Effects of Extended Alternating Monocular Deprivation on the Plasticity of Visual Functions: A Single-Case Multiple-Baseline Study

This single-case study investigated the effects of alternating monocular deprivation on visual performance and plasticity in a healthy adult. Research has shown that monocular deprivation can shift ocular dominance and improve visual functions in the deprived eye. Over 24 consecutive days, a participant underwent daily sessions combining short-term eye patching and Neuro Visual Training (NVT), a Gabor based perceptual learning task, while a control participant completed the same training without occlusion. Both subjects were assessed through NVT performance, visual acuity, visual acuity with distractors, and Vernier hyperacuity, measured daily and at pre- and post-test sessions. Linear regressions and Tau-U analyses were applied to examine within- and between-phase trends. Results showed alternating fluctuations in the experimental subject aligned with the patching schedule, although not statistically significant and without cumulative improvement. The control subject showed modest, consistent enhancement across weeks. These findings suggest that alternating deprivation may induce temporary modulations in visual function. Methodological limitations and individual visual characteristics likely constrained the emergence of perceptual plasticity, while differences between subjects further limited the comparability of results.