A few of you have noticed ads for “pinhole glasses” – glasses with multiple pinhole-sized holes on each side instead of prescription lenses. Do they work? Well, sort of…
Pinhole glasses actually “work” in the sense that they do provide a clearer image for most people with refractive errors (i.e. nearsightedness, farsightedness, and/or astigmatism). The reason is that they work on a different optical principal. In simple terms, when you severely limit the amount of light entering your eye through a small pinhole, you can actually bypass the need for corrective lenses! This is why a “pinhole camera” works using a simple cardboard box with a small hole at one end. Many organisms that have little use for sharp vision in their environments will not have a developed lens system, as our eyes do, instead will function with just a pinhole which gives them “enough” vision to function in their habitat.
The problem with pinhole glasses is the fact that by definition you need to cut down the amount of light entering the eye significantly. This causes problems with visual function since we need adequate lighting to perform well visually on a day to day basis. In addition they can be dangerous since they will severely alter our peripheral vision, making tasks like driving extremely risky.
So the science behind pinhole glasses is sound, and they will provide a clearer image than wearing no glasses at all. They will never provide an image that is as clear as what a set of prescription lenses will provide. Also they will not strengthen your eyes with repeated use, contrary to claims made by certain manufacturers of pinhole glasses. In fact, due to the limitations I mentioned, they are much more likely to cause symptoms of headache and eyestrain if used frequently, which may actually worsen your vision condition. For this reason we do not endorse the use of pinhole glasses.
Thanks to Jessica for your question on one of our recent blogs which inspired this article.
– Dr. Wilk