Wednesday, November 10, 2010

Depth Perception

After I wrote it, I realized that it was a lie. Last week I said that I hadn't finished a single non-school related book since I got here. That's not actually true. My first month here I finished this guy: 

Fixing My Gaze: A Scientist's Journey Into Seeing in Three Dimensions by Susan R. Barry 

I had been wanting to read it for a while and remembered at the last minute to pick up a copy before I left Texas. It was a little more scientific than I bargained for, but it was fascinating. 

It might seem like an odd book to read unless you know that (drumroll please) I am stereoblind

Yep. You've probably heard me talk about it endlessly or not at all. Basically it means that your two eyes don't necessarily compute and combine the slight differences they see resulting in a lack of depth perception. Now before you start lining up cups and asking me if the blue one or the red one is in front, I can do that kind of stuff. No need to take away my driver's license. It's not that I can't see that something is in front of something else. It's just that I can't see the space between things. 

I had been trying to tell people about this for years. The only reason I knew that I didn't have depth perception was because every once in a while I did. Occasionally, when walking home or dashing around campus, especially if it was a sunny day, I would notice the leaves on the trees were really defined. All of a sudden it is like stepping into a pop up book. It always seemed like magic. I remember the fist time I saw why it's called looking through the looking glass. I had always seen myself flat on the plane of the mirror. 

I would usually confuse people by saying, Oh look. I have depth perception today! For a while I tried to explain it by saying that I basically saw the world like a regular movie, while other people saw the world like a 3D movie (which probably helps to explain why I never really understood 3D movies). After reading the book though, this doesn't really help either: apparently the eyes of people with stereovision (those with depth perception and 3D vision) actually create 3D when they watch regular films as well. 

Anyway, I believe it was the crunch time of the Spring semester that led me to procrastinate by researching my vision online (I think it was also after I had tried to explain it to a friend...who told me that was not how normal people saw). I was surprised to find out that other people had the same experience, and found a review of this book online. 

As it turns out, stereoblindness is not that uncommon. Some people who are cross-eyed or have a lazy eye (or did as a child) or even just don't have eyes that are perfectly aligned have the same problem. Sometimes it is just because one eye is much stronger than the other. It's kind of funny because I always said that I felt like my center of gravity was over to one side of my body--I am constantly ramming my shoulders into door panes and walls. Turns out, it might just be that my eyes use images from one eye predominately. 

The fun part of the book is that there are lots of little exercises to help you practice your vision. Sitting around in airports and offices I am sure there were plenty of people confused by my squinting and focusing. I had already figured out that if I tried really hard I could conjure up a bit of depth perception. If I close my left eye, focus the right one well, and then open the left one, sometimes I can get the images to merge. When I am just sitting around, I try to practice. This came in handy when I drove back and forth between Abilene and FW two dozen times this summer (watching the hawks flying through the air is fascinating when you have depth perception!) or when I got bored in class (I would try to make a desk, or a pencil pop out,  or even sometimes I would just stare at the professor and try to see his nose in 3D. Ha!) (Apologies to any professors reading, I'm sure it wasn't your class!)

All of this to say that when I was little and wondered if what saw as blue, was really what you saw as blue, or if we all saw things a bit differently, might have a bit of truth in it after all. (Cue some postmodern philosophy and situated hermeneutics!)

So now you know. 

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