NYU Abu Dhabi study reveals brain structure behind vision restoration in blind teens

Quick facts:

• Congenital cataracts are the leading cause of treatable blindness in children worldwide. In countries where surgery is common, surgery is performed in infancy, and the prognosis for recovery of visual function is good.
• It is widely believed that the window for surgical intervention in congenital cataracts closes when children are 6 to 8 years old, because that is a critical period for visual brain development. The benefits of restoring visual input later in life are generally thought to be limited because the brain lacks sufficient plasticity to adapt and utilize input from the eyes.

Abu Dhabi, UAE, May 1, 2023: A team of researchers at NYU Abu Dhabi, led by Bas Rokers, director of the NYU Abu Dhabi Center for Neuroimaging, has studied changes in the brain that lead to improved visual skills. Investigators are working with Project Prakash, a combined humanitarian and scientific effort to restore sight to children with curable blindness in rural India. They found that improvements in visual function were associated with changes in white matter pathways, which connect neurons in different brain regions.

They looked at many pathways, but only those involved in higher-level visual functions, such as facial recognition, were directly associated with improved vision. In addition, the researchers found that the amount of changes in the patient’s late visual pathways, specifically the posterior callosal pincer, predicted the degree of behavioral improvement. This is a new result that pinpoints the location of the brain changes responsible for behavioral improvement.

In a paper titled “White Matter Plasticity Following Cataract Surgery in Congenitally Blind Patients,” published in the Proceedings of the National Academy of Sciences (PNAS), the researchers also confirmed that cataract surgery had a greater impact on visual function and vision. Brain plasticity if done at a younger age, but recovery is still possible even when eye surgery is done in late adolescence.

The results suggest that puberty remains sufficient plasticity after a critical period of visual development to allow patients to partially overcome abnormal visual development and help localize neural changes for recovery in blind adolescents. Thus, there exists a wider time window than previously thought during which vision restoration surgery can improve visual perception by altering structural brain plasticity. The team’s research elucidates the definition of sites of neural change associated with vision restoration, which could guide the development of treatments that attempt to induce neuroplasticity through behavioral and surgical interventions.

“The new insights discovered by our team challenge the recognized limitations of vision restoration surgery, creating opportunities for expanded use of these procedures that will make more cases of blindness treatable around the world,” Rokers said. “Our work also provides evidence to support calls for the scientific community to reassess the critical period of visual development in adolescents.”