Stenop glasses are a visual aid that replaces traditional lenses with dozens of small holes. Also known as pinhole or rasterbrille glasses, they are usually made of metal or plastic. The glasses work on the principle of stenopeic vision — looking through the holes leads the mind to think that vision is focused, making the glasses useful in treating a number of eye disorders. Eye disorders such as myopia are caused by the eye improperly refracting light; stenop glasses block out light and keep the vision centered.
Stenop glasses are most popular for relieving the symptoms of cataracts, but can also be used to treat a wide range of eye ailments such as hyperopia, presbyopia and myopia — reducing those symptoms by up to 80 percent. Although they can improve vision they should be used cautiously; they shouldn't be used while operating machinery or driving because they can reduce peripheral vision.
Spanish designer Nacho Marti created an inexpensive, easily transportable version of stenop glasses as a "first aid kit" for people in developing countries. Traditional glasses can be prohibitively expensive to people in developing countries, and Marti's glasses provide a solution for children and adults who have to rely on charity shipments from other nations. Although stenop glasses can be almost as expensive to produce as traditional glasses, Marti's design makes it possible to produce a large volume of them quickly and cheaply. His stenop glasses have received design awards and have been received attention throughout the world.
Stenop glasses are touted by some in the natural health field as a permanent alternative to traditional crystal glasses; they say that stenop glasses help train the eye and, combined with particular eye exercises, can reverse eye damage. Although stenop glasses can provide a short-term solution to eye problems, they are not currently endorsed by the medical community at large as a permanent treatment.