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Journal of Biomedical Optics • Open Access

Directional and nondirectional spectral reflection from the human fovea
Author(s): Jan van de Kraats; Dirk van Norren

Paper Abstract

A model of the directional and nondirectional reflection spectrum of the human fovea is developed, incorporating reflectors, absorbers, and a wavelength-dependent optical Stiles-Crawford effect (OSCE). Data from 102 healthy subjects between 18 and 75 years obtained with the fundus reflection analyzer (FRA), an imaging spectrograph that measures the directional reflection profile of the human fovea in the pupil plane from 400 to 950 nm, were analyzed. Subgroups of young (<40 years) and old (>50 years) observers were defined. Mean results of the young group defined a template for directionality versus wavelength. For the whole group, mean reflection at 550 nm from the cones was 2.12%, from the retinal pigment epithelium 0.56%, and from the choroid 7.92%. Lens density, cone disc reflection, and blood layer thickness showed significant trends versus age. The model for the first time simultaneously describes the spectra of the directional and nondirectional reflection of the human fovea. Rayleigh scatter losses of the media and in preretinal layers were assumed zero in the nondirectional pathway. Mean density of the macular pigment of a subgroup (53 subjects, 19 to 75 years) correlated significantly with independent data from reflectance and autoflourescence images obtained by scanning laser ophthalmoscope (SLO) and data from flicker photometry.

Paper Details

Date Published: 1 March 2008
PDF: 13 pages
J. Biomed. Opt. 13(2) 024010 doi: 10.1117/1.2899151
Published in: Journal of Biomedical Optics Volume 13, Issue 2
Show Author Affiliations
Jan van de Kraats, Univ. Medisch Ctr. Utrecht (Netherlands)
Dirk van Norren, Univ. Medisch Ctr. Utrecht (Netherlands)

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