COLOR-VISION AND COLOR PATTERN VISUAL-EVOKED CORTICAL POTENTIALS IN APATIENT WITH ACQUIRED CEREBRAL DYSCHROMATOPSIA

We examined a 74-year-old man because of difficulty seeing green and t he presence of prosopagnosia. His visual acuity was 0.8 in both eyes. He was not congenitally color blind, and there was no family history o f color blindness. A left superior homonymous quadrantanopsia was foun d. The dyschromatopsia was identical in bath eyes. The patient showed red-green deficiency on testing with Ishihara plates a deutan defect w ith Tokyo Medical College plates, strong blue-yellow defects and mediu m red-green defects with Standard Pseudochromatic Plates II and a trit an defect with the Panel D-15. He failed the New Color separation test with scores of 160 and could not carry out the Farnsworth-Munsell 100 -hue test, but his color naming test results were normal. Visual evoke d cortical potentials to black-and-white checkerboard and color patter n reversal (Red and Blue-Green, Green and Red-Purple, Purple and Yello w-Green: isochromatic paired checks) stimuli were normal. Bilateral in ferior occipital lesions were found by computed tomography and T-2-wei ghted magnetic resonance imaging. Our findings suggested that luminanc e and color channels up to area 17 in our patient were intact. We beli eve that our patient's acquired cerebral dyschromatopsia is rare.