Component perimetry: A fast method to detect visual field defects caused by brain lesions

PURPOSE. Noise field campimetry, performed according to Aulhorn and Kost, c onfronts patients with a large field of irregularly flickering dots, and ma ny patients immediately perceive their visual field defects. The original m ethod had a somewhat low specificity and sensitivity, especially for patien ts with visual field defects caused by cortical lesions. METHODs. The method was improved in two wags. First, the grain of the visua l noise was increased toward the periphery of the visual field to accommoda te the peripheral decrease in visual acuity. Second, the type of stimulus p attern was varied to include separate investigations of different visual co mponents or functions (color, motion, temporal resolution, line orientation , stereoscopic depth, acuity, and figure-ground segmentation). To evaluate the reliability of the method, the visual fields were compared, as assessed by the new method, with those of conventional perimetry in 41 patients wit h neurologic disorders and 22 normal control subjects. RESULTS. The results were encouraging. All patients with suprageniculate le sions subjectively experienced visual field defects in component perimetry. Sizes of visual field defects obtained with both methods corresponded qual itatively with each other, with a highly significant correlation. The speci ficity of component perimetry nas higher than that of the original noise fi eld campimetry. CONCLUSIONS. This pilot study indicates that component perimetry is a subje ctive but relatively reliable method for detecting disorders of visual perc eption caused by lesions at different stages along me visual pathway, permi tting fast screening of the visual held. In addition. this method seems to allow examination of the visual held, nor only for defects in contrast sens itivity, as does conventional light perimetry, but also for the status of o ther components of vision such as color or motion perception. Further evalu ation with larger patient cohorts is needed to allow exact assessment of th e clinical usefulness of the method.