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Yuri Ostrovsky, Aaron Andalman, Pawan Sinha; Acquisition of visual function after extended congenital blindness. Journal of Vision 2004;4(8):190. doi: 10.1167/4.8.190.
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© ARVO (1962-2015); The Authors (2016-present)
It is well accepted that humans acquire visual function through a combination of innate and learning-based processes. The first few years of life are believed to be critical in this regard. Animal studies suggest that visual deprivation during this period can have profound consequences, leaving subjects functionally blind with no chance of recovery. However, very little human data exist on this issue. Given enough time, can a person who has suffered several years of congenital blindness acquire visual skills? Here we present a case study that addresses this question. We describe a subject, SRD, who was born blind in a village in west India and remained so until the age of 12 years, at which point her dense congenital cataracts were surgically removed. We evaluated her performance on an extensive battery of visual tasks 18 years after her surgery. The experimental battery included tests of 2D/3D shape matching, visual search, attending to objects in dynamic displays, classical illusions and face perception. We found that although SRD's visual acuity has been relatively poor since surgery, her performance on mid/high-level visual tasks is close to normal (with some interesting exceptions in the domain of gaze estimation). These results suggest that the human brain retains an impressive capacity for visual learning well into late childhood. They have implications not only for our conceptions of cortical plasticity, but also for the design of rehabilitation programs for patients who have been treated for childhood blindness. This case study is a component of Project Prakash (Sinha, VSS 2003), a large-scale undertaking dedicated to the study and eradication of childhood blindness in the developing world.
The John Merck Foundation, the Alfred P. Sloan Foundation, and the Carroll L. Wilson Award
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