Ask Dr. Schauer ~ Pinhole glasses

“We went out to eat with my in-laws and they used very strange eyeglasses to read the menu. The glasses looked like horse blinders! These huge glasses had black patches over both eyes with very small holes in them. They insisted that reading through the small holes would improve their vision. I tried them and it really strained my eyes. Is this real? Have you heard of such a thing?”

Strangely enough, we know exactly the type of eyeglasses our listener is asking about. Then are called pinhole glasses.

What is the pinhole effect?

Have you ever noticed that if you squint your eyes that your vision seems to be more clear? That is the pinhole effect.

If you spend any time doing photography, you probably have heard of depth of field. This is similar to the pinhole effect. When you only allow a small amount of light to enter through the aperture, it eliminate any out-of-focus peripheral light which makes your target image more clear.

How is the pinhole effect used?

As mentioned, photographers are very familiar with optics and how changes to the aperture make changes to the image you are taking. But we also may sometimes use the pinhole effect during an eye exam. If vision is improved while looking through a pinhole, we know that eyeglasses or contact lenses can improve visual acuity. However, if vision is not improved, then we know that there must be ocular pathology causing the decreased vision.

Does wearing pinhole glasses improve your vision?

Depends what you mean by “improved vision”. Will it decrease your need for eyeglasses in the future?

No.

Just like no amount of exercise or stretching will allow me to be 6 feet tall, wearing pinhole glasses will not change your eyeglasses prescription in order to decrease your need for eyeglasses.

We also would not recommend using pinhole eyeglasses for normal daily activities due to the potential for eye strain and the extremely reduced visual field.

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The content on this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.