Imagine that you are a professor of neurobiology who, for the past seventeen years, has been lecturing to your students on the conventional wisdom about the brain. Then, quite unexpectedly, you discover through your own experiences, that the conventional wisdom is not so wise. This is exactly what happened to me.
I had been cross-eyed and stereoblind since very early infancy. When I looked with my right eye, my left eye turned in, and when I looked with my left eye, my right eye turned noseward. Although I had three surgeries as a child, I didn't change my visual habits; I still looked with one eye at a time. But, after the surgeries, my eye turns were more subtle so I looked normal - most of the time. I had 20/20 acuity with each eye and assumed that I had "perfect" vision.
It was not until I went to college that I learned that cross-eyed people like me lack stereovision. I didn't see the 3D in 3D movies, and I didn't see the 3D in regular life. My view was much flatter and more contracted than normal, but I didn't know what I was missing. Besides, I saw no point in pining away for stereovision for I had also learned that stereovision develops only during a "critical period" in the first years of life. I would always be stereoblind.
Then at age forty-eight, I consulted a developmental/behavioral optometrist, a special kind of eye doctor who is an expert in binocular vision and visual rehabilitation. Under her guidance, I underwent optometric vision therapy and learned to do something that most six month old infants already know how to do: I learned to point BOTH eyes at the SAME place in space at the SAME time. This required lots of daily practice and vision therapy sessions, and along the way, my brain rewired. I achieved what I and most other scientists had thought impossible: I began to see in stereo depth.
My new view of the world was magical, enchanting, and beyond anything I could have imagined. Tree branches loomed out toward me or grew upward enclosing and capturing palpable volumes of space that I had never seen before. Snow flakes danced around me in 3D. I felt immersed in my three dimensional surroundings. The experience was so overwhelming that I looked for and found other people who had also gained stereovision in adult life. They all said the same thing: their new views were absolutely breathtaking.
Now, what was I going to tell my neurobiology class? For seventeen years, I had lectured about "critical periods" in early visual development - how certain perceptual skills, such as stereovision, had to develop very early or they were lost forever. Yet, twenty-first century, scientific research indicates that the brain is more flexible, more plastic than was once thought. There are scientific explanations for my visual transformation. So I had to rewrite my classroom lectures.
And I wrote a book too: Fixing My Gaze: A Scientist's Journey into Seeing in Three Dimensions. While researching this book, I learned a great deal about vision, spatial perception, neuroplasticity, learning, and rehabilitation, and I will write about all of these topics in this blog.
