Determination of ocular dominance and its association with handedness

Purpose: Clinical relevance of ocular dominance [OD] lies in its role in success of monovision. This study aims to determine easy and reliable methods to test OD and association of OD with handedness. Methods: Prospective study of 300 patients, with best corrected visual acuity of 6/6, interocular difference of < 1Dioptre, and absence of any ocular, oculomotor or binocular abnormalities. Two subjective tests were done to determine OD - Miles [sighting dominance] and Fogging tests. Handedness was determined by history. Ambidextrous patients and those unable to understand or giving equivocal replies, were excluded. Kappa [k] statistics [inter test agreement], and Chi-Square test and Odds ratio [association between handedness and ocular dominance] were applied. Results: Mean age 35.28 years, spherical equivalent refractive error ranged +2 and -6 D. Both tests had perfect agreement [k=1]. 67.33% patients were Right Ocular Dominant (ROD) whereas 32.67% were Left Ocular Dominant. 65.67% had matched dominance of eye and hand. No significant association between handedness and ocular dominance. Conclusion: Mile's and Fogging tests are reliable and easy to perform in clinical setting. Since no direct analogy could be established between patterns of eye – hand dominance, assumption of OD cannot be made on the basis of handedness. As 94.33% patients were Right Handed whereas 67.33% were ROD, the results could not be directly extrapolated in patients with dense cataracts where OD cannot be conclusively determined.