Thursday, May 01, 2008

From the Mouth of the Optometrist (Plus, Chicken Brains)

I've been getting a lot of conflicting advice about my glasses: should I be wearing them all the time or only when I need them? Will wearing them prolong the quality of my eyesight, or vice versa? If I don't wear them constantly, will I ever get used to them?

I should have known that my OPTOMETRIST was the person to ask. Here's what he said, for the enlightenment of future generations:

* The reason the world looks strange when I'm wearing the glasses is because of my astigmatism. If this persists, they can reduce the power of the lenses.

* Given my age, my eyesight will not deteriorate any slower whether or not I wear glasses. Likewise, wearing them will not in any way weaken my eyes.

* In order to adjust to the glasses (the distorted world and the feeling of strain) I should wear them pretty much constantly for a week. At the end of this period I can wear them whenever I want to...when I put them on the adjustment should happen much faster, and when I take them off I will still adjust back to not wearing them. This is not a permanent change (see "Chicken Brains," below).

* By wearing them constantly I WILL get used to how sharp and clear the world can be. When I take the glasses off I will probably miss that sharpness.

So I'm in my fourth day of forcible adjustment. Wearing the glasses at work has been a lot of trouble because I need to struggle to focus on things that are close-up...and I spend all day looking at close-up things. I have not been the most efficient and useful worker this week, spending part of my time staring in an unfocused way at the top edge of my computer monitor and wishing that the day would end.


Perceptual psychologists LOVE their prism glasses. By putting these glasses on various creatures at different ages and seeing how they adjust to displacement, they can learn an awful lot about the brain and its wiring.

In one of my classes the professor described an experiment commonly done with chickens. They put glasses on a chicken to displace its vision about twenty degrees, then they watch it try to peck at a seed on the ground. Chickens will continually peck twenty degrees away from the seed, never coming anywhere near the target. They can't adapt.

Most mammals, however, adjust to this displacement eventually through an unconscious mental process. To demonstrate, the professor brought volunteers to the blackboard, made them wear the prism glasses, and asked them to repeatedly and quickly strike out with a piece of chalk while aiming at a spot on the blackboard. I was one of these volunteers and we all reacted the same...the strikes started off far from the target, but gradually reduced the distance until they were bullseyes. Our brains had made an unconscious adjustment, and even though the target still appeared farther to the left than it actually was, our hands could reach it with very little error.

One volunteer, however, was totally unable to hit the correct spot. His errors remained constant. The professor announced to the class that this volunteer had the brain of a chicken, and the nickname "chicken brain" stuck.


Anonymous said...

I have worn glasses for about ten years with slightly stonger prescriptions every two years or so with astigmatism in the mix.

Every time I get new glasses, they seem a bit strange -- but only for the first two or three days. If the strange vision continues beyond a week, you probably need an adjustment.

Also, I am a big believer in the wear the new glasses all the time idea -- your eyes just need to "learn" to use the new glasses.

Muffy St. Bernard said...

So the strangeness returns when your prescription changes? I hadn't thought of that.

Right now -- after four days of wearing them constantly -- my eyes aren't straining as much and the world is slightly more normal. But it's hard to tell, because whenever I wonder to myself "how does the world look?" it always looks strange, probably because I'm concentrating on it.

The plan now is the same as the original plan I had: to wear them for driving and for when I want to appreciate far-off things. Otherwise, though, I don't plan to wear them regularly.

Anonymous said...

If you really have been conscientiously wearing them all the time -- taking them off only for showering and sleeping, things should really look normal by this time.

If you get to six days, and things still look odd, you need to have your prescription adjusted.

Muffy St. Bernard said...

I was only being semi-consistent with the glasses -- wearing them about 80% of the possible times instead of 100% -- so that may be why the strangeness persisted.

Since I'm not planning to wear them to work anymore, I hope my productivity increases. :)

Anonymous said...

Hey, I hope you are doing well. How are you doing with your glasses? Did they work out for you in the end? Or did you have to go back and get a new prescription?

Syd Midnight said...

I come here not as often as I should, and work my way backwards, so sorry for being so late..

I got glasses at age 3 and cannot remember NOT having them. Yeah, when you get a new glasses script, it is a mind fuck, you see things TOO sharp, give it a few days to get used to it.

I can't imagine the problems of being able to not wear glasses or do so..

But yeah, you will see things TOO sharp for a bit, it's annoying but you have to let your eyes get used to that. They will. And in the end, you DO see better.

I wonder what frames Muffy would wear.. that's probably not economically feasible.. but pick a good frame or 2, then use fake frames in your show.

Don't underestimate the power of nice frames.. my sorst mover ever was getting cheap thick "child molestor" frames.. my best was getting thin "John Lennon" frames.