An Approach to Vision Disturbances Caused by Human Cerebral Lesions

Damage to the occipital lobe and in the adjacent temporal and parietal cortex results in a variety of defects of visual perception and cognition (see Table 1). The neuroophthalmological approach to these disorders has been limited. A historical factor is Holmes' view that all basic visual 'impressions' depend entirely on striate cortex (also called Brodmann's area 17, or area VI). This view probably hindered the understanding of cortical visual disorders by delaying identification of extrastriate cortex as zones that process the output of area VI. Another factor is that brain-damaged individuals may provide an impoverished or misleading report to their examiners. Finally, standard neuro-ophthalmological procedures often do not address the underlying defect in cortical cases.