Rod or cone dysfunction: uniocular presentations.

Two patients presented with unusual uniocular electroretinographic (ERG) phenomena. One patient showed the ERG characteristics of stationary night blindness in one eye only and the other patient presented with ERG evidence of uniocular cone dysfunction. In both patients, however, further electrophysiological and psychophysical studies and serial testing provided evidence for dysfunction of both receptor systems and relatively subtle involvement of the fellow eyes.