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B.K. Foutch, C.J. Bassi; The Dominant Eye: Dominant for Parvo but Not for Magno? . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4567.
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© ARVO (1962-2015); The Authors (2016-present)
Eye dominance is usually defined as a preference for the visual input of one eye to the other. Implicit in this definition is the dominant eye has better visual function. Several studies have investigated the effect of visual direction or defocus on ocular dominance, but there is little information concerning the relationship of ocular dominance to monocular visual thresholds. PURPOSE: The purpose of this study is to study the difference in contrast thresholds of the dominant vs. non–dominant eye. METHODS: The classic "hole in card" method was used to determine the dominant eye. Contrast sensitivity thresholds were then compared between the dominant and non–dominant eyes in 24 adult subjects (9 males, 15 females). Stimuli were designed to be processed more strongly either by the magnocellular (low spatial frequency, moving, non–foveal, blue–yellow) or parvocellular (high spatial frequency, non–moving, foveal, red–green) pathway. Lower contrast thresholds were predicted in the dominant eye for the stimulus designed for parvocellular processing. No difference in contrast thresholds for the magnocellular stimulus was predicted. RESULTS: There were significantly lower contrast thresholds in the dominant eye for the parvocellular stimulus (t = –2.459, p=0.022), but not for the magnocellular stimulus (t = –0.877, p = 0.390). Effect size of the significant finding was d = 0.45. There was an interaction effect of gender and stimulus type (parvocellular or magnocellular) on contrast thresholds (p = 0.03). Females were more sensitive to parvocellular stimuli (p = 0.054). There was no gender difference for magnocellular stimuli (p > 0.2). CONCLUSIONS: As predicted, there was a significant effect of the dominant eye on monocular contrast sensitivity thresholds. The dominant eye compared to the non dominant eye was more sensitive to parvocellular stimuli but not to magnocellular stimuli. This has important implications for the parallel visual pathways. There were also potential gender effects on contrast thresholds and reaction times that deserve more study.
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