Abstract

Raman spectroscopy holds promise as a novel noninvasive technology for the quantification of the macular pigments (MP) lutein and zeaxanthin. These compounds, which are members of the carotenoid family, are thought to prevent or delay the onset of age-related macular degeneration, the leading cause of irreversible blindness in the elderly. It is highly likely that they achieve this protection through their function as optical filters and/or antioxidants. Using resonant excitation in the visible region, we measure and quantify the Raman signals that originate from the carbon double bond (C=C) stretch vibrations of the π-conjugated molecule backbone. In this manuscript we describe the construction and performance of a novel compact MP Raman instrument utilizing dielectric angle-tuned band-pass filters for wavelength selection and a single-channel photo-multiplier for the detection of MP Raman responses. MP concentration measurements are fast and accurate, as seen in our experiments with model eyes and living human eyes. The ease and rapidity of Raman MP measurements, the simplicity of the instrumentation, the high accuracy of the measurements, and the lack of significant systematic errors should make this technology attractive for widespread clinical research.

In vivo resonant Raman measurement of macular carotenoid pigments in the young and the aging human retina

Werner Gellermann, Igor V. Ermakov, Maia R. Ermakova, Robert W. McClane, Da-You Zhao, and Paul S. Bernstein
J. Opt. Soc. Am. A 19(6) 1172-1186 (2002)

Resonant Raman detection of macular pigment levels in the living human retina

Igor V. Ermakov, Robert W. McClane, Werner Gellermann, and Paul S. Bernstein
Opt. Lett. 26(4) 202-204 (2001)

Resonance Raman imaging of macular pigment distributions in the human retina

Mohsen Sharifzadeh, Da-You Zhao, Paul S. Bernstein, and Werner Gellermann
J. Opt. Soc. Am. A 25(4) 947-957 (2008)

Raman imaging of human macular pigments

Werner Gellermann, Igor V. Ermakov, Robert W. McClane, and Paul S. Bernstein
Opt. Lett. 27(10) 833-835 (2002)

Nonmydriatic fluorescence-based quantitative imaging of human macular pigment distributions

Mohsen Sharifzadeh, Paul S. Bernstein, and Werner Gellermann
J. Opt. Soc. Am. A 23(10) 2373-2387 (2006)