The Dominant Eye: Dominant for Parvo- But Not for Magno-Biased Stimuli?

Brian K Foutch,Carl J Bassi

doi:10.3390/vision4010019

Brian K Foutch, Carl J Bassi

Open Access

https://doi.org/10.3390/vision4010019

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Abstract

Eye dominance is often 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 less evidence connecting ocular dominance and monocular visual thresholds. We used the classic “hole in card” method to determine the dominant eye for 28 adult observers (11 males and 17 females). We then compared contrast thresholds between the dominant and non-dominant eyes using grating stimuli biased to be processed more strongly either by the magnocellular (MC) or parvocellular (PC) pathway. Using non-parametric mean rank tests, the dominant eye was more sensitive overall than the non-dominant eye to both stimuli (z = −2.54, p = 0.01). The dominant eye was also more sensitive to the PC-biased stimulus (z = −2.22, p = 0.03) but not the MC-biased stimulus (z = −1.16, p = 0.25). We discuss the clinical relevance of these results as well as the implications for parallel visual pathways.

Highlights

Many eye care professionals still assume pure dominance laterality in their patients; that is, in lieu of some test for eye-dominance, clinicians often assign ocular mastery to the right eye of right-handed patients and to the left eye for left-handed patients. This habit exists despite almost a century of evidence that eye dominance is unrelated to cerebral laterality or hand dominance [1–6]
Contrast thresholds were first analyzed for normality via Kolmogorov–Smirnov tests
Contrast thresholds first analyzed for normality viaand

Summary

Introduction

Many eye care professionals still assume pure dominance laterality in their patients; that is, in lieu of some test for eye-dominance, clinicians often assign ocular mastery to the right eye of right-handed patients and to the left eye for left-handed patients This habit exists despite almost a century of evidence that eye dominance is unrelated to cerebral laterality or hand dominance [1–6]. Hofeldt concluded that placing a moderate neutral density filter over the dominant eye diminished motion task performance more than placing the filter over the non-dominant or both eyes [12] These studies suggest that one eye at least guides visual direction, and it is safe to presume that eye should be assigned as the better seeing eye when balancing refractions or assigning distance and near eyes in monovision contact lens prescriptions

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