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

Starting from the early 2010s [1, 2], several studies have shown that a short period of monocular deprivation in adult volunteers transiently shifts ocular dominance in favor of the deprived eye. We compiled a meta-analysis of 73 such studies that measured the effects of monocular deprivation and related manipulations, using a diverse set of techniques [1-73]. The ocular dominance shift elicited by monocular deprivation was comparable across studies where deprivation was achieved with an opaque or translucent patch and irrespectively of whether the dominant or non-dominant eye was deprived. Effects were larger and longer lasting after longer periods of deprivation. Qualitatively similar effects were produced by monocular manipulations that did not reduce the strength of the stimulus: filtering or distorting the image in one eye, suppressing it from awareness or merely making it task irrelevant. We discuss the available evidence in the light of current models and a new perspective inspired by predictive coding.