Clinical
studies of carotenoid macular pigments (MP) have been limited by
the lack of noninvasive, objective instruments. We introduce a novel
noninvasive optical instrument, an MP Raman detector, for assessment of
the carotenoid status of the human retina
in vivo. The
instrument uses resonant excitation of carotenoid molecules in the visible
wavelength range, and quantitatively measures the highly specific Raman signals
that originate from the single- and double-bond stretch vibrations of
the

-conjugated carotenoid molecule's carbon backbone. The instrument is a
robust, compact device and suitable for routine measurements of MP
concentrations in a clinical setting. We characterized and tested the
instrument in clinical studies of human subjects to validate its
function and to begin to establish its role as a
possible screening test for macular pathologies. We also show that
the MP Raman spectroscopy technology has potential as a novel,
highly specific method for rapid screening of carotenoid antioxidant levels
in large populations at risk for vision loss from age-related
macular degeneration, the leading cause of blindness of the elderly
in the developed world.
©
2004 Society of Photo-Optical Instrumentation Engineers.