NO BLINDSIGHT FOLLOWING HEMIDECORTICATION IN HUMAN-SUBJECTS

USING a guessing paradigm we measured visual sensitivity in the blind and normal half-fields of four cerebrally hemidecorticated patients. I n the blind field, sensitivity was reduced by similar to 3 log units. Stimuli which produced significant detection also evoked conscious sen sations of light and colour. Control experiments showed that although sensitivity in the blind field depended in a normal fashion on backgro und luminance, it was independent of the luminance of a local platform , and showed no spatial summation. This residual vision can be explain ed by intraocular light diffusion and reflection.