A static perimetric technique believed to test receptive field properties: Responses near visual field lesions with sharp borders

The organization of the ‘Westheimer function’ in the retina has been further analysed. Patients with sharp visual field cuts caused by chiasmal and cortical lesions have been studied. Data were generally obtained from points approximately 10°–15° from the fovea (where areas of spatial interaction and the magnitude of the inhibitory component were large). The center of the three field display was placed just within the boundary of the sighted area of the visual field. Hence, a substantial part of the background field fell on nonsighted areas, which presumably retained retinal function. If the inhibitory part of the function originates proximal to the retinal ganglion cell layer (or the underlying retina was nonfunctional), then the basic ‘Westheimer function’ probably would be altered when these data are compared with findings obtained at a normal point in the visual field of the affected eye. All cases measured to date exhibited essentially unaltered functions. This finding, plus previous studies of patients with inner retinal diseases, places the locus of the measured inhibitory component of the Westheimer function most probably in the inner retina. This research has been supported in part by Research Grants No. EY 00204 and EY 00233 and Career Development Award No. K3 EY 15138 (to J.E.) of the National Eye Institute, National Institutes of Health, Bethesda, Maryland.