I’ve noticed a visual phenomenon that I’d like to understand.
For a couple of years now, I’ve been unable to eat carbs during the day without getting a serious case of the nods. I generally avoid them at lunch, but every once in a while I toss caution to the wind, as I did today, and have a hefty lunch, resigned to an afternoon of not really knowing where I am or what I’m doing. I attribute this to blood sugar swings, but that’s not the point here, and I’m usually wrong with my self diagnoses anyway.
So, one effect of what I tend to think of as self-administered nutricide is an involuntary crossing of my eyes*****. What I’ve noticed is that when I’m fighting with my eyeballs, and trying to keep them from crossing, there’s a point where I presume my eyes are right at the threshhold of losing their grip on the integrated binocular single picture view, i.e., beginning to cross, when my distance visual acuity is actually heightened just a bit.
What’s happening to improve my distance vision a little bit there?
One of my co-workers offered, with his usual aplomb and complete lack of hesitation, the explanation that this is a manifestation of the pinhole effect, with which I am familiar, but a.) he’s an excellent bullshitter (for which I value him) and b.) the explanation did not make sense to me. As I understand it, for that to come into play, my pupils would have to constrict and I’ve gone to the restroom when battling the nods to check - doesn’t appear to be the case.
*****[sub]I 've asked here before and never received a very good answer about what’s happening to make the eyeballs try to cross. While not my main question tonight, if you have some input, fire away.[/sub]
Are you normally somewhat shortsighted? If so it’s probably caused by a contraction of all the muscle sin the eyeball. There’s one muscle that can actually distort the shape of the eyeball and overcome the effect of shortsightedness to a large degree. This muscles, and the fact that it’s being constantly exercised, has been used to explain why outdoors type people are rarely shortsighted until very late in life while indoors types are often shortsighted by the time they hit there teens. It sounds like all the muscles in your eyes are spasming for some reason. It’s possible that it’s also affecting that one, which isn’t normally able to be consciously contracted, and as a result your distance vision is improving as the eyeball distorts.
If your eyes are shaking back and forth, that’s nystagmus. Nystagmus can occur when neurotransmitters are depleted so it may also be caused by certain nutrient deficiencies. It’s possible that you’re experiencing nystagmus even if you don’t notice your eyes moving quickly right and left – you’d need to have someone look at your eyes to be sure. It’s also possible that what you’re experiencing isn’t nystagmus at all.
Since this phenomenon seems to be related to carbohydrates and thus to blood sugar and insulin levels, I would strongly recommend discussing what’s happening with a doctor, if you haven’t already. Not being able to tolerate carbohydrates during the day could be a symptom of an underlying problem with carbohydrate metabolism or blood sugar regulation.
Not the most reliable reference, but the best I can find:
Those who regularly focus their eyes over longer distances, such as sailors and mountaineers, are apparently less likely to become myopic. It seems likely that the muscles on either side of the eye can be trained to contract the eye, thus overcoming short-sightedness.