I cried the first time I held a Nintendo 3DS. The experience was a revelation that I'll not soon forget, and even if everyone stopped making games for it tomorrow, my blue 3DS XL is not going anywhere. That little machine is a window into a part of human experience that most people take for granted, but which is otherwise inaccessible to me.

124 Millimeters of Depth

I am mostly stereoblind. Stereoblindness is a blanket term for any condition that prevents a person from perceiving depth using binocular vision.

Depending on whom you ask, it affects somewhere between 3 and 15 percent of the world's population, which creates an interesting demographic hurdle for the 3D television industry. Some people are stereoblind because their vision in one eye is severely impaired, others because their brains are unable to coalesce images from both eyes into a three-dimensional result.

I'm very slightly cross-eyed. Not enough for anyone else to notice, but enough that my lines of sight intersect about 10-12 inches in front of my face and continue in divergent directions.

Basically, I have double vision all the time.

Childhood eye therapy and surgery (not LASIK—I had sutures on my left eyeball) helped a bit, but most of the time I just use one eye and ignore the other. Being stereoblind isn't that much of a handicap; I can't see Magic Eye images, and 3D movies are just 2D movies with lousy contrast, but that's about it.

I say I'm "mostly" stereoblind because despite my eyes' poor grasp of trigonometry, the optical center of my brain seems to work just fine. I discovered this the first time I held a 3DS and played Pilotwings Resort. To be perfectly honest, I really didn't expect much from the console. But clever readers have already noticed that my sight lines meet at just the right distance for holding a 3DS.

After playing with the depth slider off for a few minutes, I slid it up out of sheer curiosity and saw something I had never seen in my life: a third dimension.

This is how other people see the world all the time.

Not only was I "seeing into the screen" the way so many others feel when playing a 3DS for the first time, I was seeing in a direction that had previously been literally invisible to me.

It's difficult to come up with a metaphor. Maybe it's what Gomez saw the first time he spun the world in Fez. Maybe you can remember the first time you lay on the grass at night, looked up at the stars, and realized you weren't looking up at all, because there is no "up", and you were suddenly aware of being attached to the surface of a tiny sphere rolling through a vast emptiness. Or perhaps you once looked at an Escher woodcut long enough for the positive and negative space to switch places. I suppose any analogy would be imperfect; I was seeing a new piece of everyday reality.

As silly as it may seem to get an existential epiphany out of a $200 plastic gadget, the apparent solidity of the tiny simulacra on that screen made them seem almost more "real" than the world around me, which looked suddenly flat by comparison. It didn't matter that they had three-digit polygon counts and textures that must have topped out at 512x512. I had never before perceived things as having volume, only a sort of surface area in terms of how much of my vision they took up. It was intoxicating. It was a glimpse into something that I immediately realized was part of everyone else's normal experience. This is how other people see the world all the time. There's nothing magical about the perception of depth.

I had never known it was possible for reality to look this way—for things to look as solid as theyfeel.

Yet there I was, holding this little chunk of plastic and silicon in my hands, tears streaming down my face because I had never known it was possible for reality to look this way—for things to look as solid as they feel. I couldn't look away. I got a 3DS of my own the next day, and later replaced it with an XL. I revisited Hyrule in Ocarina of Time 3D, stopping and staring at every piece of architecture. I still spend more time running aimlessly through Super Mario 3D Land's gorgeous environments than I do trying to beat the game.

Wouldn't anyone, if it were the only place where things had volume?

Sometimes I despair. Sometimes it's hard to face the possibility of never being able to perceive mountains or forests or ancient ruins or modern cities or my parents or my fiancée with such depth as I can see Link opening a treasure chest inside an illuminated 4.88-inch rectangle. But ultimately, I'm incredibly lucky to have only this minor affliction to contend with.