LF15 The importance of glare and calculating UGR (2019) (pdf)

Glare is the sensation where the eye percieves areas of brightness within the visual field, which can result in a person having difficulty seeing or carrying out a visual task. The light source may be the sun or artificial, and glare can arise from windows, roof lights, luminaires or reflections of these from under the surfaces. Often the natural reaction would be to shield our eyes from it. Excessive glare can lead to errors, accidents and fatigue.

There are several froms of glare, but when we talk about glare in the built environment, we are generally talking about two particular types, disability and discomfort.

This is one of the Society of Light and Lighting's series of freely available factfiles, all of which are available here:

SLL Lighting Factfiles