Assessing ocular dominance: rethinking the current paradigm

PURPOSE: To assess the concordance of a binary, motor sighting test of ocular dominance with a new sensory test using a simultaneous, binocular, head-mounted visual simulator to both identify and quantify the strength of eye dominance (EDS) at near and far. SETTING: 5 U.S. Private Practices. DESIGN: Prospective, multicentered, double masked, non-interventional, comparative study. METHODS: Prospective participants underwent sighting dominance testing using a 'hole-in-the-card' method through their distance refraction. Sensory testing was performed using a wearable, head-mounted, binocular, see-through visual simulator activating an optotunable lens on pupil conjugate plane, set to introduce monocular defocus for masked determination of both ocular preference and eye dominance strength (EDS) at far and at near (correcting the vergence with positive lenses). RESULTS: Of 326 subjects, strong ocular dominance was found at far and at near in 50% (N=163) and 56% (N=183), respectively, with roughly equal remaining distribution between weak and equidominance. In 41% (N=134), the eye chosen to be the dominant eye with the 'hole-in-the-card' sighting method did not match the results from the sensory dominance test. In addition, in 26% (N=85), the subject changed from right eye dominance with the 'hole-in-the-card' to left eye dominance with the sensory EDS test; and 15% (N=49) changed from left to right. CONCLUSIONS: Assignment of ocular dominance with the commonly used 'hole-in-the card' test often does not align with the patient's preferred eye using sensory testing with a visual simulator simulating monovision. Further investigation will determine whether both strength and localization of ocular dominance in planning monovision are important factors in predicting patients' satisfaction and adaptation to monovision.