Angle Kappa in Patients with Cataracts and High Myopia

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).

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.

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.

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.