RODS AFFECT S-CONE DISCRIMINATION ON THE FARNSWORTH-MUNSELL 100-HUE TEST

Rod influence on hue discrimination was assessed by the Farnsworth-Mun sell 100-hue test. Rod influence was taken as the difference in error scores obtained after complete dark adaptation and during the cone pla teau at three mesopic (23, 9, 3 td) and one standard (158 td) light le vel. On the FM 100, rods produced a differential discrimination loss a long a tritan axis as compared with a red-green axis without any bias toward a rod confusion axis. Rods appear to impair discrimination medi ated by S-cone pathways, which at moderate levels of illumination can differentially elevate tritan errors on the FM 100. (C) 1998 Elsevier Science Ltd. All rights reserved.