Pure homonymous hemiachromatopsia. Findings with neuro-ophthalmologic examination and imaging procedures.

The study describes neuro-ophthalmologic findings in two patients with brain infarction who developed homonymous hemiachromatopsia with resolution to pure homonymous achromatopsia in an upper quadrant. All other visual parameters were normal; only color perimetry was capable of demonstrating the visual disorder. The results are presented with special emphasis on the macular region. Computed tomography studies and magnetic resonance imaging revealed lesions in the caudal and medial occipitotemporal gyri as well as in adjacent cortical regions. The lesions were secondary to disordered circulation in a proximal occipitotemporal branch of the posterior cerebral artery. The anatomical findings and functional relations of color vision in man are discussed in the light of animal findings.