a 2 degrees test stimulus foveally fixed and viewed against a blue background ( 40 degrees in extent and producing 2.0 x 10 ( 4 ) scotopic td of retinal illuminance ) evokes a small voltage which can be recorded from the human eye with a conventional contact lens electrode if the test stimulus is flashed at a rate of 15 c/s , and the responses to at least several hundred flashes are averaged.2 .
C0035298
retinal
C0015392
eye