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.
© 2002 Optical Society of America
(120.1840) Instrumentation, measurement, and metrology : Densitometers, reflectometers
(170.6510) Medical optics and biotechnology : Spectroscopy, tissue diagnostics
(330.4300) Vision, color, and visual optics : Vision system - noninvasive assessment
(330.4460) Vision, color, and visual optics : Ophthalmic optics and devices
(330.5310) Vision, color, and visual optics : Vision - photoreceptors
Niels P. A. Zagers, Jan van de Kraats, Tos T. J. M. Berendschot, and Dirk van Norren, "Simultaneous Measurement of Foveal Spectral Reflectance and Cone-Photoreceptor Directionality," Appl. Opt. 41, 4686-4696 (2002)