Hi.. Retinitis pigmentosa is a progressive disorder occuring due to genetic defects.. It is very sad that the treatment modalities are only to prevent the rapid progression and slow the progress of the disease... Iam not sure of Chennai, but Bangalore definitely has a few centres which are good.. You may try mnto Hospital at chamarajpet, bangalore.. Hope you find it useful...
You can try Vit A therapy.For more details visit
http://sites.google.com/site/eyediseases/Home/retinitis-pigmentosa