Naoyuki Maeda1, Tomoya Nakagawa1, Ryo Kosaki1, Shizuka Koh1, Makoto Saika2, Takashi Fujikado3, Kohji Nishida1. 1. Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan. 2. Research Institute, Optics Laboratory, Topcon Corporation, Tokyo, Japan. 3. Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan.
Abstract
PURPOSE: We investigated higher-order aberrations (HOAs) of the anterior and posterior corneal surfaces in patients with keratectasia after LASIK. METHODS: The subjects comprised four groups: 12 eyes with keratectasia after LASIK, 30 eyes following LASIK without keratectasia, 30 keratoconic eyes, and 30 normal eyes. Corneal HOAs due to the anterior and posterior corneal surfaces for 6-mm pupils (root mean square [μm]) were obtained using a Scheimpflug-based corneal tomographer and compared among the four groups. RESULTS: There were significant differences in total HOAs of the anterior and posterior corneal surfaces (mean ± SD) in the keratectasia (2.49 ± 1.37 and 0.83 ± 0.57), keratoconus (4.50 ± 2.57 and 1.18 ± 0.65), LASIK (0.84 ± 0.25 and 0.14 ± 0.04), and normal (0.52 ± 0.15 and 0.17 ± 0.06) groups except for between keratoconus and keratectasia at the posterior surface. Keratectasia and keratoconus showed similar coma-dominant patterns at both surfaces, and there were no significant differences in the Zernike terms between both groups except for the total HOAs and coma aberration at the anterior surface. CONCLUSIONS: Although flap creation and laser ablation were supposed to center on the primary line of sight in LASIK, keratectasia after LASIK showed coma-dominant HOAs at both corneal surfaces. This suggests that the cornea in keratectasia has optical properties similar to those in keratoconus. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.
PURPOSE: We investigated higher-order aberrations (HOAs) of the anterior and posterior corneal surfaces in patients with keratectasia after LASIK. METHODS: The subjects comprised four groups: 12 eyes with keratectasia after LASIK, 30 eyes following LASIK without keratectasia, 30 keratoconic eyes, and 30 normal eyes. Corneal HOAs due to the anterior and posterior corneal surfaces for 6-mm pupils (root mean square [μm]) were obtained using a Scheimpflug-based corneal tomographer and compared among the four groups. RESULTS: There were significant differences in total HOAs of the anterior and posterior corneal surfaces (mean ± SD) in the keratectasia (2.49 ± 1.37 and 0.83 ± 0.57), keratoconus (4.50 ± 2.57 and 1.18 ± 0.65), LASIK (0.84 ± 0.25 and 0.14 ± 0.04), and normal (0.52 ± 0.15 and 0.17 ± 0.06) groups except for between keratoconus and keratectasia at the posterior surface. Keratectasia and keratoconus showed similar coma-dominant patterns at both surfaces, and there were no significant differences in the Zernike terms between both groups except for the total HOAs and coma aberration at the anterior surface. CONCLUSIONS: Although flap creation and laser ablation were supposed to center on the primary line of sight in LASIK, keratectasia after LASIK showed coma-dominant HOAs at both corneal surfaces. This suggests that the cornea in keratectasia has optical properties similar to those in keratoconus. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.