정상 및 원추각막에서 각막 전, 후면의 융기 및 시상면만곡도의 비교분석

Comparison of Anterior and Posterior Elevation, and Sagittal Curvature between Keratoconus and Normal Cornea

Purpose: To compare changes of anterior and posterior corneal elevation, and sagittal curvature according to the severity of keratoconus and to compare differences between keratoconus and normal cornea. Methods: A total of 81 eyes diagnosed with keratoconus and 20 eyes of normal subjects were evaluated with a Pentacam Scheimpflug camera. The keratoconus eyes were divided into 3 groups according to mean keratometer (K): mild (K ≤ 47.0 diopters (D)), moderate (47.0 to 52.0 D), and severe (52.0 D≥). The following parameters were obtained to evaluate the correlation of keratoconus: corneal thickness, anterior and posterior corneal elevation, and sagittal curvature. Results: Out of 81 keratoconus eyes, 56 eyes were mild, 12 eyes were moderate, and 13 eyes were severe keratoconus. The mean central corneal keratometer, anterior and posterior corneal elevation, and sagittal curvature of the keratoconus eyes were 49.7 D, 22.07 μm, 38.16 μm, 52.76 D and the values increased statistically compared to the normal eyes. Furthermore, the values increased significantly with the severity of keratoconus. ROC curve analysis showed the estimated meaningful value for anterior and posterior corneal elevation and sagittal curvature of keratoconus for diagnosis; there were no diagnostic values for corneal thickness and refractive power. Conclusions: The index of 5.5 μm for mean anterior elevation, 12.5 μm for mean posterior elevation, and 44.5 μm for mean sagittal curvature using the PentacamⓇ are useful to diagnose keratoconus. Variation of anterior and posterior elevation, and sagittal curvature measured by PentacamⓇ are useful in understanding the process of keratoconus. J Korean Ophthalmol Soc 2012;53(10):1432-1437