Aug. 25, 2003 -- Michael May had been totally blind for four decades when he underwent the experimental operation that "restored" his sight three and a half years ago. While the surgery was a success, May, like others who have regained their vision after decades of blindness, still sees the world very differently from most people.
"I don't recognize faces at all, so I focus on hair length and color or body shape or height to figure out who someone is when I see them," he tells WebMD. "If I meet someone new I might memorize what they are wearing that day -- the color of their clothing or something else distinctive -- so that I can recognize them later."
May became blind at the age of 3 after losing one eye and was blinded in the other due to chemical and heat damage to his cornea. After one unsuccessful cornea transplant, May underwent a stem cell transplant in his right eye.
Imaging Issues in the Brain
May's current sight problems have little to do with his eyes, and everything to do with his brain. Although there are only a handful of cases like his, it is becoming clear that people who regain their sight after long-term blindness have more problems adapting to the visual world than those who lose and regain their sight later in life.
Now new research, which used magnetic resonance imaging (MRI) to track what is going on in May's brain, is helping to explain why. Researcher Ione Fine, PhD, and colleagues at the University of San Diego began their studies with May five months after his surgery, and the results of their research are published in the September issue of the journal Nature Neuroscience.
While May is able to detect both motion and color, he has a difficult time identifying objects and has the most problems recognizing faces and facial expressions. The MRI showed that the area of the brain that processes motion functions normally in May, but the area that processes form functions very poorly or not at all, Fine tells WebMD.
In tests conducted two years after his surgery, May had no difficulty recognizing simple shapes such as a square or circle. But he could identify only 25% of common objects that were presented to him, and he was able to tell whether an unfamiliar face was male or female only 70% of the time.
Images of Motion vs. Images of Form
"Motion processing develops very early in babies, and it does not seem to be very plastic," Fine says. "Mike showed that you can switch the light out on motion for 40 years and when you switch the light back on nothing has changed. But form processing appears much more complicated. It seems to be more reliant on experiences later in life."
Fine and colleagues suggest that a person's ability to distinguish complex forms develops later in life, and therefore remains virtually undeveloped in people like May who lose their sight at an early age. They further speculate that this late development occurs because people need to process and recognize new objects throughout their lives.
'Catalog of Visual Clues' Builds Daily
May acknowledges that adapting to his new sight has been a challenge, but he is still glad he had the surgery. A highly successful businessman and accomplished athlete who won six international medals for downhill skiing before regaining his sight, May says he thought long and hard before deciding to have the procedure.
"It took me about six months to decide to do it," he tells WebMD. "There were a lot of reasons not to have it, but I enjoy challenges and I figured I could deal with this one."
He says that for him "learning" to see is similar to the experience of learning a second language. Only instead of new words he learns new visual clues to help him process what his eyes see.
"My catalog of visual clues is building daily. My visual acuity isn't changing, but I am now able to recognize things much faster because of this visual catalog. An image that might have taken me 10 seconds to figure out at the beginning of this road now may take two."
For some time after the operation, May closed his eyes while skiing because the visual images gave him the sense that he was about to hit something on the slopes. He says he still has that sensation, but is slowly learning to ignore it.
"The difference between today and two years ago is that I can better guess at what I am seeing," he says. "What is the same is that I am still guessing."