To evaluate differences between dominant and non-dominant eyes by analyzing angle kappa in dominant and non-dominant eyes.

Fifty-seven subjects who had best corrected visual acuity 20/20 in the better-seeing eye and no underlying ocular disease were recruited. Ocular dominance was determined using the hole-in-the-card test. Corneal topography, refractive error, intraocular pressure (IOP), and axial length were evaluated in both eyes.

On corneal topography examination, the angle kappa and white-to-white measurements were significantly smaller in the dominant eye than the non-dominant eye ( p = 0.013 and p = 0.045, respectively). However, no significant differences in sim K's' astigmatism ( p = 0.210), central corneal thickness ( p = 0.533), and anterior chamber depth ( p = 0.216) were observed. In addition, cylindrical powers of the subjects measured by autorefraction (AR) were significantly lower in the dominant eye ( p = 0.026); however no differences in spherical equivalent measured by AR ( p = 0.061), IOP measured using pneumonic tonometer ( p = 0.536), or axial length measured using laser biometry ( p = 0.093) were observed.

In this study, we found the angle kappa a new factor in determining the dominant and non-dominant eye. Difference in axial length and spherical equivalent between dominant and non-dominant eye may be associated with the difference in angle kappa.