Abstract
Abstract: :
Purpose: The macular pigments lutein and zeaxanthin may be of fundamental importance in the treatment and prevention of age-related macular degeneration, the leading cause of blindness in the elderly. Non-invasive optical techniques are needed to map the spatial distributions of these pigments. Methods: We have imaged the spatial distribution of macular carotenoid pigments in the human retina employing Resonance Raman spectroscopy. Using excised eyecups as initial test samples and resonant excitation of the pigments with narrow bandwidth blue light, we record Raman images originating from the carbon-carbon double bond stretch vibrations of the pigment molecules. Results: We observe Raman images in eyecups with widely varying macular carotenoid pigment concentrations. The images provide micron-scale spatial information on the carotenoid distribution as well as quantification of the carotenoid levels. Most significantly, the Raman images reveal pronounced individual differences in the spatial distribution of carotenoids, including varying peak heights, rotational asymmetries and other topological features. Conclusion: Resonance Raman spectroscopy holds promise for a novel noninvasive optical imaging technology for rapid screening of macular carotenoid pigments in large populations at risk for vision loss from age related macular degeneration.
Keywords: 337 carotenoids/carotenoid binding proteins • 356 clinical (human) or epidemiologic studies: systems/equipment/techniques • 310 aging: visual performance