Angle Kappa in Patients with Cataracts and High Myopia

INTRODUCTION: The aim of this study was to investigate the magnitude and quadrantal distribution of angle kappa in patients with cataracts and high myopia (axial length ≥ 26 mm). METHODS: A total of 2485 patients with cataracts and high myopia and 354 patients with cataracts without high myopia (axial length < 26 mm) were included in this study. The location and value of angle kappa were determined using an Oculus Pentacam HR. An angle kappa distance exceeding 0.5 mm was defined as a large angle kappa distance. RESULTS: In high myopic eyes, multivariable linear regression analysis revealed that a larger angle kappa distance was significantly associated with longer axial length (standardized regression coefficient [β] = 0.24), narrower white-to-white (β = -0.08), lower keratometry (β = -0.08), higher corneal astigmatism (β = 0.06), and older age (β = 0.06) (all P < 0.01). The axial length cutoff point with the maximum Youden Index indicating the presence of a large angle kappa distance was 30 mm (area under the curve = 0.64). In high myopic eyes, the most common regions of angle kappa relative to the pupillary axis were the temporal-superior (40%) and temporal-inferior (26%) quadrants. However, in non-high myopic eyes, the most frequent regions were the nasal-superior (31%) and nasal-inferior (31%) quadrants. CONCLUSIONS: An axial length of ≥ 30 mm is a risk factor for the presence of an angle kappa distance greater than 0.5 mm. In high myopic eyes, the most common location of angle kappa is the temporal-superior quadrant relative to the pupil center.