We compared the spatial distribution of short-wavelength-sensitive (SWS or blue) cone photoreceptors in the retinas of eight primate species. The regularity of the SWS cone array was quantified with a statistic (packing factor) that varies between a random distribution (0) and a triangular array (1). We find wide variability among species, with packing factors varying between 0.06 and 0.3. The SWS cone array in at least two New World monkey species is indistinguishable from a random array. The SWS cone density gradient across the retina was measured in the capuchin monkey <i>Cebus apella</i> and the squirrel monkey <i>Saimiri sciureus</i>. Both species show a peak density of 5000–8000 cells/mm<sup>2</sup> at the fovea and a 50-fold central–peripheral density gradient. In contrast to the wide variation in local regularity, the spatial density and the topography of SWS cones are well preserved across primates.
© 2000 Optical Society of America
(330.1070) Vision, color, and visual optics : Vision - acuity
(330.1690) Vision, color, and visual optics : Color
(330.5310) Vision, color, and visual optics : Vision - photoreceptors
(330.7310) Vision, color, and visual optics : Vision
Paul R. Martin, Ulrike Grünert, Tricia L. Chan, and Keely Bumsted, "Spatial order in short-wavelength-sensitive cone photoreceptors: a comparative study of the primate retina," J. Opt. Soc. Am. A 17, 557-567 (2000)