Comparison of Simulated Keratometric Changes Following Wavefront-Guided and Wavefront-Optimized Myopic Photorefractive Keratectomy.

Abstract

To determine the relationship between change in simulated keratometry and corrected refractive error in both wavefront-guided and wavefront-optimized myopic photorefractive keratectomy (PRK), and to determine whether there is a difference in this relationship between these two ablation profiles. Sixty-eight patients received wavefront-guided PRK in one eye and wavefront-optimized PRK in the contralateral eye. The changes in simulated keratometry and corresponding refractive changes for both were determined at 1 year postoperatively. Linear regression was employed to calculate the slope of change in simulated keratometry (ΔK) for change in refractive error (ΔSE) for both wavefront-guided and wavefront-optimized PRK and compared. The mean ratio ΔK/ΔSE was also calculated for both wavefront-guided and wavefront-optimized PRK and compared. There was no significant difference in the ratio of ΔK to ΔSE between wavefront-optimized and wavefront-guided PRK by both linear regression modeling and comparison of the mean ratio ΔK/ΔSE. Linear regression modeling revealed that the ratio of ΔK/ΔSE was greater for small amounts of change in refractive error and smaller for large amounts of change in refractive error. This trend was only statistically significant for the wavefront-optimized group when comparing the means of the ratio ΔK/ΔSE (P = .0287). The change in corneal curvature induced for a given degree of refractive correction was similar for both wavefront-optimized and wavefront-guided PRK. For both, a proportionally smaller amount of corneal flattening was required for larger degrees of refractive correction compared to smaller degrees. [J Refract Surg. 2016;32(8):542-548.].