Objective Evaluation of Planned Versus Achieved Stromal Thickness Reduction in Myopic Femtosecond Laser-assisted LASIK.

PURPOSE: To evaluate corneal stromal thickness reduction and compare to attempted and achieved ablation depth in a consecutive case series study of myopic LASIK.

METHODS: Stromal thickness reduction was retrospectively evaluated in 205 consecutive eyes of 205 patients undergoing myopic and myopic astigmatic LASIK. Anterior segment optical coherence tomography was performed preoperatively and 3 months postoperatively. Epithelial thickness remodeling was also accounted for to achieve objective stromal thickness reduction. The derived maximum stromal thickness reduction was then compared to the programmed (planned) maximum ablation depth. Deviation of planned versus achieved maximum stromal thickness changes was correlated with residual refractive error.

RESULTS: The 3-month stromal reduction was 86.01 ± 28.28 µm, compared to the average programmed maximum ablation depth of 88.48 ± 26.05 µm. The attempted versus achieved thickness outliers correlated with deviations in achieved refractive correction.

CONCLUSIONS: Actual objective stromal thickness reduction following myopic LASIK correlates well with the attempted versus achieved refractive change.