Distribution of angle alpha and angle kappa measured by Lenstar 900 in a Chinese population

Abstract

Abstract Purpose To describe the distribution of angle alpha and angle kappa in a Chinese population. Methods Angle alpha, angle kappa, and other ocular biometric parameters were measured by the Lenstar 900 platform. The distributions of angle alpha and angle kappa and their associations with ocular parameters were assessed. Results This study included 9272 people for a total of 18544 eyes. The alpha angles of both eyes were 0.42 (0.26, 0.53) mm and 0.41 (0.26, 0.52) mm in the right eye and left eyes, respectively. The kappa angle values of both eyes were 0.24 (0.14, 0.31) mm in the right eye and 0.23 (0.13, 0.30) mm in the left eye. Angle alpha and angle kappa are mainly located in the temporal direction of the visual axis. Angle kappa and angle alpha were positively correlated with age and lens thickness and negatively correlated with anterior chamber depth, axial length, and corneal horizontal diameter (all P < 0.001). Angle alpha is positively correlated with angle kappa, and the angle alpha and angle kappa of both eyes are positively correlated. With increasing age, angle alpha and angle kappa gradually change in a nonlinear manner. Conclusion Angle alpha and angle kappa, both predominantly located temporal to the visual axis, were influenced by age, anterior chamber depth, axial length, and corneal horizontal diameter. As age increased, the changes in angle alpha and angle kappa were nonlinear, showing a downward then upward trend, with 20–30 years as the turning point.