On Feb 28, 10:51*am, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
"Stormin Mormon" fired this volley
:

Do glasses change their focusss over the years? Does the focuss
change, if glasses are in storage?

No, Stormy, not unless they're plastic, and you get them _really_ hot...
and then they "warp"; they don't change focus 'gracefully'.

There are a lot of vision defects besides gross focus that might be at
play. *You might have a very minor astigmatism. *You may have a slight
clouding of the vitreous humor or the onset of cataracts. *You might have
dried out corneae that makes looking at things like looking through
crinkled cellophane. *You might have slight retinal damage from some
bright light or UV incident in the past.

You may also just be a victim of the fact that the eye itself changes
focus slightly during the day, and from times of good hydration to
dehydration.

The humors of the eye are 99.9% water. *Reduce the water in your body,
and you change the concentration of water vs. proteins in the humors.
They change pressure, volume, transparency... *and you "see" it as
glasses that aren't "strong enough".

I've found that most eye tests end up recommending a lens that is just a
bit too 'strong'. *When the image you see goes from clear to SHARP and
more contrasty than before, the correction is too strong. *That puts a
burden on the lens muscles. *Whatever loss of flexibility you have in the
lens from age is then over-taxing those muscles even harder. *They get
fatigued, and you "lose focus" both optically and mentally.

I go from doing long-range work with fireworks to close-up machining, to
CAD, to reading. *The only solution I've found that handles all the tasks
well is a pair of glasses for each situation.

LLoyd



I agree with all of what you said here (except the "focus" part [see
my other reply]). I would be very suspicious, however, of an
optometrist who did not check for all of those conditions. They should
all be discoverable during a routine examination. I can't imagine an
"eye test" without checking for astigmatism. If the examiner is only
doing a simple refraction test (is this better than that), you and
Stormy need to find a good eye doc who will check for other problems.
It's a whole lot easier to prevent blindness than to correct it.

Even though I have purchased a set of trial lenses (and I have already
determined that the astigmatism correction in one eye is off by at
least ten degrees, but more on that after I've had some more time to
play), I will still go for an annual checkup at the ophthalmologist.