Visual Performance after Wavefront-guided and Wavefront-optimized Photorefractive Keratectomy (PRK) and Laser in situ keratomileusis (LASIK)

Abstract

Purpose: To compare visual acuity and contrast sensitivity results after wavefront-guided (WFG) and wavefront-optimized (WFO) PRK and LASIK.

Methods: This was a prospective study of 213 myopic US military personnel undergoing either PRK or LASIK randomized to either WFG or WFO treatment. WFG surgeries were performed using the VISX Star S4 (Abbott Medical Optics) and WFO surgeries with the Wavelight Allegretto Wave Eye-Q (Alcon Surgical). Outcome measures included corrected distance high contrast visual acuity (HCVA) and small letter (20/25) contrast sensitivity (CS) measured with the SuperVision back-illuminated letter; corrected low contrast visual acuities (LCVA) using 5% low contrast chart under photopic condition and 25% low contrast chart under photopic and mesopic conditions; and night vision assessed with the 25% low contrast chart viewed through a dark green night vision filter. Tests were performed at preop and at 1, 3, and 6 months postop. Repeated measures analysis of variance was used to compare the groups over time. A p-value <0.05 was considered statistically significant.

Results: U.S military personnel aged 30.8 years ±6.8 with manifest spherical equivalent -3.61 diopters ±1.53 participated in this study. A statistically significant difference was seen among the treatment groups in 5% LCVA under photopic condition (p=0.04) and 25% LCVA under mesopic condition (p=0.02). Performance under the follow testing conditions did not reach statistical significance: SuperVision HCVA (p=0.63), SuperVision CS (p=0.05), 25% LCVA under photopic condition (p=0.44) and nigh vision performance (p=0.32).

Conclusions: Visual acuity and contrast sensitivity up to the 6 months postoperative period did not appear to have a discernible association to the refractive surgery performed, whether the surgery was PRK or LASIK, on either WFG or WFO excimer laser platform.

Keywords: 679 refractive surgery: comparative studies • 682 refractive surgery: other technologies • 478 contrast sensitivity