percent of these patients saw 20/25, which is extraordinary. Ninety-six percent saw 20/40 or better," he reported.

Dr. Koch noted that the future iris registration feature on the VISX wavefront system, which is currently only available internationally, will help this mixed astigmatism cohort especially.

"For these patients I look forward to being able to use the iris registration because I believe that it will make these results even better," he said.

Accuracy of treatment

The accuracy of the sphere correction was impressive. Seventy-seven percent of patients were within 0.5 D of intended correction, and 56% of the patients with cylinder correction were within 0.5 D. In addition, more than 90% of each were within 1 D. For MRSE, 66% were within 0.5 of intended correction, and 86% were within 1 D.