Resonance Raman Spectroscopic Measurement of Macular Carotenoids in Japanese

Abstract

Abstract: : Purpose: The prevalence of age–related macular degeneration(AMD) is lower in non–white races than white. Atrophic AMD is low in Japanese, and some differences are found in clinical manifestations and therapeutic effects on even wet AMD between Caucasian and Japanese. Recently macular carotenoids have received considerable attention for their protective and therapeutic effects on AMD, and low carotenoid levels in the macula are considered a risk factor for AMD. In this study, we examined macular carotenoid levels and serum lutein levels in healthy Japanese using an objective optical method identical to one previously used in Caucasians. Methods: Macular carotenoid levels were measured by resonance Raman spectroscopy in 42 healthy volunteers free of any eye disease under the approval of the IRB in Maruyama Hospital. All subjects signed informed consent forms that complied with the tenets of the Declaration of Helsinki. Blood lutein levels were analyzed by HPLC. The subjects were 21 men and 21 women aged ranging from 20 to 71(41±18). Results: The mean of serum lutein levels were 206.4±78.7(SD) ng/ml. The level of macular carotenoids was 1264.8±576.4(SD) Raman counts. A wide variation of macular carotenoid levels was noted in younger subjects, while serum lutein levels varied most in elderly subjects. The average Raman counts declined with age, and values were comparable to that of a Caucasian population previously reported by Bernstein et al. There was no correlation between macular carotenoid and serum lutein levels. Conclusions: Macular carotenoid levels were measured objectively in Japanese for the first time. The tendency of macular Raman measurements to decline with age was similar to previously observed results in Caucasians. The comparison of carotenoid levels in different races is considered important for further understanding the pathogenesis of AMD.

Keywords: age-related macular degeneration • macular pigment • carotenoids/carotenoid binding proteins