Neuroscientist Pawan Sinha gave an inspiring talk to TED India about his work on providing treatment for visual problems and how this is over-turning many of our long-standing assumptions about how the brain develops the ability to make sense of the visual world.
Sinha focuses on children and adults who have grown up with congenital cataracts – a clouding of the eye’s lens that prevents light from entering the eye.
In essence, it’s like growing up with a blindfold on or while wearing very clouded glasses. The condition is easy to treat with minor surgery but removing the cataract ‘blindfold’ after childhood doesn’t give the personal normal vision.
This is because we are not born ‘seeing’ like we do in later childhood, the brain learns to do so in the early years of life through having experience of the visual world. For example, being able to separate objects from their background is something the brain learns to do – so we can tell that there is a postbox in front of the wall and not that there is a wall with a picture of a postbox on its surface.
Without this experience the visual system doesn’t acquire these abilities and so people who have cataracts removed later in life typically do not have normal vision – despite their eyes being restored to full function.
It was thought if cataracts were removed in late childhood the person would be stuck with missing visual skills, even though their sight would improve in some areas. However, Sinha and has team published an important study in 2006 on a woman who had cataracts removed at the age of 12, well past the time where vision was assumed to be salvageable, but who had near normal vision twenty years after her surgery.
This suggested to the research team that visual development can happen later in life and wasn’t fixed in the early years, as had been assumed from animal studies or from assessments of patients that had only happened shortly after surgery.
Sinha runs Project Prakash that provides cataract surgery to people in India but this has also allowed him the opportunity to study visual development in more detail and his TED talk is on how is combining both the humanitarian and scientific mission to expand our understanding of the visual brain and advance treatments for visual problems.