ABSTRACT
This chapter explains the eye and light, provides specific recommendations for reducing visual problems, and then makes design recommendations for general and special lighting. First, the eye anatomy will be discussed, then vision. Visual performance is affected by individual differences, quantity of light, quality of the light, and task requirements. Regardless of the amount of illumination, performance on easy visual tasks far exceeds performance on difficult visual tasks; that is, more light will not change a difficult task into an easy one. The ideal illumination source would be free, give the desired amount of light on demand, and have high quality. Normal eyeglasses are "single vision" glasses; they have one focal point, generally infinity, that permits far vision and near vision. However, a person who has a prolonged need for near vision (reading, computer use, dentistry) may use single-vision glasses ground for a specific near distance (say 16 inches for reading, 28 inches for computer monitors).
