John S M Chang1, Antony K P Law2, Jack C M Ng1, Vincent K C Chan1. 1. From the Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong Special Administration Region, China. 2. From the Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong Special Administration Region, China. Electronic address: pantonylkp@gmail.com.
Abstract
PURPOSE: To compare the refractive and visual outcomes between 2 ablation centration points, 80% and 100% from the pupil center toward the coaxially sighted corneal light reflex. SETTING: Hong Kong Sanatorium and Hospital, Hong Kong, China. DESIGN: Retrospective comparative study. METHODS: All eyes had myopic laser in situ keratomileusis with the ablation 80% or 100% from the pupil center toward the coaxially sighted corneal light reflex. Three months postoperatively, the refractive and visual outcomes were compared between groups. Subgroup analysis was also performed for the large-angle κ and small-angle κ groups. RESULTS: There were no differences in the preoperative variables between groups. Three months postoperatively, the sphere was significantly more hyperopic in the 80% group than in the 100% group (0.19 diopter [D] versus 0.09 D) (P = .009) and the cylinder was significantly lower in the 80% group (0.25 D versus 0.33 D) (P = .011). More eyes achieved zero astigmatism in the 80% group than in the 100% group (43.9% versus 34.2%), and fewer eyes had astigmatism greater than 0.75 D in the 80% group (0.9% versus 6.1%) (P = .039). The error from the target refraction indicated that the 80% group tended to have significantly less undercorrection (P = .045). There were no significant differences in the other outcomes. Subgroup analysis did not show significant findings for the large-angle κ. CONCLUSIONS: Both 80% centration and 100% centration were safe and effective. Compared with the 100% group, the 80% group had less astigmatism and less undercorrection.
PURPOSE: To compare the refractive and visual outcomes between 2 ablation centration points, 80% and 100% from the pupil center toward the coaxially sighted corneal light reflex. SETTING: Hong Kong Sanatorium and Hospital, Hong Kong, China. DESIGN: Retrospective comparative study. METHODS: All eyes had myopic laser in situ keratomileusis with the ablation 80% or 100% from the pupil center toward the coaxially sighted corneal light reflex. Three months postoperatively, the refractive and visual outcomes were compared between groups. Subgroup analysis was also performed for the large-angle κ and small-angle κ groups. RESULTS: There were no differences in the preoperative variables between groups. Three months postoperatively, the sphere was significantly more hyperopic in the 80% group than in the 100% group (0.19 diopter [D] versus 0.09 D) (P = .009) and the cylinder was significantly lower in the 80% group (0.25 D versus 0.33 D) (P = .011). More eyes achieved zero astigmatism in the 80% group than in the 100% group (43.9% versus 34.2%), and fewer eyes had astigmatism greater than 0.75 D in the 80% group (0.9% versus 6.1%) (P = .039). The error from the target refraction indicated that the 80% group tended to have significantly less undercorrection (P = .045). There were no significant differences in the other outcomes. Subgroup analysis did not show significant findings for the large-angle κ. CONCLUSIONS: Both 80% centration and 100% centration were safe and effective. Compared with the 100% group, the 80% group had less astigmatism and less undercorrection.