P 448 Blue on yellow full field flicker test

m. To establish a quick and easy test to examine flicker functions of the blue-sensitive pathway in a clinica: setting. Method. A strong steady orange adaptation light was used to suppress the red and green cones. Adaptation and stimulation lights were superimposed evenly in a ping-pang ball cut in half and placed close to the eye. This provided a large stimulus field (90 ") making fixation not critical. The spectral sensitivity (402-651 nm) of the response was determined by constructing flicker tision frequency (RI)-versus-hnninance functions at 100 % modulation (square-wave). From these functions spectral sensitivities were derived with two different criterional frequencies. Temporal contrast sensitivity curves of the blue-sensitive pathway were determined psychophysically by sinusoidally modulating a blue stimulus light (451 nnt) at different mean intensities of the stimulation (0.4-3.3 cdA+) and adaptation light (0-2700 cd/mz). Complete data were obtained from 3 nortnal subjects. &g&. In the fEversus-hnninance filnctions ST did not increase beyond 26 Hz in the blue. In the green and red the functions were steeper, were linearly related to log hnninance (Ferry-Porter law), and increased up to ca 60 Hz. The spectral sensitivity derived for a criterion of 15 Hz was dominated by a peak in the blue, for 44 Hz the sensitivity maximum was in the yellow. With increasing adaptation levels the temporal contrast sensitivity curves shit&d to lower frequencies (peak at 4 Hz) and to lower sensitivities indicating the isolation of the blue cones. With increasing stimulus levels the curves shifted to higher sensitivities with little shift along the frequency axis. Conc/usions. The results indicate thai the procedure described above isolates the blue cones. The examination at one frequency and at fixed hnninance levels may present a quick (10 mini test of the blue-sensitive system for clinical purposes e.g. for the examination of acquired dyschromatopsias (glaucoma).