title: Wavelength dependence of reflectometric cone photoreceptor directionality.
abstract: We present evidence for the wavelength dependence of the directionality of light reflected from cone receptor cells (optical Stiles-Crawford effect): Blue light is more directional than red. According to the waveguide-scattering model of Marcos et al. [J. Opt. Soc. Am. A 15, 2012 (1998)], directionality is the sum of a waveguide component and a scattering component. The latter is proportional to 1 over wavelength squared, and it is related to the row-to-row spacing of the cone lattice. Our results allow a firm confirmation of Marcos et al.'s theory. For a 1.9-deg foveal area, group mean (n = 18) cone spacing was 3.42 microm, in good agreement with anatomical data. Group mean waveguide directionality was 0.077 mm(-2).
authors.affiliation: Department of Ophthalmology, University Medical Center Utrecht, P.O. Box 85500, AZU E03.136, 3508 GA, Utrecht, The Netherlands. niels@isi.uu.nl
authors.forename: Niels P A
authors.initials: NP
authors.lastname: Zagers
authors.forename: Tos T J M
authors.initials: TT
authors.lastname: Berendschot
authors.forename: Dirk
authors.initials: D
authors.lastname: van Norren
mesh_terms: D006801:Humans; D008027:Light; D008954:Models, Biological; D011601:Psychophysics / Q000379:methods; D011680:Pupil / Q000528:radiation effects; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology* / Q000528:radiation effects*; D012542:Scattering, Radiation