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Author Spotlight: Assessment of Visual Acuity in Central Vision Loss Through Motion-Based Peripheral Vision Testing
Published on: February 23, 2024
Theta burst stimulation in adults with symmetric and asymmetric visual acuity
Ana Rita Tuna1, Nuno Pinto2, Andresa Fernandes2
1Faculty of Health Sciences, CICS-Health Sciences Research Centre, University of Beira Interior, Rua Marquês D'Ávila e Bolama, 6201-001, Covilhã, Portugal. anaritatuna@gmail.com.
Purpose:
Theta Burst Stimulation can influence adult neuro-visual response in imbalanced visual pathways, possibly by influencing cortical excitability. Our objective was to compare suppressive imbalance (SI) and visual acuity (VA) after applying repetitive Transcranial Magnetic Stimulation between groups of subjects with normal binocular vision, visual asymmetry, and amblyopia.
Methods:
Thirty-five volunteers between 19 and 51 years of age were split into three groups: 6 volunteers with asymmetric VA (group A); 19 amblyopes (group B); and 10 subjects with normal binocular vision (group C). VA and SI of all groups were evaluated before and after a single session of continuous Theta Burst Stimulation (cTBS) or placebo stimulation over the right occipital cortex.
Results:
In both groups A and B, we found a significant VA improvement in the non-dominant eye after cTBS (p = 0.04 and p = 0.01, respectively). In SI evaluation, group A and group B also revealed a significant improvement after the cTBS session (p = 0.03 and p = 0.01, respectively). Finally, in the group of volunteers with normal binocular vision and for placebo groups A and B, there were no significant differences in VA and SI after cTBS.
Conclusions:
Amblyopic and visually asymmetric individuals improved VA and SI of the non-dominant eye after cTBS when compared to baseline and to placebo stimulation. These enhancements were not found in the group of volunteers with normal binocular vision. We can therefore reasonably assume that cTBS may interfere with the visual system of subjects that present some kind of asymmetry, possibly by improving neuronal imbalances.
