Binocular sighting ocular dominance changes with different angles of horizontal gaze.

ABSTRACT

BACKGROUND AND PURPOSE: Ocular dominance testing is generally carried out in the primary position. A change of eye dominance when viewing in the contralateral field of horizontal gaze has recently been reported. The purpose of this study was to determine whether this occurs with other tests of eye dominance. METHODS: Ten right handed females (mean age 21.6 +/-0.8 years) with normal binocular single vision and right eye ocular dominance in primary position were tested for ocular dominance on three tests (pointing, hole-in-card, Miles ABC) performed fixing at positions at 10 degree intervals from 40 degrees left gaze to 40 degrees right gaze, with the head stationary. Four trials were undertaken in each position for each test. RESULTS: Not all participants showed a change in dominance in left gaze on all of the tests. However, a change did occur at a median of 30 degrees for the hole- in-card and Miles ABC tests and 20 degrees for the pointing test. Examining the position of change across the 3 tests, a borderline "statistically significant" difference occurred (p=0.055, Friedman test). A "statistically significant" difference was shown between the hole-in-card and pointing tests (p=0.041, Wilcoxon signed ranks test). For pointing versus Miles ABC, p=0.084; and hole-in-card versus Miles ABC, p=0.705. CONCLUSIONS: A change in eye dominance occurs when viewing in the contralateral field. Differences may exist in the angle at which this occurs due to the different conditions of the various tests for ocular dominance.