The Effect of Ocular Dominance on Accommodation and Miosis under Binocular Open Viewing Conditions

Background/Aims: We investigated the relationship between ocular dominance and accommodation on the pupils of the dominant eye and the non-dominant eye under binocular open viewing conditions. Methods: Seventeen healthy young volunteers participated in this study. The dominant eye was determined using the hole-in-the-card test. The objective refraction and pupil diameter were measured under binocular open viewing and monocular single viewing conditions using a binocular open auto-refractor, the WAM-5500 (SHIGIYA MACHINERY WORKS LTD., Hiroshima, Japan). The accommodative response was calculated using the objective refraction, and the rate of miosis was calculated using the pupil diameter. These values were then compared between the dominant and the non-dominant eyes. Results: Under binocular open viewing conditions, the accommodative response in the dominant eye was greater than in the non-dominant eye (p = 0.001). In contrast, under monocular single viewing conditions, there were no differences in the accommodative response between the dominant and non-dominant eyes. In both binocular open viewing and monocular single viewing conditions, there were no differences in the miosis ratio between the dominant and non-dominant eyes. Conclusion: These results suggest that the accommodative response under binocular open viewing conditions is influenced by ocular dominance.