Sue BarrySue Barry

For most of Sue Barry’s life, a snowfall appeared to her as a flat sheet with no depth, and she was merely looking in on it. At the age of 48, all that changed. Tree branches formed arcs with spaces between them, and bathroom faucets jutted out from the sink. Snow, well, let her tell you: 

“I now see the space between the snowflakes. I have a sense of being immersed in the snowfall. It’s not just a new way of seeing; it’s a new way of feeling. I’m part of my surroundings in a way I never was before.”

Barry, 68, now sees in three dimensions. She was born cross-eyed, a condition called strabismus

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She had three surgeries to correct it, and while she no longer looked cross-eyed, she viewed the world with one eye at a time: She saw everything in only two dimensions.

Barry is a retired professor from Mount Holyoke, where she is professor emeritus of biological sciences. She and her husband, Dan, moved to Arlington two years ago to be near their two adult children and their grandchild.

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She is the author of two books, Fixing My Gaze (Basic Books, 2009), in which she recounts how she was able to change her vision, and Coming to Our Senses (Basic Books, 2021), which describes the experiences of two people who recovered sight, in one case, and hearing in another.

Her experience in learning to see in 3D was chronicled in The New Yorker by neurologist Oliver Sacks, and she has been interviewed on “Fresh Air with Terry Gross” and on “Morning Edition” on NPR.

Barry's Ted Talk in Northampton in 2012.  

After a lifetime of seeing in two dimensions, she still marvels at the change in her life. “When I look up at the trees and see branches in three dimensions, arcing out from the tree, it still takes my breath away,” she said.

She talked about the transformation of her vision during a recent phone call.

How was your strabismus noticed, and how was it treated?

My parents noticed I was cross-eyed when I was a very little baby. If I looked at you with my right eye, my left eye turned in, and if I looked you with my left eye, my right eye turned in. I used both eyes but didn’t use them together. My parents asked the doctors what to do about this, and they said I’d probably outgrow it, but I didn't. I had surgeries at ages 2, 3 and 7. I don’t remember the first two surgeries, but I remember the third one very well. I had to lie in bed for two weeks with a patch over one eye. I was in the hospital for three days and then spent two weeks in bed. That’s not done anymore.  

How did this affect your childhood?

My mom said I was a difficult child. My mom was this wonderful, caring, loving person; nevertheless, she told me she went back to work in part to get a break from me. I was temperamental, and would hit my head against the floor. My brother says he remembers I cried all the time. I was really struggling. I was always afraid of going blind because I had had these operations. My very first memory was when I was 2 years old and got my first pair of glasses. I remember sitting on the kitchen steps with these heavy glasses on my head. This was 1956, and glasses were then made of glass, so they were heavy, and I was afraid to turn my head, because I was afraid the glasses would fall off and break.

Did your vision problems interfere with learning?

I had difficulty learning to read, because the two eyes were not looking at the same place on the page at the same time. I was put in a remedial class. Back then, you were rigorously tracked. It was basically my mother who taught me how to read. Every time I expressed an interest in anything, I would find a book in the library on that subject, and we read together all the time. I had a hard time learning how to ride a bicycle, roller-skate -- activity where you had to take in visual information quickly, such as when moving on wheels, was difficult.

Explain how your vision worked

Many eye doctors assumed that if your eyes are misaligned, you’ll look with one eye and suppress vision from the other, and things are OK. They don’t realize the amount of effort involved in seeing that way. Your two eyes are looking in different directions. If you don’t suppress the image from one eye, you will see double. And more than that, you will undergo visual confusion. 

Let’s imagine you are sitting in front of a clock. And let’s say your right eye is pointed at the clock while your left eye, which is turned in, is pointed at a lamp. The central vision of your right eye is seeing the clock, and the central vision of the left eye is seeing the lamp, so you may see the two objects as superimposed in space. That is technically called visual confusion. And so it’s one of the reasons you have to find some way to cope. A common way to cope is to ignore the input from the turned eye so you are looking at the world with one eye.

To do that, glance by glance by glance, takes work. The information from the two eyes is constantly in conflict. So you may get good at suppressing the input from the turned eye, but it’s still taking work to do that.

How did you change your vision?

When I was in my 40s, I was teaching an introductory biology class to about 100 students, and I had a co-teacher who said, “How come you never call on the students in the back of the class?” I said, “What students?''

I realized I never looked in the distance, because when I did, things didn’t stay still; they jittered. When I was driving, the letters on a road sign jittered and didn’t stay still. What I had done unconsciously was limit my vision to a close area. Anything farther than that was effortful to look at, so I didn’t look there.

That’s what motivated me to find an optometrist who could help me. Driving was very difficult, and I was still driving my children around, and it made me very uncomfortable, so I was very determined to find a way to get better.

I understand you found a developmental optometrist. What did she teach you?

The treatment that I had, vision therapy, is provided by only a small subset of eye doctors called developmental or behavioral optometrists

I was lucky there was one in my area, and that was Dr. Theresa Ruggiero in Northampton.

The therapy taught me to point the two eyes at the same point in space at the same time. I had been in the habit of looking with one eye and turning the other eye.

Was it difficult to learn this?

I would practice about a half hour a day and go to vision therapy once a week for 45 minutes. I did that for about a year. It was a lot like learning how to play a musical instrument. To play, you have to practice every day and you have to go for lessons.

Did you suddenly see differently?

The change was gradual, and thank goodness. If I had gone from the way I used to see to now, it would have been overwhelming. First, I began to see large objects, like the steering wheel on my car, floating in front of the dashboard. As I got better, I could see more depth at a farther distance and not just in the very center of my visual field but to the sides. The world just gradually inflated. I remember being in the bathroom at Mount Holyoke, and the faucet was jutting out at me, and I said something about it to a student, ‘Look at that!’ The poor student left the restroom in a hurry.

Had anyone ever said you could change your vision? 

The thought was that if you did not have straight eyes -- eyes that looked at the same space at the same time  during a “critical period” in early childhood -- vision neurons would be monocular (responsive to only one eye). As a result, you couldn’t see in 3D. After this critical period, which in people lasts somewhere between six months and eight years, the brain couldn’t rewire itself in adulthood to create binocular neurons for stereovision. So If you didn’t have stereovision by age 8, you would never have it. I didn’t have stereovision even after my surgeries, because the surgeries didn’t teach me how to look in a different way.

I actually taught about the critical period in my classes at Mount Holyoke and would use my own biography as an example of how well the critical period theory fit reality. 

So you didn’t expect to have 3D vision?

No, when I went to Dr. Ruggiero, I didn’t say I'm coming to get 3D vision.  Instead, I told her that my vision was unstable and I didn’t expect to gain 3D vision. So when I first started to see in 3D, I didn’t believe it. It took me almost two years to convince myself, yes, this is 3D vision. I was hesitant to tell other scientists about it, because I thought they would think me delusional.

Why did you finally decide to write about your experience?

One night in December 2004, I was clearing away the dinner dishes. I thought: 'I have to put my story down in narrative form before I forget it.' I had kept a very detailed vision diary. “Today I was looking at a grape”  -- all the minutiae I had seen. I had that and my memories of growing up without stereovision.

I sat down and started to write and decided I would write it as a letter to [neurologist and writer] Oliver Sacks. I wasn’t thinking of sending it to him. I had met him once eight years before, and he, noting my crossed eyes, asked if I could imagine what it was like to see with two eyes. I told him at the time that I thought I could but now realized that I was completely wrong.  I began my story with his question and completed it nine single-spaced pages later. I showed the story to my husband, and he said that’s a good letter – you should mail it.

I said I wrote it as a diary. He said, no, go ahead and mail it. Before I lost my nerve, I signed my name and put it in the mailbox. Sacks wrote back five days later.

I understand Oliver Sacks wrote about you for The New Yorker and dubbed you “Stereo Sue.” What happened after that?

After he wrote his story in The New Yorker in 2006, I was on NPR and interviewed by Robert Krulwich, and it made it on to “Morning Edition.” Within the first hour or two after that, I had 60 emails in my inbox. I hadn’t even given people my email; they found me through Mount Holyoke. At this point I have received over 1,000 emails from people with strabismus. It made me realize this story really struck a nerve. Oliver Sacks’s piece was wonderful, but it was only 8,000 words and couldn’t describe everything I wanted to say about vision therapy and what strabismus is all about. I wanted to interview other developmental optometrists, interview patients and find other people like me. Oliver Sacks encouraged me along these lines. I wanted a detailed study that was also accessible to people.

Is that how you decided to write your book?

I decided after the reaction to the “Morning Edition” piece that I should write about this. Being a scientist, I could understand the scientific work, and being a teacher of freshmen in college maybe I could explain things in a straightforward way. I really wanted to help other people. That’s what got me started thinking about writing a book. When I told Oliver Sacks about it, he leaned back in his chair and said, “Then Stereo Sue will be my introduction of you to the world.”

Aside from telling your own story, what did you hope to accomplish with your book?

One of the things I really wanted to stress in the book is how much our perception is learned. So many things we take for granted are things we had to learn as tiny infants when we don’t have any memory of learning those things. It’s really kind of amazing; in a large way, babies teach themselves. Think of a baby crawling. It’s not like you got down on the floor to show them. They taught themselves.  These thoughts also led to my second book, Coming to Our Senses, which describes the experiences of two people who gained a new sense in adolescence. 

What did you learn about the brain from your experience?

At the time I wrote Fixing My Gaze, there was a lot of excitement in the neuroscience community that the brain is more plastic than people once thought. My story, as well as the stories in Coming to Our Senses, really contribute to that sort of general feeling that things aren’t so cut and dry. Maybe this idea of a critical period is not the case. Scientists might now call it a sensitive period. A young brain is more adaptable than an older brain, but it doesn’t mean an older brain can’t learn.

For more about Barry, see her website,

This news feature by Marjorie Howard was published Saturday, May 28, 2022.