Longitudinal Postoperative LASIK Epithelial Thickness Profile Changes in Correlation With Degree of Myopia Correction

PURPOSE: To evaluate epithelial thickness profile changes following myopic femtosecond laser-assisted LASIK in relation to the degree of myopia corrected, evaluated with a spectral-domain anterior-segment optical coherence tomography system. METHODS: Sixty-one consecutive cases were observed for corneal epithelial thickness distribution preoperatively and at 1 day, 1 week, 1 month, and 1 year postoperatively. Epithelial thickness mapping was obtained with a spectral-domain optical coherence tomography system (Optovue Inc., Fremont, CA). Descriptive statistics investigated epithelial thickness at the central 2-mm area, the mean over the central 6- mm area, and mid-peripherally at the 5-mm ring area. RESULTS: Preoperatively, the pupil center epithelial thickness was 51.67 +/- 2.57 mu m (range: 45 to 56 mu m), mean was 51.76 +/- 2.66 mu m (range: 45 to 57 mu m), and mid-periphery was 51.78 +/- 2.71 mu m (range: 46 to 57 mu m). Compared to the preoperative values, the epithelial thickness for the center, mean, and mid-periphery was -0.30, +1.07, and +1.35 mu m at 1 week, +1.58, + 2.88, and + 3.31 mu m at 1 month (P =.0036, <.001, and <.001), and + 1.42, + 2.90, and + 3.19 mu m at 1 year postoperatively (P = 0.146, <.001, and <.001), respectively. The correlation analysis between the epithelial thickness increase and the spherical equivalent of myopic correction showed a trend toward epithelial thickness increase with the amount of myopic ablation, particularly at the mid-peripheral 5-mm area. CONCLUSIONS: In this comprehensive study of postoperative corneal epithelial thickness remodeling following femtosecond laser-assisted myopic LASIK correction, an increase at the 1-month and up to 1-year postoperative interval suggested postoperative epithelial activity in connection to the extent of ablation.