2025

Cecilia Steinwurzel, Giacomo Pennella , Claudia Lunghi , Paola Binda

Short-term monocular deprivation in adult humans: a meta-analysis and new perspectives

Vision Sciences Society

20-20/05/2025

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Few hours of monocular deprivation in adult humans results in a transient shift of ocular dominance in favor of the deprived eye. This robust phenomenon has been investigated with several methodologies in 75 studies since 2011. We compiled a metaanalysis of these studies, structured following the PRISMA checklist and selectively including studies on healthy humans. Each study includes multiple experiments (approximately 180); for each, we computed a standardized effect size and, where possible, we quantified the decay rate of the effect. In the majority of studies, deprivation was achieved by covering one eye with an opaque or a translucent patch, with comparable outcomes (two-sample t(108) = -0.02, p = 0.98). Deprivation effects were mainly measured with three types of tasks: binocular cooperation, binocular competition, and monocular thresholds. Effects are larger when measured with binocular cooperation compared to binocular competition (two-sample t(100) = 4.66, p = 0.001), possibly reflecting different time windows used to report the average effects. Longer periods of deprivation induce larger (r(107) = 0.32, p = 0.001) and longer lasting effects (r(38) = 0.38, p = 0.020). Patching either eye (dominant or nondominant) does not significantly affect the outcome (two-sample t(98) = -0.74, p = 0.46). Effects are seen for both eyes; however, pooling data across studies, we find that opaque patching primarily triggers a suppression of the non-deprived eye, while translucent patching primarily boosts the deprived one (paired t(31) = 2.99, p = 0.005). A growing number of studies show that monocular deprivation effects can be mimicked by manipulations that do not impact the strength of the monocular signal, including degradation of image quality (pink noise, kaleidoscope), image inversion in space or time, or monocular delay. We conclude that the observed shift in eye dominance results from a complex interplay between bottom-up visual stimulation and top-down signals.