Types of glare
Discomfort glare from a light source or luminaire, where brightness is greater than the eye can adapt to, makes a task uncomfortable to perform. The degree of discomfort depends on several factors; the brightness and the size of the glare source, the position of the glare source in relation to the line of sight, and the background luminance against which the glare source is viewed.
Disability glare is caused by a reduction of contrast which leads to a decrease in visibility. This type of glare describes the situation when the ability to perform is adversely affected i.e. driving when the sun is low in the sky or towards a vehicle using full beam headlights. Traditionally, disability glare would be associated with incidental issues such as those described and not associated with modern lighting design practice or product technology.