Contrast Sensitivity Development After Extended Congenital Blindness


Kalia A, Lesmes LA, Dorr M, Gandhi T, Chatterjee G, Ganesh S, Bex PJ, Sinha P. Contrast Sensitivity Development After Extended Congenital Blindness. Proceedings of the National Academy of Sciences [Internet]. 2014;111(5):2035-2039.


Visual plasticity peaks during early critical periods of normal visual development. Studies in animals and humans provide converging evidence that gains in visual function are minimal and deficits are most severe when visual deprivation extends beyond the critical period. Here we demonstrate visual development in a unique sample of patients who experienced early onset blindness (beginning before 1 year of age and lasting 8-17 years).  before removal of bilateral cataracts. These patients show surprising improvements in contrast sensitivity, an assay of basic spatial vision. We find that contrast sensitivty development is independent of the age of sight onset once critical periods have passed, and that individual rates of improvement can exceed those of normally-developing infants. These results reveal that the visual system can retain considerable plasticity, even after early and extended blindness.