2024

Miriam Acquafredda, Irene Di Marco , Guido Marco Cicchini, Laura Biagi, Michela Tosetti, Alessandro Sale, Paola Binda, Maria Concetta Morrone

Treating adult amblyopia through combined physical exercise and inverse occlusion: evidence from 7T BOLD responses

European Conference on Visual Perception

24-29/08/2024

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While amblyopia can be ameliorated in children, treating it in adults is challenging. Among the new therapeutic approaches, combining physical exercise with short-term occlusion of the weaker eye has shown promise in improving visual acuity. Here, we tested the effects of such combined treatment on visual evoked responses in the primary visual cortex (V1) measured with ultra-high field fMRI. We studied eight amblyopic adults (aged between 16 and 44 years old), with amblyopia caused by anisometropia or infant strabismus. After a detailed ophthalmic examination, they underwent fMRI scanning at 7T. BOLD responses to five band-pass-noise monocular visual stimuli (peak spatial frequency ranging from 0.1 to 2.7 cpd), were measured before and after 2 hours of covering the amblyopic eye with a translucent patch. We repeated this protocol after a 4 week training performed at home, in telemedicine. The training was composed of six sessions (three in the first week and one in each of the following weeks) where the 2 hour patching was combined with cycling on a stationary bike. In line with our previous findings, the training improved amblyopic eye acuity by 0.10 ± 0.05 logMAR (as measured with an automated Tumbling E test). 7T BOLD responses in V1 to higher spatial frequencies were reduced for the amblyopic eye compared to the fellow eye. This dominance of the fellow eye responses decreased after the 2 hour patching and after the 4 week training. Using binocular rivalry we indexed ocular dominance and observed a reduction of the fellow eye dominance after patching and further after the 4 week training. In conclusion, treating amblyopic adults with a combination of physical exercise and short-term inverse occlusion produced a shift of ocular dominance, measured behaviorally and with 7TfMRI, and revealed a reorganization of V1-evoked responses favoring the amblyopic eye.