Ocular straylight is a phenomenon where parts of the eye are able to scatter light, creating glare.
One can observe the effect of straylight by looking at a distant bright light source against a dark background.
The disability glare caused by such a situation has been found to correspond precisely to the effect of true light.
[1][clarification needed] As a consequence, disability glare was subsequently defined by this true light, called "straylight".
Aging of the crystalline lens of the human eye causes straylight to become worse.