The blind can see: Indian science sheds light

Poverty and neglect mean that only half the cases of curable blindness in India are treated. Yet this is also where doctors and patients are revolutionising one of the most basic concepts of visual neuroscience.

In this article, Apoorva Mandavilli describes the work of Project Prakash, run by Pawan Sinha, a neuroscientist from the Massachusetts Institute of Technology in the United States, in collaboration with Dr Shroff’s Charitable Eye Hospital in New Delhi, India.

Conventional medical knowledge says that if a child's blindness is not treated before they turn eight, they will be blind for life. That cut-off point was thought to be the end of the critical period for the development of the visual brain.

Sinha's work dramatically challenges this notion.

The sight of one 29-year-old patient has improved dramatically since July 2004. The extent to which his brain has adapted, allowing him to piece together patches of colour and brightness and recognise them as objects, has amazed scientists.

Sinha's work with blind people has shown the brain can learn to use what vision it has, and different visual abilities — such as understanding colour and dimension — might develop over different periods of time.

Since 2003 Project Prakash has screened hundreds of children for sight problems and, crucially, undermined the notion of irreversible blindness.