Abstract
Abstract: :
Purpose: The macular pigments lutein and zeaxanthin may play an important role 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 to gain insight into macular pathology. Methods: We have developed Resonance Raman spectroscopy spectroscopy for rapid and quantitative imaging of the spatial distribution of macular pigments in the human retina. Using excised eyecups as initial test samples and resonant excitation of the pigments with mercury light or blue laser 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 pigments, including peak heights, rotational asymmetries and other topological features. Extension of the technology to the living human retina is being pursued employing rapid signal detection with a dual CCD camera arrangement. Conclusions: Resonance Raman spectroscopy holds promise for a novel noninvasive optical imaging technology for rapid screening of macular pigments in large populations at risk for vision loss from age-related macular degeneration.
Keywords: carotenoids/carotenoid binding proteins • clinical (human) or epidemiologic studies: sys • aging: visual performance