Comparison between Wavefront Guided and Wavefront Optimized LASIK as regards the Functional Optical Zone

Abstract

PURPOSE: To compare between wavefront-guided (WFG) and wavefront-optimized (WFO) LASIK as regards functional optical zone (FOZ) in patients with myopia and myopic astigmatism. METHODS: This is a prospective, comparative study. One hundred myopic eyes of 50 patients (± astigmatism) were divided into 2 groups according to laser platform; WFO & WFG where femtosecond assisted LASIK was performed. Using Holladay Equivalent K Reading (EKR) report of Pentacam; FOZ was defined as zone centered on pupil center with standard deviation 0.5D around mean EKR. Three months postoperatively differences in FOZ between two ablation patterns were analyzed. Visual acuity, refractive error, corneal asphericity (Q-value) and higher order aberrations root mean square (HOA RMS) error were evaluated. RESULTS: Mean patients age was 26.64±5.67 years. Preoperative characteristics of eyes in 2 groups were not significantly different (P > 0.05). Intended optical zone (IOZ) was 6mm in both groups. Mean laser ablation depth was greater in the WFG (18 µm per diopter) than in WFO group (16µm per diopter) (P=0.035). After 3 months, FOZ diameters were 4.32±0.94 (71.99 ± 15.68 % of IOZ) for WFO & 4.16±1.13mm (69.33 ± 18.78 % of IOZ) for WFG, with no significant difference between 2 groups (P=0.622). Induced change in corneal asphericity was greater in WFG (P=0.034). Postoperative mean uncorrected distance visual acuity, manifest refraction, HOA showed no significant difference (P >0.05). CONCLUSION: No significant postoperative difference was found between the WFO and WFG LASIK groups in FOZ size, refractive outcomes, HOA. Whereas, ablation depth and change in corneal asphericity were significantly greater in the WFG group.