Visual Outcomes and Induction of High Order Aberrations after Myopic Wavefront-guided LASIK: Effect of Iris Registration

Purpose: To determine the amount of cyclotorsion and pupil centroid shift and to compare visual outcomes and induction of high order aberrations (HOA) between wavefront-guided LASIK with and without iris registration (IR). Methods: Retrospective chart review of subjects who underwent myopic custom LASIK (CustomVue, AMO). Eyes were divided into 2 groups based on IR: group 1, IR not enable (CV); and group 2, IR enabled (IR). Cyclotorsion, pupil centroid shift, visual outcomes, and induction of high order aberrations were evaluated and compared between the groups. Results: A total of 221 eyes of 147 subjects were included in the analysis: CV, n=73 and IR n=148. Mean age was 37.7±11.6 years and 35.8±11.0 years in CV and IR groups, respectively. The mean follow up was 42.7±31.2 days in the CV group and 47.8±40.4 days in the IR. Mean preoperative spherical equivalent was –3.19D±1.34 (–1.12 to –6.00) and –3.60D±1.44 (–0.62 to –6.00) in CV and IR groups, respectively. Mean cyclotorsion was 3.5°±2.4 and 92% of shift was nasal. 84% of eyes in the registration group had UCVA of 20/20 or better compared 75% of those without registration. The IR group showed approximately 50% less induction of HOA. Conclusion: Registration with cyclotorsion and pupil centroid shift compensation seems essential to further improve outcomes.