Gaining depth perception

Monday, April 29, 2024

In 2017, the way I see the world changed, literally. For the first time in my life, I had nearly full depth perception.

When I was a kid, I was always the one who was bad at ball sports. Not for lack of trying, either. I'd run after a ball to catch it, only to be off by a few feet. I'd whiff when hitting a softball pitch. And I quit indoor soccer after taking a third ball to the face, because I didn't realize it was coming straight for me. Even with running, I'd trip, and I ran my bike into mailboxes more times than I care to remember. I'm deeply sorry to the neighbors whose mailboxes I knocked over; I wasn't a vandal, I just couldn't see how close I was to them.

All my life, I thought it was because I was clumsy or just bad at sports. I leaned into endurance athletics, because I knew that I could run and ride a bike, and those didn't require as much hand-eye coordination, which I was crucially lacking.

In 2017, we moved to a small Pennsylvania college town, and I went through the usual pain of finding a new eye doctor. We picked the closest one who was accepting new patients, because it was convenient. It was a fortuitous choice. My wife and I got appointments at the same time and went in together. She went first and had a perfectly normal eye exam. Then he started on me.

He asked me a question no eye doctor ever had before: "Do you have trouble catching a ball?" He was able to list off a few other things I had trouble with, like tracking a line of text or tripping. Then he told me that I seem to have a slight lazy eye. One eye points directly at what I'm looking at, while the other points slightly away from it. That interferes with depth perception, and the brain learns it should just ignore one of the conflicting signals. To confirm this, and demonstrate it to me, he gave me a depth perception test.

I donned what looked like the glasses for a 3D movie, and he placed a card in front of me with nine different figures. Each figure had four dots, and one of them should pop out from the others at varying depths. I got the first two easily, then struggled a lot with the third and basically guessed. Everything else looked completely flat. My depth perception was very impaired.

I really did not believe that the test worked at first, that anyone could see anything on those other six figures. We had my wife do it, too, and she effortlessly breezed through all nine levels of it. I was astonished. I thought I had depth perception, and I did not.

As a fix, he wrote my glasses prescription to include prism in the lenses. He measured the difference in where my eyes point, so the appropriate prism will then correct it by shifting one of my eyes to point at the same spot as my other eye. I ordered my new glasses—my wife's prescription had not changed, as it never does—and we went home.

Three weeks later, my new glasses were in. I drove myself in to pick them up, which was probably a mistake. But I couldn't anticipate the profound experience and shift I was about to have.

He grinned when he presented the closed glasses case to me. "Try them on." I opened the case nervously and put them on and then my eyes... Both eyes were looking at the same place. It was bizarre, like I had truly stepped into a 3D movie, but deeper and surrounding me. This is how people experience the world? Every day, their whole lives? "Anything look different?" he asked me with a grin. Holy...

I paid for the glasses and left, telling myself that I am coming back to this eye doctor as long as he's working. He gave me something I hadn't had for my entire life, something I never knew I was missing. On the drive home, I was a little distracted, but okay. I got home safely.

Once I was home, the rest of the workday was a write-off. I was deeply distracted by the very world around me. There's this one branch on this one tree outside my home office window. I had never noticed it before, but now I couldn't ignore it. If you don't have depth perception, it blends into the tree. If you do have depth perception, you can see it jutting out of the rest of the branches toward you.

I spent half an hour covering one eye. The branch pops in. Uncovering the eye. The branch pops out. Cover, pops in. Uncover, pops out. I excitedly told my wife and asked her to try it. No profound difference for her, because the depth information is so wired in that her brain plausibly filled in what wasn't there and wouldn't forget the depth information the moment one eye closed.

This continued for weeks, months afterwards. When we would go for walks, I got distracted by street signs and trees and power lines and all these things that were newly in three dimensions.

The first day I had my glasses, I was first distracted and then in a lot of pain. I got my first migraine headache. After I got my glasses and my brain started to get the expected input from both eyes, it did give me depth information but it had to rewire to handle that. This resulted in a migraine for about a day.

Each pair of glasses I've gotten since then, if my prescription changes, I get a migraine unless I take migraine medication ahead of time. Since these are predictably timed, I've been fortunate to be able to treat them and largely prevent them.

The depth information integrates into my vision in what seems to be an atypical way. When I see something that's particularly standing out from its background, I perceive it as being closer and I also see a subtle shimmer on it. It's sort of like the shimmer that some video games use to mark objects that you can interact with. It's like my brain decided that this extra layer of information has to be visually represented somewhere.

Some people with lazy eyes get depth perception when they have it corrected, and some don't. I'm one of the fortunate ones who regained almost all depth perception from a pair of glasses. I can now snatch a bal lout of the air without reliably smacking it across the room instead. I trip less when running. Driving is less stressful, and even enjoyable now.

Getting depth perception as an adult has been a profound experience. I didn't realize I was different in any way. I thought that when people said "depth perception", they meant what I did: looking at something and consciously estimating how far away it is. No, most people look at something and just... perceive how far away it is. I've gotten to experience both. I've gotten to experience a lack of a sense and the restoration of it.

This experience has been mirrored in other aspects of my life, where I thought how I experience the world is typical and mirrored by everyone else. It has resulted in revelations about gender and neurodivergence. And it has literally changed how I see the world.

If glasses aren't a truly wondrous thing, then what is?

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