Pinhole glasses, also called stenopeic glasses, are eyeglasses with an opaque sheet of plastic having a grid of tiny holes. Pinhole glasses help eyes focus on particular object directly by shielding vision from the indirect rays of light. Pinhole glasses are used by people to correct myopia or astigmatism.
Pinhole camera is a similar apparatus of a camera without a lens. A tiny pinhole is the point of entry of light from the object of focus. The image falls on the screen at the end of the camera. Pinhole occluder is a device used by ophthalmologists and optometrists to help in diagnosis of refractory errors that works on the same principles as pinhole glasses.
Each hole in the pinhole glasses allows the entry of a very narrow ray of light reducing the blurring effect on the retina and improves depth of the field. However, they reduce brightness and peripheral vision for the person and cannot be used while driving or operating machinery.
Although pinhole glasses help focus objects right in front, they also block various parts that is being looked at. So, they are not functional for everyday use for reading or near-sightedness.
Some people believe that wearing pinhole glasses for a specific amount of time every day can improve vision and refractory errors. But there is no conclusive evidence or trials that can confirm this.
Types of Pinhole glasses:
Claims of pinhole glasses improving the refractory errors on a permanent basis have not been proven scientifically. Formal clinical studies are required for various countries mostly for legal settlement issues. Pinhole glasses should never be used for looking at the sun during a solar eclipse. However, pinhole projector can be made to view the eclipse by standing with the back to the sun and viewing it inside the box.