title: Simultaneous measurement of foveal spectral reflectance and cone-photoreceptor directionality.
abstract: An instrument for simultaneous measurement of foveal spectral reflectance and cone-photoreceptor directionality is described. The key element is an imaging spectrograph (spectral range of 420-790 nm) with its entrance slit conjugate to the pupil plane of a human eye. A 1.9-deg spot on the retina is sampled in 1 s. Video observation of the retina and the pupil facilitates proper alignment. Measurements were performed on 21 healthy subjects. Model analysis of the spectra provided densities of photostable ocular absorbers. As an example, macular pigment and melanin are discussed in more detail. Spatial profiles exhibited the optical Stiles-Crawford effect, reflecting cone-photoreceptor directionality.
authors.affiliation: Department of Ophthalmology, University Medical Center Utrecht, The Netherlands. niels@isi.uu.nl
authors.forename: Niels P A
authors.initials: NP
authors.lastname: Zagers
authors.forename: Jan
authors.initials: J
authors.lastname: van de Kraats
authors.forename: Tos T J M
authors.initials: TT
authors.lastname: Berendschot
authors.forename: Dirk
authors.initials: D
authors.lastname: van Norren
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005584:Fovea Centralis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009885:Ophthalmology / Q000295:instrumentation*; D011680:Pupil; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012542:Scattering, Radiation