Sensitivity of the Retinal Area in One Eye Corresponding to the Blind Spot in the Other Eye*

Threshold sensitivity was studied in six observers on one vertical and three horizontal lines running through an area in the nasal visual field of one eye which corresponds to the blind-spot region of the other eye. The test fields were squares of 1° angular subtense on a side and were presented for 0.04 sec. Thresholds were found to be lower in this region than at retinal points immediately outside, yielding a mean increase in sensitivity of approximately 0.25 log unit. The findings are discussed in regard to density and innervation of retinal elements, cortical representation, and the possibility of compensation for lack of sensitivity in the blind spot in order to maintain uniform brightness in an integrated binocular field of vision.