Well, there's something you don't see every day.

Wednesday, August 05, 2009 Filed in: My Life, Techniques & Training, General gun stuff

Did you know your eye dominance can be changed? I didn't!

I recently had a problem with shots hitting several inches off my point of aim (at only 5 yards.) That's odd, I thought, it's as if I'm seeing out of my left eye. But that's impossible - I'm right eye dominant.

For some reason I did a quick dominance test, and I was shocked that it showed I was left-eye dominant! I must have done it wrong, I thought; I did the test again, and it showed the expected right eye dominance. Whew! One more time, just to be sure - darn it anyway, it came up left again. And again.

That's odd. Dominance, as I've always understood the mechanism, is neurological, not optical. Your brain simply prefers the vision from one eye or the other, and it appears to be hardwired from birth. I've always thought it to be unchanging, as most people do, yet mine had definitely changed.

Guess what? Turns out it's not as immutable as I'd believed. According to my ophthalmologist, who I called the next morning, eye dominance spontaneously changes only in a very, very small percentage of adults - usually as a symptom of an underlying neurological disorder.

Neurological disorder? Doesn't that mean...tumor?? YIKES!

As it happens, I'd had a complete physical (including a thorough eye exam by this doctor) just a couple of months ago. I had no other symptoms, and he reassured me that lack of symptoms and my recent positive tests made me an unlikely patient for surgery.

As it happens, he said, eye dominance can be trained away. The usual trick is to wear glasses with some Scotch-type tape on the lens of the dominant eye. The out-of-focus image forces the brain to use the other eye, and in time becomes used to the arrangement - thus changing the dominance.

But, I protested, I haven't put any tape on my glas....oh, wait.

For years I've worn a jeweler's loupe over my right eye. When I'm working, I swing it down so I can look through it and back up when I no longer need it. It's a hassle to swing it in and out of my vision all the time and get it perfectly aligned again, so for the last year I've just sort of looked around it instead of flipping it up. I use my left eye for distance vision, and the right when I need to do closeup work.

What I normally see in my right eye, then, is...an out-of-focus image. It's the same as tape on the lenses, and by doing that I've unintentionally trained away my right eye dominance! At this moment I'm part of the small number of people who have no strongly dominant eye. If I continued using the loupe in that manner I'd end up strongly cross-dominant.

I immediately swapped loupe positions to force my brain to accept the right eye again. It's been a month or so, and I'm already seeing results. Once I'm back to my normal, strong right eye dominance I'll swap my beloved loupe for a binocular magnifier.

Trouble is, I hate those things! Decisions, decisions...

-=[ Grant ]=-
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