title: In vivo resonant Raman measurement of macular carotenoid pigments in the young and the aging human retina.
abstract: We have used resonant Raman scattering spectroscopy as a novel, noninvasive, in vivo optical technique to measure the concentration of the macular carotenoid pigments lutein and zeaxanthin in the living human retina of young and elderly adults. Using a backscattering geometry and resonant molecular excitation in the visible wavelength range, we measure the Raman signals originating from the single- and double-bond stretch vibrations of the pi-conjugated molecule's carbon backbone. The Raman signals scale linearly with carotenoid content, and the required laser excitation is well below safety limits for macular exposure. Furthermore, the signals decline significantly with increasing age in normal eyes. The Raman technique is objective and quantitative and may lead to a new method for rapid screening of carotenoid pigment levels in large populations at risk for vision loss from age-related macular degeneration, the leading cause of blindness in the elderly in the United States.
authors.affiliation: Department of Physics and Dixon Laser Institute, University of Utah, Salt Lake City 84112, USA. werner@physics.utah.edu
authors.forename: Werner
authors.initials: W
authors.lastname: Gellermann
authors.forename: Igor V
authors.initials: IV
authors.lastname: Ermakov
authors.forename: Maia R
authors.initials: MR
authors.lastname: Ermakova
authors.forename: Robert W
authors.initials: RW
authors.lastname: McClane
authors.forename: Da-You
authors.initials: DY
authors.lastname: Zhao
authors.forename: Paul S
authors.initials: PS
authors.lastname: Bernstein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002338:Carotenoids / Q000378:metabolism*; D006801:Humans; D008266:Macula Lutea / Q000378:metabolism*; D008875:Middle Aged; D011323:Primates / Q000378:metabolism; D012016:Reference Values; D012160:Retina / Q000378:metabolism; D012168:Retinal Pigments / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000295:instrumentation
chemical_list: D012168:Retinal Pigments; D002338:Carotenoids