Retinal-Specificity of Sensory Eye Dominance and Its Learning-Induced Improvements.

Purpose: Sensory eye dominance (SED) is typically quantified at the fovea, but there is no reason to assume it should be uniform across the visual field. Here, we asked whether SED varies across the visual field (Experiment 1) and examined whether training-induced SED changes are transferable to untrained retinal locations (Experiment 2). Methods: Forty-eight normal-sighted adults participated across two experiments (24 per experiment). A dichoptic signal-in-noise motion task was employed in both to quantify SED and to serve as the training paradigm. In Experiment 1, SED was systematically mapped at the fovea (0°) and at 16 peripheral locations, defined by two eccentricities (3° and 6°) and eight polar angles (0° to 315° in 45° increments). In Experiment 2, SED was assessed at the fovea and four peripheral sites at 7.5° eccentricity along the cardinal meridians, before and after three days of perceptual training conducted at the fovea. Results: Group-level results from Experiment 1 revealed no systematic variation in SED across the visual field. However, individuals with stronger dominance exhibited a consistent dominant eye across retinal locations, while those with weaker dominance showed more inconsistent patterns of dominance. In Experiment 2, improvements in SED after perceptual training were confined to the trained foveal location and did not transfer to untrained regions. Motion sensitivity (thresholds), however, improved across all tested retinal locations. Conclusions: The localized variability in SED, particularly among weakly dominant individuals, together with retinotopically-specific training effects, implicates early retinotopic visual areas as key substrates underlying both SED and its learning-dependent plasticity.