The correlation between angle kappa and ocular biometry in Koreans

To investigate normative angle kappa data and to examine whether correlations exist between angle kappa and ocular biometric measurements (e.g., refractive error, axial length) and demographic features in Koreans.

Data from 436 eyes (213 males and 223 females) were analyzed in this study. The angle kappa was measured using Orbscan II. We used ocular biometric measurements, including refractive spherical equivalent, interpupillary distance and axial length, to investigate the correlations between angle kappa and ocular biometry. The IOL Master ver. 5.02 was used to obtain axial length.

The mean patient age was 57.5 ± 12.0 years in males and 59.4 ± 12.4 years in females (p = 0.11). Angle kappa averaged 4.70 ± 2.70 degrees in men and 4.89 ± 2.14 degrees in women (p = 0.48). Axial length and spherical equivalent were correlated with angle kappa (r = -0.342 and r = 0.197, respectively). The correlation between axial length and spherical equivalent had a negative correlation (r = -0.540, p < 0.001).

Angle kappa increased with spherical equivalent and age. Thus, careful manipulation should be considered in older and hyperopic patients when planning refractive or strabismus surgery.