The Gift of Sight and the Science of Seeing
Ten years ago, Pawan Sinha was visiting his father in Delhi when he noticed a startling and tragic sight: young children, many of them maimed or blind, begging on the streets. He could tell that many of the blind children had cataracts—a condition that can be corrected easily through surgery.
Sinha, an MIT professor of brain and cognitive sciences who studies vision, immediately saw a chance to help those children and, at the same time, further his research on brain development. He had been looking for a way to investigate how the brain learns to make sense of visual input from the eyes, a question that neuroscientists have traditionally probed by studying babies. Babies, however, are usually not coöperative research subjects, limiting the value of such studies.
The ideal subjects, Sinha realized, would be people born blind who later gained sight. “It very quickly struck me that in providing these children with sight surgery, we would also have the answer to the question that I had been struggling with,” he says. “That confluence of being able to do something that would directly impact the lives of children, and also make headway into scientific questions, was a very attractive possibility.”
In 2005, Sinha launched Project Prakash to find children with curable forms of blindness and offer them free treatment. Since then, the project has screened more than 28,000 children, both in Delhi and in remote Indian villages, and nearly 2,000, including 162 with congenital blindness, have been treated for a variety of eye problems. By studying some of those children after surgery, Sinha and his colleagues have answered many questions about how the brain learns to see. Their findings have also influenced how certain forms of blindness are treated in India and elsewhere.
A preventable tragedy
India has an extremely large population of blind children; estimates range from 200,000 to more than a million. The rate of childhood blindness in developing countries is five times that in more affluent nations, and the World Health Organization says that in India, more than half of all congenitally blind children die before the age of five. Those who do survive have extremely limited opportunities: across the developing world, 90 percent go uneducated. In India, even those who attend schools for the blind get a minimal education that does not come close to preparing them for well-paying jobs. They might learn to count, for example, but typically get no further math instruction. Fewer than 1 percent of blind people in India are employed as adults.
Most treatable cases of blindness involve either cataracts or corneal scarring, which is often caused by vitamin A deficiency. Both can be repaired with surgical procedures that in developed countries are considered routine: cataracts can be removed, and scarred corneas can be replaced. In rural India, however, children with these conditions usually remain blind.
“In the United States, if I were to find one such untreated child, it would be headline news,” says Sinha. “But in India, because most of the children are born in their homes, they hardly have any contact with modern medical care.” Indeed, fewer than 20 percent of blind children in India receive treatment, says Sinha, though twice that many have conditions that could be cured. Fewer than 15 percent of India’s major hospitals have pediatric ophthalmic units, and most of the existing facilities are located in cities, with little access for rural villagers.
Project Prakash (prakash is the Sanskrit word for light) sends teams of optometrists and ophthalmologists to villages far from Delhi looking for children who can be helped. Visiting those villages has been a revelation for Sinha. Growing up in Delhi, where his father was an administrator at the Indian Institute of Technology (IIT), he was shielded from the poverty that grips most of rural India.
“Even though I grew up in India, I hadn’t really appreciated how much of the country lives,” says Sinha, who usually returns twice a year. “It’s a very sobering realization that in a country that we think is developing so well, the reality seems to be very different when you go to the villages.”
Richard Held, an MIT professor emeritus of brain and cognitive sciences who accompanied Sinha on a 2008 trip to India and coauthored two papers on Project Prakash research, says the villagers are welcoming and curious about the newcomers. “Everybody comes out and looks at us. We’re on exhibit, because they don’t see too many visitors,” he says. Sinha, who is fluent in Hindi, easily establishes a rapport with the residents, says Held. “He’s a very generous person and wise in the ways of people, as well as being a good scientist,” he says.
A gradual process
The Project Prakash teams usually end up screening 100 to 200 children per village. Any good candidates for surgery are invited to come to Delhi, where they can be treated at a facility called Dr. Shroff’s Charity Eye Hospital, Project Prakash’s main partner in India. Project Prakash, which is funded in part by the U.S. National Institutes of Health, pays for the surgeries and transportation costs, covering lost wages for the children’s parents as well.
Although cataract removal and corneal replacement had been done on infants in developed countries, such surgeries had rarely been performed on older children who had been blind from infancy, so the researchers weren’t sure what to expect. Yuri Ostrovsky, PhD ’10, who helped Sinha launch the project, recalls that in the beginning, he believed the most exciting moment would be removing the bandages after a congenitally blind patient’s surgery. “We got ready for that moment, and we asked them, ‘How does the world look now?’ And they said, ‘Pretty much the same,’” says Ostrovsky, now a postdoc in Sinha’s lab. “That was a little surprising and maybe, in some ways, a little bit of a letdown.”
By testing the children on visual tasks such as distinguishing between colors and identifying shapes, the researchers discovered that immediately following surgery, patients’ eyes can detect only light and some degree of color. That is, they can track a light source and determine that a green patch is different from two red patches (though they don’t know the colors by name). Their brains have not yet learned to process more complex images such as faces. “Their ability to understand what’s what—that takes time,” Sinha says. “A month for some tasks, longer for others.”
The tests on the children’s visual progress—performed a day, a week, and a month after surgery and beyond—form the basis of Project Prakash’s scientific studies. (Participation in the studies is voluntary, and children are offered treatment regardless of whether they participate.) The first significant finding altered the way doctors view the problem of childhood blindness. Previously, many doctors (in India and elsewhere) were convinced that once blind children reached a certain age, around six or seven years, there was no point in treating them. Their brains, it was believed, had lost the ability to learn to process visual information. This idea of a “critical period” has been around since the 1960s, when scientists showed that kittens with their eyes sewn shut from birth to three months of age have greatly reduced neural activity in the brain regions that process vision once their eyes are opened. This effect was not seen in cats deprived of visual input later in life.
However, studies published by Sinha and his colleagues in 2006 and 2009 found that children treated as late as their teens—and in one case, a 29-year-old adult—were still able to see well enough to recognize objects and navigate the world. This does not mean they have perfect vision—many will never have eyesight better than 20/80, even with glasses. “It seems like there is a critical period for development of perfect acuity,” says Sinha. “But for other tasks, they do not seem to have a critical period.” One early patient, Bablu, was treated for cataracts at age 16. Before his surgery, Bablu was shy and lacked confidence, often sitting with his shoulders hunched, says Ostrovsky. Not much changed during the first few months after his surgery, but about 10 months later, when Ostrovsky saw him again, he seemed like a different person.
“He interacted with people in a completely different way, because his vision had improved to the point where it was very useful to him,” says Ostrovsky. “He had moved out of the youth hospital, he could live on his own, he could go shopping on his own for food. You really saw the difference in his demeanor.”
Suma Ganesh, head of pediatric ophthalmology at Dr. Shroff’s Charity Eye Hospital, says that seeing the improvements in Project Prakash patients has made many surgeons more willing to operate on older children. “These children were dependent on others for everything, or were studying in blind schools or not going out of their house,” she says. “There is improvement in functional vision—some children have started going to normal school, some have shifted from Braille to print.”
Once Sinha and his colleagues established that treated children did gain some visual abilities, they could start probing in more detail how those skills develop.
First they looked at a task called visual integration—the ability to pick out objects from a scene. Soon after surgery, patients were able to identify some shapes, such as triangles or squares, when they were side by side but not when they overlapped. Instead of seeing the outline of each shape, the patients saw each fragment of a shape as its own whole. If one of the shapes was put into motion, however, the patients could identify it much more easily. This suggests that motion provides the brain with critical information about what constitutes an object. Over time, between eight and 16 months after surgery, the brain learns that objects that move together also tend to share other features such as color and orientation, which helps it learn to identify stationary objects as well.
Studies have shown that sighted babies also learn to identify objects by how they move, suggesting that visual development in Prakash children may be following the same pattern normally seen in infancy. “If evolution has discovered some effective ways of learning about the world, it would make sense for similar algorithms to be deployed even later on in life,” Sinha says. (It’s still not certain whether that is what’s happening, he says, especially given that a 10-year-old child has far more experience of the world through other senses than a newborn.)
Project Prakash studies also recently helped answer a centuries-old philosophical conundrum. In 1688, the scientist William Molyneux asked whether a blind person who gained the ability to see would be able to identify by sight an object previously known only by touch. In other words, would information from one sense translate to another? Sinha and his colleagues found that their patients could not immediately recognize objects they had previously known by touch, but they acquired that ability within days.
“To finally get an answer to this question, and to have blind children in India provide an answer to a question that the most eminent philosophers in England had wondered about—that was very satisfying,” Sinha says.
The researchers are now studying how the ability to distinguish faces develops, and they are also using functional magnetic resonance imaging (fMRI) to study the brain’s plasticity—that is, how its patterns of activity change as the newly sighted children learn to process what they are seeing. Preliminary results suggest that as the brain takes in new information, cells become specialized to encode different aspects of what the patient is seeing.
Before Project Prakash, large-scale studies of the newly sighted were impossible to conduct, says David Somers, an associate professor of psychology at Boston University. “Historically, there have been very few cases to look at over the past 1,000 years—maybe 20 subjects who had their vision restored later in life were scientifically studied, so it’s hard to draw big conclusions,” he says. “Now, with so many patients, the science is so much richer. What makes Project Prakash so beautiful is the combination of the scientific side with the philanthropic venture where they’re really helping people who just need a very inexpensive procedure that is hard for them to get access to but can dramatically change their quality of life.”
Taking the next step
One of the first children treated through Project Prakash was a 14-year-old boy named Junaid, who came to an eye screening in Delhi in 2005. Junaid suffered from untreated congenital cataracts in both eyes and was attending a school for the blind in Delhi, where he received very little education. His family, which had an income of $45 per month to feed seven children, would not have been able to afford the $350 cataract removal.
After his surgery, Junaid showed a marked improvement in sight and was able to recognize people and objects and get around on his own. In August 2011, he came to the Shroff Hospital to get his glasses repaired and ran into Sinha, who was impressed with how much the boy’s vision had improved but disheartened to learn that he had still been unable to obtain an education. After his surgery, no traditional schools would take on a teenager whose education level would have placed him in first grade, so he was bouncing around Delhi looking for a job. But employers didn’t have much interest in hiring someone with so little education.
“That struck me as a great tragedy, a great disappointment, for a child who I knew was very smart and had great hopes for,” says Sinha. He enlisted students from the Indian Institute of Technology to tutor Junaid for two years. During that time, Project Prakash is also paying him a stipend to help support his family.
Another treated child, eight-year-old Paras, ended up returning to his school for the blind because no regular schools that his parents could afford would take him. “This problem seems to come up for many children,” says Sinha. “Somehow they are unable to be accepted into the mainstream schooling system, and we need to change that.”
Sinha is now making plans to build a Prakash Center that would include a hospital for eye surgery, scientific research facilities, and a school for newly sighted children. Students would be given a “crash course” to prepare them for their age-appropriate grade level, allowing them to enter the regular school system.
Sinha hopes to build the center near the city of Rishikesh, located about 250 kilometers from Delhi in the plains of the Ganges River—one of a cluster of four holy cities that draws millions of pilgrims each year. Sinha envisions that the center will help pay for its charitable efforts by offering eye care to visitors who can afford to pay for it.
Fund-raising to build the new center, which Sinha estimates will cost $16 million, has just begun. Once $1 million has been raised, the project will be able to buy a piece of land, which Sinha believes will help raise additional money. The focus for now is on restoring and studying sight, but ultimately Sinha would like to expand the center to address other childhood disabilities.
Though the center is still in the works, Project Prakash has already had a huge impact on the lives of many children, and that is very gratifying to Sinha. His sense of obligation to do something about the problem of childhood blindness became much more personal five and half years ago, when his son, Darius, was born.
“Since Darius’s birth, I’ve noticed that it feels like a visceral blow to see another child in pain, because you can’t help but see your own child in that situation,” he says. “You ask yourself, what would you want another person to do if your child was in that situation? And that just clarifies all decisions that you might ever have to make, of what’s the right thing to do. Every child that we are able to help, it’s like a personal victory. It’s deeply satisfying at a human level, and then of course the scientific results are a bonus.”