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Do pinhole glasses work?
January 24, 2010 4:41 AM   Subscribe

I found this pinhole glasses sold at the local pharmacy, and feel intrigued by its claim to help me see better and improve my vision overtime (I'm short-sighted). My skeptic alarm rang with warnings (if it's too good to be true, it usually is, etc.), but a quick google-fu turned up nothing substantial to refute such claims. So, does anybody have any experience or anecdotes to share in regards of such product ?
posted by joewandy to Health & Fitness (16 answers total) 2 users marked this as a favorite
 
20/800 anecdote here. An opthamologist once told me that it is possible to improve nearsightedness by alternately focusing on near and distant objects.

His explanation was that the visual defect in my case was caused by the inability of the eye muscles to shape the lens properly so as to focus; and that the muscles, like any other, could be strengthened by exercise.
posted by minimii at 4:47 AM on January 24, 2010


Well, my understanding is your eyes work by 'squeezing' your eyes to focus on close objects. If you're nearsighted (i.e. have Myopia), then your eyes are already too 'long', and there is no way for the muscles in your eye-sockets to 'unsqueeze' them.

On the other hand, if you need reading glasses, it's usually because the muscles in your eye aren't strong enough any more, and they can be improved by strengthening the muscles, so people who take steroids sometimes have their vision improve.

The pinholes might help you see better while you're wearing them, just like regular glasses would, except they would work by (essentially) making your "aperture" smaller. Smaller aperture = longer depth of field = more stuff in focus.
posted by delmoi at 4:52 AM on January 24, 2010


Do pinhole glasses work? Hi, I'm Fake, and I am a graduate student studying visual neuroscience. I'm here today to answer your pinhole glasses question, however I am not going to say much about neuroscience.

First of all, pinhole glasses "work". By that, I mean that if you are nearsighted (myopic) and you wear them, you will indeed see distant objects more clearly, at least under certain conditions (more on this in a minute). HOWEVER:

The claims about "muscle exercises" and improving your vision over time are complete crap. Ignore them. They came from an old, debunked idea (made famous by a man named Bates) that you could correct the eye by exercising the muscles around it, and also by doing insane shit like burning it with a magnifying glass to acclimate the eye to bright lights. These claims about eye exercises are bogus, but persist because they are so lucrative. You can, to some degree, correct a strabismic eye (which is when the two eyes are not muscularly coordinated), but you cannot correct hyperopia (farsightedness) or myopia (nearsightness) by wiggling your eye muscles. In most cases these problems come from the entire eyeball having a squashed shape or an oblong shape. For this reason, it is rumored that Air Force candidates with poor vision mash their eyes into their heads before vision exams to temporarily correct for their visual dysfunction. The correction lasts for a couple minutes.

Even if you could correct your vision in this way, everyone's eyes degrade irreversibly as they age, due to to the gradual hardening of fibers in the crystalline lens. That usually makes it harder to see close up, rather than far away.

OK, back to pinhole glasses. Pinhole glasses work the same way pinhole cameras work. Pinhole cameras are "lensless" -- the "lens" is the little hole. Roughly speaking a normal lens collects light and refracts it so it lands at the right place and in-focus. But a pinhole works by blocking most light rather than redirecting it. By "choosing" a small pencil of rays with a tiny hole, light rays that aren't coming straight in, which would cause blur, never make it to your retina. As a consequence, the image on your retina will appear better focused with the glasses than without. As you can see, this does nothing to exercise you eye or improve your natural visual capability.

Which is not to say it isn't useful -- in fact, it appears in survivalist literature because you can make pinhole glasses with your bare hands. In this way, if you're stranded on a desert island, you can see well enough to survive even if you've lost your spectacles.

But remember, pinhole glasses work by RESTRICTING light. So sure, you can see better with pinhole glasses... on a glaringly sunny day. They won't help you read a book under dim light, or at night, or really any other time. They are sunglasses and not much more. And since you can make them with nothing more than your skin and bones, at the moment you need them, I recommend ignoring this snake-oil salesmanship and sticking with the hard-won insight of optometry and vision science, namely, glasses and contacts and lasik.
posted by fake at 5:33 AM on January 24, 2010 [38 favorites]


Wow, the Wiki is good.

"The trust about pinhole glasses"
"Eye-Related Quackery"
posted by fake at 5:41 AM on January 24, 2010


Here's a cool video demonstration with a leaf and a video camera.
posted by fake at 5:45 AM on January 24, 2010


Very helpful information all around (especially Fake). Thanks all!
posted by joewandy at 5:47 AM on January 24, 2010


The claims about "muscle exercises" and improving your vision over time are complete crap. Ignore them. ... but you cannot correct hyperopia (farsightedness) or myopia (nearsightness) by wiggling your eye muscles.

Fake, I did read an article by someone who went on HGH/Steroids for a magazine article. He reported that he no longer needed reading glasses after taking HGH. I doubt that wiggling your eyes would help much but it does seem to be the case that HGH/steroids can strengthen the focusing muscles in your eyes.
posted by delmoi at 6:14 AM on January 24, 2010


Oh and of course it's also the reason why your vision improves when you squint (although there may be some reshaping as well)
posted by delmoi at 6:15 AM on January 24, 2010


(fake's pinhole glasses link is also an old printer's trick. If you can't find your loupe, but still need to magnify your type, "pinhole hands" give you the ability to focus closely)
posted by scruss at 6:33 AM on January 24, 2010


but it does seem to be the case that HGH/steroids can strengthen the focusing muscles in your eyes.

As you know, and as you've argued elsewhere on the site, one subjective report doesn't prove anything. If you read the article on orthoptics that I linked above, you will see that the primary author is an OD who agrees with my lay opinion, and backs it up with cites from optical societies and journal articles. Muscular/behavioral therapy is useful for some disorders, and myopia, the OP's problem, is not among them.

Oh and of course it's also the reason why your vision improves when you squint (although there may be some reshaping as well)

It's not clear what you mean here, if you mean that squinting improves vision by restricting incoming rays, that is correct, however, the higher-order diffraction effects of the non-circular aperture and the curvature of the fluid resting on the surface of the eye degrade the image relative to a pinhole.
posted by fake at 6:38 AM on January 24, 2010


As you know, and as you've argued elsewhere on the site, one subjective report doesn't prove anything.

True. But the article did seem credible when I read it. Okay, here we go I managed to find the article.

Here's what he said:
Then I started to realize that my eyesight really was improving. I'd been thinking about getting glasses to read fine print on maps, but now there was no need. The glasses I used for night driving stayed in the glove compartment, unused, unnecessary.
I guess that is pretty subjective. And his doctor 'primed' him by telling him it might make his vision better first, which obviously have a big impact on the placebo effect.

It's not clear what you mean here, if you mean that squinting improves vision by restricting incoming rays, that is correct, however, the higher-order diffraction effects of the non-circular aperture and the curvature of the fluid resting on the surface of the eye degrade the image relative to a pinhole.

Yeah, that's what I meant. Most people with bad vision will notice that it gets a little better when you squint, but obviously not as good as when you wear glasses. Of course it's also possible that the improvement could come from squeezing the eyes when you squint as well, I don't know.
posted by delmoi at 7:25 AM on January 24, 2010


(fake's pinhole glasses link is also an old printer's trick. If you can't find your loupe, but still need to magnify your type, "pinhole hands" give you the ability to focus closely)

I saw this on some science-related video podcast. If you're stranded on a desert island and have lost your glasses, if you touch your index fingers and thumbs together and make a tiny pinhole, you can look through that and see (somewhat) things far away.
posted by Lucinda at 7:53 AM on January 24, 2010 [1 favorite]


Pinhole glasses increase depth of field exactly like stopping down a camera aperture. You can see how this works yourself with a simple exercise: Close one eye and hold one finger up in front of you. If you focus on the finger, the background is out of focus. If you focus on the background, your finger is out of focus. You can't have both (normally we assume everything is in focus because our eyes focus so quickly). Now punch a pinhole in a piece of black paper, close one eye and do the same finger exercise looking through the pinhole, and you'll find that both the finger and the background are in focus. The trade-off is that everything gets much darker, so these glasses will only work effectively in bright light. You can get pretty much the same effect by squinting.
posted by weapons-grade pandemonium at 8:56 AM on January 24, 2010


Thanks for the info, Fake. Now I don't feel so bad that hours of back and forth staring did nothing to forestall my descent into Mr. Magoo-land. And yes, I do have a new opthamologist.
posted by minimii at 9:33 AM on January 24, 2010


Wow, pinhole hands is awesome! How did I not know about this?

*Goes back to peering between fingers*
posted by diogenes at 10:27 AM on January 24, 2010


Actually, lucinda, pinhole hands allow you to close focus too, as they have (almost) infinite depth of field
posted by scruss at 5:41 PM on January 25, 2010


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