Tae-im Kim1, Seung-jae Yang, Hungwon Tchah. 1. Department of Ophthalmology, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
Abstract
PURPOSE: One aim of corneal refractive surgery is to correct defocus and astigmatism. In the process of correcting lower order aberrations, higher order ocular aberrations increase. To evaluate the effectiveness of wavefront-guided laser in situ keratomileusis (LASIK) in reducing the increase of higher order aberration, we compared aberrational change after LASIK with conventional and wavefront-guided customized ablation. METHODS: Our study included 48 eyes of 24 patients. We performed conventional LASIK in one eye (Group 1) and wavefront-guided customized ablation in the other eye (Group 2). Ocular aberration was measured with the Zywave, a type of Shack-Hartmann aberrometer. We then compared low and high order aberrations, contrast sensitivity, visual acuity, corneal topography, and manifest refraction preoperatively and postoperatively at 1 and 3 months. RESULTS: Uncorrected visual acuity improved to more than 20/20 in two eyes in the conventional ablation group and in five eyes in the customized ablation group. In the conventional ablation group, Root-mean-square for higher order (RMS(H)) was 0.215 preoperatively, 0.465 (216.3%) at 1 month, and 0.418 (194.4%) at 3 months. In the customized ablation group, RMS(H) was 0.207 preoperatively, 0.380 (183.6%) at 1 month, and 0.371 (179.2%) at 3 months after LASIK. Mesopic contrast sensitivity in the customized ablation group was higher than that in the conventional ablation group, but this change was not statistically significant. CONCLUSIONS: Wavefront-guided customized ablation reduced the increase of high order aberrations resulting from LASIK. In terms of visual acuity, patient preference, and mesopic contrast sensitivity, wavefront-guided customized ablation produced slightly-but not statistically significant-better results.
PURPOSE: One aim of corneal refractive surgery is to correct defocus and astigmatism. In the process of correcting lower order aberrations, higher order ocular aberrations increase. To evaluate the effectiveness of wavefront-guided laser in situ keratomileusis (LASIK) in reducing the increase of higher order aberration, we compared aberrational change after LASIK with conventional and wavefront-guided customized ablation. METHODS: Our study included 48 eyes of 24 patients. We performed conventional LASIK in one eye (Group 1) and wavefront-guided customized ablation in the other eye (Group 2). Ocular aberration was measured with the Zywave, a type of Shack-Hartmann aberrometer. We then compared low and high order aberrations, contrast sensitivity, visual acuity, corneal topography, and manifest refraction preoperatively and postoperatively at 1 and 3 months. RESULTS: Uncorrected visual acuity improved to more than 20/20 in two eyes in the conventional ablation group and in five eyes in the customized ablation group. In the conventional ablation group, Root-mean-square for higher order (RMS(H)) was 0.215 preoperatively, 0.465 (216.3%) at 1 month, and 0.418 (194.4%) at 3 months. In the customized ablation group, RMS(H) was 0.207 preoperatively, 0.380 (183.6%) at 1 month, and 0.371 (179.2%) at 3 months after LASIK. Mesopic contrast sensitivity in the customized ablation group was higher than that in the conventional ablation group, but this change was not statistically significant. CONCLUSIONS: Wavefront-guided customized ablation reduced the increase of high order aberrations resulting from LASIK. In terms of visual acuity, patient preference, and mesopic contrast sensitivity, wavefront-guided customized ablation produced slightly-but not statistically significant-better results.