The Association between Ocular Dominance and Refractive Errors in Chinese Myopic Subjects

Background: To determine the association between ocular dominance and myopic anisometropia in Chinese myopic subjects. This relevance would facilitate to identify the ocular dominance in bilateral cataract patients. Design: Retrospectively case study. Participants: 1503 Chinese myopic subjects, mean age 27 years, who were candidates for corneal myopic refractive surgery were reviewed between 2011 and 2012. Methods: The ocular dominance was determined by the hole-in-the-card test. The associations between ocular dominance laterality and refractive characters, including the sphere, cylinder, spherical and astigmatic anisometropia, were analyzed. Main outcome measures: Ocular dominance, manifest refraction, cycloplegic refraction. Results: 992 (66%) subjects were right-eye dominant while 511 (34%) subjects were left-eye dominant. The dominant eyes had lower spherical equivalents (SE) and cylinders than the non-dominant eyes (-5.36 D vs. -5.48 D and -0.70 D vs. -0.76 D, respectively, P<0.001). The ocular dominance was significantly associated with the lower myopic eye in subjects with SE anisometropia >0.5 D (P<0.05). There was also significant association between the dominant eyes and the lower astigmatic eyes in the subjects with astigmatic anisometropia > 0.25 D (P<0.05). In unilateral astigmatic subjects, non-astigmatic eyes were noted to be the dominant eyes in 111 (57.51%) subjects and astigmatic eyes represented dominance in 82 (42.49%) subjects. The difference was not statistically significant (P=0.249). The ocular dominance was not associated with the sex. Conclusion: In Chinese myopic subjects, the dominant eye usually had lower myopic SE and lower astigmatism compared with the non-dominant eye, especially in subjects with high amount of anisometropia.