Abstract

The relative numbers of L and M cones were estimated at the fovea and at temporal 2°, 7°, 17°, and 28° and at nasal 2°, 7°, 28° eccentricity along the horizontal meridian in two color normal observers (methods of Cicerone and Nerger, 1989). Unique hues were also measured at these locations. The total cone density distributions are comparable to anatomical data (Curcio et al.,1990). The relative number of L and M cones remains constant at these eccentricities. One observer’s ratio of 2.00 falls within the range of 1.46 to 2.36 previously measured for nine observers (Cicerone, 1990). Unique yellow measured at the same locations was also constant (about 670 nm) with eccentricity. Another observer with a smaller L to M cone ratio has a unique yellow at a longer wavelength (about 580 nm). These results can be interpreted by assuming that the latter observer has relatively more M cones but has the same neural connections to the red–green opponent system.

© 1992 Optical Society of America