n. a rare defect of colour vision in which affected persons are insensitive to blue light and confuse blues and greens. Compare deuteranopia; protanopia.
n. a defect in colour vision in which reds, yellows, and greens are confused. It is thought that the mechanisms for perceiving red light and green light are in some way combined in people with this defect. Compare protanopia; tritanopia. See also colour blindness.... deuteranopia
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