A novel psychophysical visual test based on the visual response of the eye to alternating chromatic complementary colors or achromatic grays of varying saturation, luminance and/or contrast is proposed for the early detection of glaucoma, and other diseases. In one embodiment, although the luminance level remains constant, the visual stimulus alternates between two complementary or counter phase colors, preferably against a gray background at about 40 time a sec, for example, between blue and yellow. When the colors are alternated in this manner, the visual stimulus appears white or gray to an observer, instead of either blue or yellow. When the colors are alternated in this manner, the visual stimulus appears white or gray to an observer, instead of either blue or yellow. As the saturation is reduced, however, the alternating colors appear grayer, and then eventually cannot be perceived. Persons suffering from glaucoma and other diseases, however, find it more difficult than normal people to distinguish the visual stimulus as the saturation and/or luminance is reduced. The patient views color monitor (130) at a predetermined distance for the stimulus to subtend a predetermined angle. An operator may be seated at or near computer (110) for controlling the test parameters via a keyboard (150).
VISUAL TEST