Defective stereopsis in lesions of the parietal lobe.

Little is known about the localization in the brain of fusion of disparate images from each retina to create the sensation of stere­ opsis. One might expect the visual associa­ tion cortex in the parietal lobe to be in­ volved, but information about the effect of parietal lobe damage on stereopsis is scanty. Perhaps the most significant work con­ cerning the localization of stereopsis was that of Carmon and Bechtoldt. Using a modifi­ cation of the computer-generated stereograms of Julesz—a complicated technique which is not generally utilized—they found that patients with lesions involving the right cerebral hemisphere exhibited significant deficits in stereopsis. In this paper, it is our intent to evaluate the role of the parietal lobes in stereopsis, using a simple, inexpensive, readily available device, the Titmus Stereotest.