In the common vision disorder amblyopia, impaired vision in one eye during development causes neural connections in the brain’s visual system to shift toward supporting the other eye, leaving the amblyopic eye less capable even after the original impairment is corrected. Current interventions are only effective during infancy and early childhood while the neural connections are still being formed.
But a new National Eye Institute-funded study in mice by neuroscientists in The Picower Institute for Learning and Memory at MIT shows that if the retina of the amblyopic eye is temporarily and reversibly anesthetized just for a couple of days, the brain’s visual response to the eye can be restored even in adulthood.
The findings, published in Cell Reports, may improve the clinical potential of the idea of temporarily anesthetizing a retina to restore the strength of the amblyopic eye’s neural connections.
In 2021 the MIT lab of Mark Bear, Ph.D., and collaborators showed that anesthetizing the non-amblyopic eye could improve vision in the amblyopic one—an approach analogous in that way to the treatment used in childhood of patching the unimpaired eye. That 2021 findings have now been replicated in adults of multiple species. But the new evidence on how inactivation works suggests that the proposed treatment also could be effective when applied directly to the amblyopic eye, Bear said, though a key next step will be to again show that it works in additional species and, ultimately, people.
“If it does, it’s a pretty substantial step forward because it would be reassuring to know that vision in the good eye would not have to be interrupted by treatment,” said Bear, a faculty member in MIT’s Department of Brain and Cognitive Sciences. “The amblyopic eye, which is not doing much, could be inactivated and ‘brought back to life’ instead. Still, I think that especially with any invasive treatment, it’s extremely important to confirm the results in higher species with visual systems closer to our own.”
To continue reading, visit the Picower Institute News.