Pinhole glasses

Pinhole glasses, also known as stenopeic glasses, are eyeglasses with a series of pinhole-sized perforations filling an opaque sheet of plastic in place of each lens. Similar to the workings of a pinhole camera, each perforation allows only very narrow beam of light to enter the eye which reduces the size of the circle of confusion on the retina and increases depth of field. In eyes with refractive error, the result is often a clearer image, akin to that created by corrective glasses, although significantly darker, lower in contrast, and prone to flickering. Pinhole glasses reduce peripheral vision.

Compared with conventional lenses, pinhole glasses may restrict contrast, brightness, and the field of view.

Applications
Advocates of natural vision improvement methods assert that pinhole glasses can be used as a vison improvement tool and often as a substitute for conventional eyeglasses. Those who sell pinhole glasses claim that they can eliminate eye strain due to computer use. Others claim that their use not only results in improved vision, but that prolonged use can actually cure myopia. Optometrists state that these claims are not supported by any objective evidence.

They have been touted as low-cost vision correction for people in underdeveloped countries, where refractive glasses may be too expensive