각막지형도 검사를 이용한 전방각 비교 연구

Iridocorneal Angle Estimation by the OrbscanTM II z Topography

Purpose: Iridocorneal angles measured by the OrbscanTM II z topography system (Bausch & Lomb) can be estimated using “plane” and “2D polynomial” modes. We compared the angle measurements between the two modes, and estimated the correlation of iridocorneal angles with other biometric measurements such as anterior chamber (A/C) depth, horizontal corneal diameter, and corneal thickness. Methods: This study comprised 100 normal eyes of 50 patients with refractive errors of -1.0 to +1.0 diopters. Iridocorneal angles were measured three times in eight meridians (0o, 45o, 90o, 135o, 180o, 225o, 270o and 315o) using both the “plane” and “2D polynomial” modes, by a single examiner. Results: Significant difference of the mean iridocorneal angles was found between the two reconstruction modes, which showed a correlation with each other. Angle measurement with the plane mode showed a significant correlation with A/C depth and horizontal corneal diameter measurement, but that with the polynomial mode showed no correlation with them. The highest reproducibility was shown at the superior location among the 8 locations. Conclusions: The iridocorneal angle, measured by the plane mode rather than the polynomial mode, especially at the superior location, should be useful for clinical application.