pinhole

When we are checking your vision in our office, one of the most common tests we perform is called the “pinhole test.”  After you read the eye chart wearing your glasses, we recheck your vision while you look through a plastic patch that has little holes punched through it.  Many people will actually see better when looking through the pinholes … reading several lines lower on the eye chart. This pinhole improvement is usually an indicator that your glasses need to be updated. The pinhole test works because it turns your eye from a “focusing telescope” system into a simple “pinhole camera.”  Pinhole cameras have no lenses and don’t need to be focused like a traditional camera … by letting light into the camera through a tiny pinhole, the image is always in focus. Many small cameras, such as the one in your cell phone, use a pinhole and require little focusing. The eye is much larger, however, and needs to be focused like a telescope. The pinhole test is pretty cool, but unfortunately we can’t make your glasses this way as the pinhole effect is pretty dim and would really mess up your peripheral vision. However, if you ever find yourself on a deserted island and the natives steal your glasses, you may be able to construct your own pinhole glasses out of shells or leaves and see well enough to survive!  If this happens and you make it back alive … please let me know and consider adding me to your will.

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Dr. Timothy Root is a practicing ophthalmologist and cataract surgeon in Daytona Beach, Florida. His books, video lectures, and training resources can be found at:

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