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defective vision or blindness in one fourth of the visual field.
Loss of vision in a quarter section of the visual field of one or both eyes; if bilateral, it may be homonymous or heteronymous, binasal or bitemporal, or crossed, for example, involving the upper quadrant in one eye and the lower quadrant in the other.
Synonym(s): quadrantic hemianopia
quadrantanopia/quad·rant·an·o·pia/ (kwod″ran-tah-no´pe-ah) defective vision or blindness in one fourth of the visual field.
Visual field loss in a quarter of the visual field of the eye. The defect is usually bilateral, as it is caused by a lesion past the optic chiasma. It may be homonymous (binasal, bitemporal, upper or lower), crossed (one upper and the other lower), congruous (equal size of the defects), or incongruous (unequal size of the defects) (Fig. Q1). Syn. quadrantanopsia; quadrantic anopsia; quadrantic hemianopia. See hemianopia.