Pinhole Glasses

Pinhole glasses, also known as stenopeic glasses (from Greek meaning “little opening”), are eyeglasses with a series of pinhole-sized perforations filling an opaque sheet of plastic in place of each lens. It works on the same principle of the pinhole camera; each hole allows only a very narrow beam of light to enter the eye which focuses on the retina and increases the depth of field. In eyes with refractive error, the result is often a clearer image. Unlike conventional prescription glasses, pinhole glasses produce a clear image without the pincushion effect around the edges (which makes straight lines appear curved). While pinhole glasses are useful for people who are both near- and far-sighted, they are not recommended for people with over 6 diopters of myopia. It should also be noted that pinhole glasses reduce brightness and peripheral vision, and thus should not be used for driving or when operating machinery.

Pinhole glasses have been marketed by various companies on the claim that—combined with certain eye exercises—they could permanently improve eyesight. These claims have been analyzed, but no scientific evidence has been found to support them, and the claims are no longer allowed to be made in the United States under the terms of a legal settlement with the Federal Trade Commission.