PURPOSE: To compare visual outcomes after LASIK using the VISX STAR S4 CustomVue, with and without Iris Registration technology. METHODS: In this retrospective study, LASIK was performed on 239 myopic eyes, with or without astigmatism, of 142 patients. Iris registration LASIK was performed on 121 eyes and non-iris registration LASIK was performed on 118 eyes. Primary outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and manifest refraction. RESULTS: At 6 months, the mean values for UCVA (logMAR) were 0.00±0.09 in the iris registration group and -0.01±0.11 in the non-iris registration group (P=.587). Seventy-nine percent of eyes in the iris registration group had UCVA of 20/20 or better compared to 78% in the non-iris registration group (P=.518). Ninetytwo percent of eyes in the iris registration group and 90% in the non-iris registration group were within ±0.50 diopters (D) of emmetropia (P=.999). Mean postoperative absolute change in total root-mean-square higher order aberrations in the iris registration group and noniris registration group was 0.22 μm and 0.19 μm, respectively (P=.6). At 3 months, the mean magnitude of error of surgically induced astigmatism was -0.09 in the iris registration group and -0.04 in the non-iris registration group (P=.25). CONCLUSIONS: Wavefront-guided LASIK with the VISX STAR S4 CustomVue laser system, independent of iris registration status, is effective, safe, and predictable. Under well-controlled surgical conditions, this study did not fi nd any statistical signifi cance supporting the better achievement of visual acuity, astigmatism correction, or the lesser induction of higher order aberrations using iris registration in comparison to a non-iris registration system.
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