1. Glare and luminance of luminaires

Glare is undoubtedly one of the main causes of discomfort. It takes two different forms, which may coexist:

• incapacitating glare, which reduces visual performance by causing hazy luminance to appear in the eye;

• discomfort glare, which causes discomfort without necessarily affecting visual performance.

Incapacitating glare depends mainly on the quantity of light falling on the eye and relatively little on the luminance of the sources, whereas in discomfort glare, the latter plays a dominant role.

In practice, in the panorama, discomfort glare is much more frequent than incapacitating glare. What's more, controlling discomfort glare almost always results in the disappearance of incapacitating glare. The search for ways of calculating and evaluating...