Abstract

Measurements of the relative numbers of the three cone types in human fovea centralis and parafovea are presented. The relative numbers of long-wavelength sensitive (L) to middle-wavelength sensitive (M) cones were estimated by applying a model which links the detection of a 1-min test to the number of cones contributing to detection in L cone isolating or M cone isolating conditions.¹ In fovea centralis, nine observers (1.46, 1.61, 1.99, 2.00, 2.05, 2.07, 2.28, 2.36, and 2.47) yield a mean value near 2 L cones for each M cone. The relative numbers of L and M cones remain constant from fovea centralis to 4° into the parafovea.

© 1989 Optical Society of America