Longitudinal evaluation of posterior corneal power by anterior segment optical coherence tomography 18 months or more after photorefractive keratectomy.

PURPOSE: To investigate the change in anterior, posterior, and net corneal power more than 18 months after photorefractive keratectomy (PRK) by RTVue anterior segment optical coherence tomography (OCT). SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective observational study. METHODS: PRK was performed using Technolas TENEO 317 laser platform. Anterior, posterior, and net corneal power was measured by the RTVue-XR anterior segment OCT system with the Pachymetry + Cpwr scan pattern at baseline and 1, 3, 6, 12, 18, and >18 (up to 27) months after PRK. RESULTS: Three hundred and twenty-six eyes of 163 patients (age: 29.71 years [range, 18.5 to 46.5 years), male/female: 61 [37.4%]/102 [62.6%]) were enrolled in this study. Mean preoperative spherical equivalent was -3.15 ± 1.50 diopter (D) (range: -8.37 to -0.62 D). The mean change in net corneal power was 3.052 D, 3.281 D, 3.324 D, 3.114 D, 3.446 D, and 3.972 D at 1, 3, 6, 12, 18, and >18 months after surgery compared with baseline, respectively (P 0.1) except for 1 month after surgery, which increased 0.13 D (P<0.001). Changes in posterior corneal power were not correlated to any of the preoperative clinical and Scheimpflug variables. CONCLUSIONS: Posterior corneal power did not change for more than 18 months after PRK, except for an early small increase at 1 month postoperatively.