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View Full Version : Why can the farsighted buy cheap glasses at Walgreens but not the nearsighted ?


lamerino
04-05-2000, 02:33 PM
Why can the farsighted buy cheap glasses at Walgreens but not the nearsighted?
I can get $10 reading glasses, but pay $75 or more for driving glasses. (And it's not the quality, as Sixty Minutes pointed out.)

BobT
04-05-2000, 02:42 PM
It behooves you to get glasses that are of the proper prescription for driving, where you might hurt someone, as opposed to reading, where the chances of you hitting someone with your book are slim.

lamerino
04-05-2000, 03:01 PM
Every time I'm in the Department of Motor Vehicles line I see people who struggle with the chart and get by with one or two wrong. If glasses were $10 and didn't require an appointment, that would be safer.

Also, I suspect that like a lot of medical law, the rule is older than the automobile, although that's a guess. Anyone remember when such laws were last debated?

tanstaafl
04-05-2000, 03:12 PM
It's a lot easier to cure farsightedness than nearsightedness. The reading glasses you see at Walgreens are basically magnifying lenses; just put a powerful enough lens in the glasses and anyone will be able to see up close. Yes, they let you read but you have to remove them in order to get distance vision again.

Glasses for nearsightedness are more complicated in lens design and have to be fitted with more tolerance in order to allow the wearer to have both distant *and* close vision.

To use the driving example again; when you are reading a book it is no problem to remove your glasses when you get up to do something else. When you are driving it would be a problem to keep removing and replacing your glasses whenever you went from looking out the windshield to looking at the dashboard.

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Yarster
04-05-2000, 05:11 PM
Funny you should ask...

Once apon a time, if you wanted a prescription SCUBA mask, they gave you pop-in lenses for something like $15 a set based on what was 'close' to what you needed. That's what I did about 7 years ago. My wife just got one as well, and they now have to send it out to an optical place to have the exact prescription filled, which translated to a fairly major cash outlay for the mask (both 'Liberator' brand if that matters). I guess they have to assume you might drive it :)

lamerino
04-05-2000, 06:19 PM
tanstaafl quote:

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Glasses for nearsightedness are more complicated in lens design and have to be fitted with more tolerance in order to allow the wearer to have both distant *and* close vision.
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No. I guess you never studied lenses, but all simple (non-bifocal, non-astigmatism-correcting) lenses are ground the same way on the same machines. They are spherical in shape, with one surface a slightly different radius than the other.

What make them work "both near and far" is the human lens, which is stretched by the eye muscles to flatten it (like pulling on the edges of a round pillow will flatten it.)

You're probably under 45, or you'd know that over the years that lens/pillow adds layers
until it becomes "overstuffed". It can no longer flatten when pulled, no longer works "both near and far", and bifocal lenses, or two pairs of glasses are needed to get the same "depth of field".

That said, the real question is back to cost and availability.

handy
04-05-2000, 09:49 PM
Im with the magnifying poster...thats all they do, magnify.

Your eyes have to work right together & thats why one should always get prescription glasses. In other words, each eye may be just fine by itself, but how they work together is another thing.

Billdo
04-05-2000, 11:22 PM
Originally posted by Yarster:
Once apon a time, if you wanted a prescription SCUBA mask, they gave you pop-in lenses for something like $15 a set based on what was 'close' to what you needed. That's what I did about 7 years ago. My wife just got one as well, and they now have to send it out to an optical place to have the exact prescription filled, which translated to a fairly major cash outlay for the mask (both 'Liberator' brand if that matters). I guess they have to assume you might drive it :)

Last year I got a scuba mask with the perscription lenses that they just popped in for about $10 each. The lenses were not my exact perscription and did nothing for my astigmatism, etc., but the worked just fine underwater. I got them in my local dive shop here in NYC, but I also saw they were available from dive stores on the internet.

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scr4
04-06-2000, 12:03 AM
When elderly people become farsighted, the eye muscles get weak and the range of focus decreases. When young, one can focus from, say, 6 inches to infinity. When you get older, this may become 4 feet to 100 feet. So you buy reading glasses and move the range to, say, 1 foot to 10 feet. The prescription is not very critical here, because 1/2 feet to 5 feet range works just as well for reading.

Nearsighted people are usually that way because the range of focus moves closer, but not narrower. Say 2 inches to 1 foot. If you get the correct prescription, you can move that to the normal 6 inches to infinity range. If the glasses are too strong you will have trouble with reading; too weak and you can't see very far or be able to drive.

There are also people who are far-sighted when young. They have a full range of focus but the range is shifted farther. Say 3 feet to farther than infinity. (Light from a nearby object is diverging strongly, and light from object at infinity is parallel, so if light is converging, it is said to be farther than infinity). As far as I know, those people have prescription glasses to move the focus to the proper range.

sailor
04-06-2000, 12:47 AM
The main difference between reading glasses and near sighted prescription glasses is that reading glasses have a simple prescription, both sides being equal and no astigmatism etc while people who are nearsighted often have different prescriptions on each eye and astigmatism. This makes it impossible to have a wide range of ready-made eyeglasses as there are millions of combinations.

BUT... Eye care professionals have managed to convince everyone that we cannot do anything without them. The fact is that both lenses and frames are incredibly cheap and have incredibly high markups.

I have been very nearsighted all my life and the prescriptions I have been given were often quite bad and I would have done better on my own. I have a very simple prescription (both eyes the same and no astigmatism) and yet they make it complicated and expensive

Not only that but they always try to sell me tinted lenses and other add-ons that I do not want or need trying to convince me there are medical reasons to reccommend them. Pretty unethical if you ask me but they're trying to sell you stuff

This is just a case of a group defending their monopoly. I remember some years back in Spain you had to go to an ophthalmologist's clinic to buy contact lens liquids. The argument is that you cannot play with your eyes.

The phone company also used to want to be the sole supplier of anything you may plug into their line...

I just came back from China where eyeglasses are incredibly cheap and I came back with 5 pair for about $10 each. Not only that but the guy who did my eye exam was much more willing to listen to my opinion than most western optometrists who think they know better than the patient. Even with the language barrier I was more satisfied than I have ever been before.