Neuroscientist brings light
to the blind — and to vision research
Pawan Sinha is working to treat blindness among India’s poorest children and in the process is
discovering how the brain learns to see.
BY LEA WINERMAN
In the United States, a child born with cataracts would have a simple surgery
to correct the condition soon after birth.
But infants born to India’s poorest
families don’t have access to that surgery
— and so they grow up blind, unable
to attend school and, in many cases,
sentenced to a life of begging.
A decade ago, MIT neuroscientist
Pawan Sinha, PhD, realized that giving
these children sight-restoring surgeries
could also advance science. By studying
how these older children learn to see
after a decade or more in the dark, he
could elucidate the mechanisms that
underlie vision in all of us.
Today, Sinha’s Project Prakash
(“light” in Sanskrit) has treated more
than 400 children and helped answer a
300-year-old question about how our
senses of vision and touch interact. Sinha
spoke to the Monitor about his research
and his plans to reach thousands more
children in the years to come.
How did you come up with the
idea for Project Prakash?
I think the seed of the scientific idea was
already in my mind when I was starting
my faculty position at MIT.
This question — how does the brain
learn to see? — has been extremely
difficult to address experimentally. The
only approach that we have is to work
with either very young animals or, in the
human case, to work with infants. But by
the time infants are even minimally able
to respond — say they are a few months
old — we have missed many very
important changes. So I was struggling
with this question.
Then on a trip to India in 2002 to
visit my father, who lives in New Delhi,
I saw these little children begging on the
streets. That itself is a very distressing
sight, but what was even more disturbing
was the fact that some of these children
had treatable disabilities. A couple of
the children I saw were blind because of
cataracts, and even though I’m not an
ophthalmologist, I knew that this is a
I realized that if I were to try to do
something just on a personal scale, I
would be able to provide funding for the
surgeries of a handful of these children,
which would be satisfying but would not
really begin to make a dent in the larger
scope of the problem.
And that’s when I realized that the
scientific question I’d been struggling
with found almost a perfect approach in
the treatment of these children. If you
have a child who’s, say, 10 years old, who
has been blind since birth, and in this
child you are able to initiate sight, then
you have an unprecedented opportunity
to examine visual development, right
from point zero.
Once I had that realization, then the
path forward became reasonably clear.
As a scientist I know how to define a
scientific problem and how to approach
scientific grant-making bodies. So I
could describe to them the humanitarian
crisis and the scientific benefits to be
derived by addressing this humanitarian
crisis. Funding bodies like NIH, and
some private foundations, responded
very well to that combination.
What have you learned from your
research about the development
of human sight?
Some of the first questions that we
addressed had to do with a child’s ability
to interpret an image as a collection
of objects. If I give you a marker and
an image, you would have no problem
delineating the boundaries of the objects
[in the picture].
But even that very basic task of
breaking up an image into distinct
entities is shrouded in mystery. How
does the brain do that? If you try to get
a computer to do the same thing, it fails
catastrophically. And that says something
about just how difficult this problem is,
notwithstanding the fact that we are able
to do it so easily.
What we found was that in the
initial stages of visual learning — let’s
say you have a child who has been
treated just a few days ago — that child
tends to break up the visual image into
many more pieces than a normally
sighted person would. Little things like
shadows become distinct objects. It’s
only over time that the child begins to
understand the correct parsing of an