Stereopsis and color vision impairment in patients with right extrastriate cerebral lesions

Background and Aim: The extrastriate cortex is a visual processing structure beyond the striate cortex. This region contains cells that differ in selectivity for different features of stimuli such as color, motion and stereopsis. We studied stereopsis and color vision in patients with right extrastriate cerebral lesions. Methods: Patients with right extrastriate cerebral lesions determined by MRI were recruited among consecutive inpatients. Patients with cognitive impairment (Mini Mental Status Examination score <24) were excluded. An ophthalmologist performed cortical visual testing: visual acuity, stereopsis, color vision and strabismus within 1 week after the insult. Results: Cortical visual testing was performed in 12 patients. Among the patients studied, 11 demonstrated abnormalities: reduced stereoacuity (8/12), color vision abnormalities (7/12). Seven patients showed complex cortical visual abnormalities. However, only 2 patients complained of subjective clinical symptoms. The MRI lesions in patients with disturbance of stereopsis were located in the dorsal occipitoparietal area and the ventral occipitotemporal area. Color vision abnormalities corresponded to lesions in the ventral occipitotemporal area. Conclusions: Patients with lesions in the right extrastriate cortex tend to have disturbance of stereopsis and color vision abnormalities, even in the absence of visual complaints.