I was 20 years old before I learned that I did not see the world like everyone else.
I had been cross-eyed as a baby, but three childhood surgeries made my eyes look straight. Because my eyes looked normal, I assumed I saw normally. But in fact, I was "stereoblind," unable to see in three dimensions.
That means I could not see the volumes of space between objects. Instead, things in depth appeared piled one on top of another, making me feel nervous and confused in cluttered environments.
As a child, I didn't understand why my friends were so entertained when they looked through a View-Master. I didn't see Disney characters or Superman popping out at me. All I saw was a flat image.
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When I got older, my gaze -- particularly at a distance -- was jittery, making it difficult to read signs while driving. I was always disoriented and easily lost.
The biggest effect of my vision was on my performance in school. I had trouble learning to read and did poorly on standardized tests. These problems were blamed not on my vision but on a lack of intelligence, and I was put in a class with problem children.
That was in the early 1960s, but the situation hasn't greatly improved. Children are still not routinely tested for binocular vision deficits because the standard school vision exam (reading the eye chart with one eye at a time) doesn't screen for defects in eye coordination or stereovision. As a result, many children with vision problems might be labeled learning disabled or, if they misbehave in frustration, diagnosed with attention-deficit hyperactivity disorder.
Despite my visual shortcomings, when my husband and I took our children to Disney World 16 years ago, I insisted that we see the 3-D movies.
As my kids watched gigantic insects fly off the screen toward us, they screamed and retreated to the safety of my lap. They were thrilled, and so was I. Although the bugs did not pop off the screen at me, I knew that my children's view of the world was much more stable and depth-filled than mine, and that they were less likely to encounter the problems that I had faced in school.
Then, at age 48, I consulted a developmental optometrist who used a vision therapy program to teach me how to coordinate my eyes and see in stereo. With my new stereovision, I learned to play tennis and could drive with confidence and without fatigue.
Most surprisingly, my view of the world changed in ways I couldn't have imagined.
Ordinary objects looked extraordinary. Sink faucets popped out at me; light fixtures appeared to float in midair; tree limbs reached out toward me as I felt immersed myself in a three-dimensional world.
So it was with great anticipation that I recently attended a showing of "Up," the new 3-D Disney-Pixar film.mo
When I put on the Polaroid glasses, the film scenery bloomed into three dimensions. Balloons floated off the screen and clouds receded far into the distance. Even the characters' noses seemed solid and palpable.
Perhaps 3-D movies have more to offer than pure entertainment.
With the growing number of 3-D films for children, perhaps more parents will spot visual deficits, and seek the treatment that can improve a child's vision -- and transform a child's life.
Barry is a professor of neurobiology at Mount Holyoke College and author of "Fixing My Gaze: A Scientist's Journey Into Seeing in Three Dimensions."
LOS ANGELES TIMES