Visual performance describes the ability of a person to detect, identify and analyze the details contained in his field of view, taking into account the speed, the quality and the accuracy of his perception.
Visual performance depends, on the one hand, on the inherrant characteristics of the task to perform (dimension, shape, position, colour or reflectance of the details and the background), and on the other hand, on the perception, which is influenced by the lighting condtions (uniformity, glare, etc).
Visual performance is also affected by other parameters such as the observer's visual system ability, the external factors lowering attention, the nature of the background and, more generally, the way that the working space is organized.
A decrease of visual performance can be the result of a disability glare situation. As opposed to discomfort glare, disability glare describes a situation in which visual performances are impaired without necessarily causing any discomfort sensation.