Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography

Abstract

Purpose: To introduce a new convenient and accurate method to measure the angle kappa using ultrasoundbiomicroscopy (UBM) and corneal topography. Methods: Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa wasmeasured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominanteye was compared with measurements by Orbscan II. Results: The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p < 0.001). The twomethods showed good reliability (intraclass correlation coefficient, 0.671; p < 0.001). Bland-Altman plots wereused to demonstrate the agreement between the two methods. Conclusions: We designed a new method using UBM and corneal topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device.