The Boy Who Learned to See—and What He Teaches Us About Vision

By Susan R. Barry

June 18, 2021 11:04 am ET

At age 15, Liam McCoy underwent surgery to allow him to see clearly for the first time. But repairing his eyes was easier than retraining his brain.



To ask a blind person to acquire the sense of sight after childhood is to ask them to reshape their identity. They may have functioned quite independently when blind but now find themselves as vulnerable as a young child. With their new sight, they can see but cannot recognize a flight of stairs or a loved one’s face. Bombarded by visual stimuli they don’t understand, many who gain sight in adulthood become despondent, reject their vision or even lose the will to live.

At first blush, vision seems a purely mechanical process. Photons hit the light-sensing pigments in the retina of the eye, triggering a cascade of electrical and chemical events that send signals to the brain about light, color and motion. Yet these events tell only part of the story. Even if we all possessed identical sensory structures, we would each perceive a different and very personal version of the world, a version built upon our experiences, needs and desires.

‘Perception is not something that happens to us, or in us. It is something we do.’— Alva Noë, philosopher

As the philosopher Alva Noë has written, “Perception is not something that happens to us, or in us. It is something we do.” We move our body, head and eyes to look and listen, to take in information about the world. Since we direct what we see, developing vision as an adult is an intensely active process. A new pair of eyes won’t lead to vision unless the owner of those new eyes pays attention to what he is sensing and figures out its meaning.

I first met Liam McCoy in 2010, when he was 20, five years after he had undergone sight-restoration surgeries. The operations added a powerful artificial lens to each eye without removing the eye’s natural one. I was introduced to Liam through his surgeon, Dr. Lawrence Tychsen, a professor of ophthalmology at Washington University in St. Louis. Dr. T. (as Liam calls him) cares for children with neurological impairments, often so severe that other doctors consider them too difficult to evaluate and treat.

From the moment Liam was born, it was obvious that there was something different about him. His hair was metallic silver, and blood vessels were plainly visible through his very light-colored skin. “Oh my God!” the nurse exclaimed as she rushed from the delivery room. Moments later, she returned with the doctor, who took one look at the newborn and hurried out too. When the doctor returned, Cindy, Liam’s mother, now deeply concerned, asked what was wrong. “Oh, he’s a towhead; he’s a cotton-top,” the doctor responded.

Liam wasn’t completely blind, but his zone of clear vision extended only 3 inches from his nose.

From the start, Cindy suspected that her child had albinism, a diagnosis that was confirmed when he was 17 months old. Albinism, or a lack of the pigment melanin in the hair, eyes and skin, is a rare condition, affecting only one in 17,000 people. Since Liam’s eyes lacked melanin, he was extremely sensitive to bright light. He also had nystagmus, an involuntary oscillating movement of the eyes. As a child, Liam told me, he could not willingly look at anything.

Albinism wasn’t the only source of Liam’s poor vision. He was also extremely nearsighted. Dr. Tychsen explained that Liam was living in “a cocoon of visual blur.” He wasn’t completely blind, but his zone of clear vision extended only 3 inches from his nose. As a result, his visual development was severely disrupted, and the surgeries he underwent at age 15 were only the beginning of his vision restoration.

Liam had surgery on one eye in December 2005. Surgery on the second eye followed five weeks later. There was no sudden “I can see!” moment. Liam’s eyesight was supposed to stabilize in six weeks; instead, it took months. But when it did, his visual acuity had vastly improved. Before surgery his acuity was 20/2000 without glasses and 20/250 with the thickest lenses. Six months later, with no glasses, he was seeing 20/50. His albinism prevented him from seeing 20/20.

Nine months after the second surgery, one of the lenses moved out of position, causing Liam to experience double vision. The lens was replaced, and this time the improvement in acuity was immediate. The gains in acuity after the first two surgeries may have occurred gradually because it took the brain some time to process all the new information that the eyes could now provide. Not only did his acuity improve tremendously, but his nystagmus was reduced. Reds no longer faded for Liam as the day wore on (though blue remained his favorite color). His binocular vision improved, as did his depth perception, albeit slowly.

But the improvements were discombobulating. Surgery plunged Liam into a world of sharp lines and edges. He now saw lines wherever there were changes in color, light or texture; where one object ended and another began; where an object in front occluded an object behind; and where a shadow was cast on a surface. While we all see lines at the boundaries of objects or shadows, we know where these lines belong. We recognize an object immediately—all of its parts combine together, instantly and effortlessly, into a single unit. But after a childhood of near-blindness, Liam did not recognize the lines as boundaries of known objects. Instead, he saw a tangled, fragmented world.

For most of us, vision feels so seamless because it results from a combination of “bottom-up” and “top-down” processing. “Bottom-up” implies constructing the visual world from the smallest pieces of visual information. These details are, in large part, handled by neurons in lower areas of the visual cortex. But we cannot think of these neurons as responding only to the “bottom-up” stimuli that our eyes provide. Their activity is modified by input coming from their neighbors as well as from other regions of the brain.

Prior experience, past associations and our level of attention all influence the firing of lower-area neurons, a process that depends on feedback from higher visual areas and is therefore called “top-down.” Since we all have different experiences, needs and desires, “top-down” influences differ from person to person. We all see the world through our own perceptual lens.

After his surgeries, Liam’s eyes provided his neurons with the input they had long been waiting for. But he lacked the visual experience of seeing beyond a few inches, so he had not yet developed the “top-down” processing that organizes these local details into coherent objects and landscapes. As a result, he had to rely heavily on “bottom-up” processing and consciously piece together the visual world from its parts.

“Up close,” Liam wrote, “things are more like objects than visual chaos, but there is a definite difference when I see something further away. Those objects have no meaning, and I struggle to tell if a bar of color is the front of a truck or side of a bus or roof of a building. If people even stand slightly further away and talk to me or say hi from down the hall, it has a very different feeling, and it doesn’t seem as real.”

In his memoir “Second Sight,” the historian Robert Hine described his experience of going blind in middle age and recovering vision 15 years later. He wrote of the blind participating in the world of the sighted: “Whether or not senses like hearing and touch grow sharper, the ability to imagine must intensify, and it is there that the blind can outshine the seeing.”

Throughout childhood, Liam lived and went to school with sighted people; he had to infer what others saw, requiring great powers of analysis and imagination. After his surgeries, he used these same skills to decipher what he could now see. As he began to recognize individual objects among the confusion of lines, he most likely developed new networks in higher object-recognition areas of the brain. Neuronal connections, like ruts in the road, deepen with use. With each day, Liam’s vision became more “top-down,” providing more meaning to his visual world.

Although he can recognize many more objects today than he could right after his surgeries, Liam still struggles to recognize faces. Prior to receiving his intraocular lenses, he couldn’t see details on another person’s face; their nose and mouth were just a blur. Right after his first surgery, Liam was disgusted when he saw the way that his mother’s mouth moved when she talked. He knew that his mouth moved when he spoke, but it was a revolting shock to see the details of the red lips and tongue in others.

Indeed, without a holistic sense of a face, it was impossible for Liam to recognize people from moment to moment. Their faces transformed entirely when they changed expression or talked. Problems with recognizing faces and facial expressions are very common among people with long-term blindness who gain sight as adults. Even people blinded by cataracts from birth whose sight is restored within the first year show some deficits in face recognition.

Though we are not born with an innate ability to recognize household or most natural objects, we may be born with a rudimentary face-detecting skill. Infants just nine minutes old exhibit a preference for looking at a human face. This remarkable fact was discovered during an experiment in which different pictures were moved across a newborn’s field of view. When a face pattern (an oval for the head, enclosing shapes that looked like eyes, a nose and a mouth) was waved in front of the baby, the child would turn his or her head and eyes to follow the pattern. But if the features were all mixed up so that the pattern no longer resembled a face, the infant did not follow the pattern as reliably or for as long.

One area of the brain that is particularly active when we look at faces is called the fusiform face area. Intriguingly, this same area “lights up” when expert chess players look at a chess board. Why would an area of the brain important for the recognition of faces be activated in chess experts when they view a chess game?

To recognize a face, we need to see more than the eyes, nose and mouth. We must analyze the spatial relationships among all of these features. Similarly, an understanding of the spatial relationships among game pieces is crucial for winning at chess. The fusiform face area is good at recognizing global spatial patterns. Circuitry present at birth or soon after and an infant’s preference for looking at faces likely bias the fusiform face area to become a face recognition area. That role is bolstered further by our lifelong experience with viewing faces and the importance of face recognition in everyday life.

Liam assigns the way people look to broad categories based on the features that he sees best—short or long hair, glasses or no glasses. One of the first people he recognized with his new vision was his college professor, Joe. Here’s what Liam wrote in an email to Dr. Tychsen in 2012: “Joe has black and gray hair and a mustache, and I recognize hair best instead of faces. Especially mixed color hair and facial hair (even though when I look away I can’t definitely describe it). So when I recognized him automatically on campus outside of class, I had to go tell him how special it was and that he was the first person I recognized like that.”

When I first met Liam, he didn’t look directly at me, hardly showed any expression on his own face and spoke quietly. When I see him now, his face breaks into a big smile.

With facial expressions, too, Liam ran into problems. Eight years after his surgeries, I showed him a set of cartoon faces displaying all sorts of emotions, including happy, surprised, skeptical, disapproving, confused, fearful and sad. He told me that the only expressions he really understands are happy and sad. But he may be picking up more information from faces than he is aware of. His own appearance has changed. When I first met Liam, he didn’t look directly at me, hardly showed any expression on his own face and spoke quietly. He has since become more animated, and when I see him now, his face breaks into a big smile.

A person’s ability to adapt and learn involves more than structural changes at synapses. Every time we witness performers at a circus, symphony, ballet or professional ballgame, we are seeing the results of neuronal plasticity. While these performers may possess natural gifts, they wouldn’t have achieved the elite level without a singular focus and years of intense practice. Neuronal plasticity and learning require active training. In his book “Rebuilt,” about learning to hear with a cochlear implant, technology theorist Michael Chorost wrote that he had to become an “athlete of perception.” Only by tirelessly experimenting and practicing with his new sense, only by becoming an athlete of perception, could Liam begin to understand what he sees.

Liam worked so hard on his new vision that Cindy, his mother, sometimes wondered whether he should have undergone the sight-restoration surgeries at all. Despite these difficulties, there were times when watching Liam learn to see had all the magic of watching a very young child discover the world. Since vision for Liam is such hard work, he rarely describes what he sees as beautiful, but Cindy remembers one morning when she and Liam were up with the sun and he saw dew for the first time. “It’s like Christmas lights on the grass,” he said.

Dr. Barry is a professor emeritus of biology and neuroscience at Mount Holyoke College. This essay is adapted from her new book, “Coming to Our Senses: A Boy Who Learned to See, a Girl Who Learned to Hear, and How We All Discover the World,” published this month by Basic Books.


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