Corneal optical coherence tomography before and immediately after excimer laser photorefractive keratectomy

Abstract

PURPOSE: To investigate the representation of the corneal structure with optical coherence tomography before and immediately after excimer laser photorefractive keratectomy. METHODS: Twenty-four eyes of 24 patients with myopia and myopic astigmatism were prospectively studied. The corneal thickness and the corneal profile were assessed with slit-lamp–adapted optical coherence tomography preoperatively and immediately after excimer laser photorefractive keratectomy. RESULTS: The attempted mean spherical equivalent of the refractive corrections was −6.7 ± 3.6 (mean ± SD) diopters with a mean calculated stromal ablation depth of 91 ± 38 μm. The corneal optical coherence tomography was reproducible in all patients, demonstrating a mean decrease of central corneal thickness after epithelial debridement and excimer laser photorefractive keratectomy of 118 ± 45 μm. The comparison of the calculated stromal ablation depth and the corneal thickness changes determined by corneal optical coherence tomography revealed a significant linear relationship with a correlation coefficient of 0.88 ( P < .001). The flattening of the corneal curvature was confirmed in all patients with the optical coherence tomography system and correlated with the attempted refractive correction (r = .82, P < .001). CONCLUSIONS: The slit-lamp–adapted optical coherence tomography system presented in this study allowed noncontact, cross-sectional, and high-resolution imaging of the corneal configuration. This initial clinical evaluation demonstrated that corneal optical coherence tomography could be a promising diagnostic modality to monitor corneal changes of thickness and curvature before and after excimer laser photorefractive keratectomy.