Clinical interest and problems related to the measurement of the blind spot and the pericoecal region by means of programs SAPRO, SAPPAR, and BSPOT.

Difficulties encountered when measuring the differential light sensitivity of the blind spot and its surroundings and the clinical interest of such measurements are reported. The determination of the differential light sensitivity across step gradients, as well as abrupt changes observed at and close to the blind spot, may pose severe problems, because both are strongly influenced by even slight fixation instability. However, other factors reported herein may be equally important. The insight gained here may be cautiously extrapolated to the difficulties (and to the efforts to overcome them) encountered when measuring other scotomata in the visual field having sensitivity distributions similar to those of the blind spot. The sensitivity distribution in the blind spot and the pericoecal region may be important in a number of disease entities, particularly in glaucoma and neurologic diseases.