| Topography-guided Treatment of Decentered Laser ablation Using LaserSight’s Excimer Laser
Liangcheng Wu, MD1; Xingtao Zhou, MD2; Zhaohu Ouyang, MD1; Chenghai, Weng, MD1; Renyuan Chu, MD2
Abstract
Purpose: To assess the efficacy of LaserSight’s topography-guided excimer laser system for correction of previous decentered laser ablation.
Methods: Eighteen eyes (18 patients who underwent both eyes myopic LASIK before) were retreated using LaserSight’s excimer laser because of symptomatic decentration. The 18 eyes formed experimental group, and the control group consisted of another asymptomatic eyes with or without mild decentration in the 18 patients. Changes in ablation center, best spectacle-corrected visual acuity (BSCVA), contrast sensitivity and cornea aberrations after retreatment were analyzed and compared to control.
Results: The average decentration was reduced significantly from 1.32±0.28mm (range 0.82 to 1.9mm) to 0.61±0.23mm (range 0.25 to 1.06mm) after retreatment (P=0.000). Mean BSCVA was improved significantly from 0.08±0.09 logMAR (range 0 to 0.3) to 0.01±0.11 logMAR (range -0.1 to 0.3), which was not significantly different compared to control (P<0.05,P>0.05 respectively). Postoperative contrast sensitivity at higher spatial frequency (1.0, 0.7 degree) improved significantly (P<0.05,P<0.05 respectively) but still remained lower when compared to control at 0.7 spatial frequency (P<0.05). Cornea aberrations including higher-order aberrations (HOA), coma-like aberrations and spherical aberration all ameliorated but still remained worse compared to control.
Conclusions: LaserSight’s topography-guided ablation system can significantly correct decentered ablations, and improve the visual quality. However, the final results remain inferior to the eyes with originally proper central ablation.
Key words decentered ablation, retreatment, topography-guided
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