Pinhole glasses

Pinhole glasses
The effect of pinhole glasses approximated by a camera
An eye chart in sharp focus, as would be seen under normal vision.
A blurred eye chart, as would be seen by an individual with a refractive error.
Pinhole glasses, when placed over the out of focus camera, make the chart somewhat readable once more. However, they darken the image and the grid blocks some of the finer details, requiring slight movements of the camera for the whole chart to be somewhat comfortably read.

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.

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