Two years of supplementation with lutein and zeaxanthin may boost macular pigment optical density (MPOD) and retinal sensitivity in people with early age-related macular degeneration (AMD), says a new study.
Lutein and zeaxanthin are the only carotenoids capable of filtering the harmful blue light than can damage cells in the eye, the rods and the cones.
The carotenoids are concentrated in the macula, a yellow spot of about five milimeters on the retina. A thin macular pigment can allow the blue light through and destroy the cells. According to a 2010 review published in Vision Research macular pigment optical density (MPOD) -an indicator of xanthophyll levels in the eye- may also «potentially serve as a biomarker not only for predicting the risk for eye disease but also for visual function».
The new study, published in the British Journal of Ohpthalmology, found that lutein and zeaxanthin could booth MPOD in people with early AMD, and also enhance retinal sensitivity/function.
«Improvement in retinal function as a result of macular pigment
augmentation is probably attibutable ot al least one of two mechanisms,»
wrote reasearchers from Peking University. «First, pre-receptoral
filtration of blue light will attenuate the adverse effect of chromatic
aberration and of veiling luminance on contrast sensitivity. Second, the
antioxidant effect of macular carotenoids may exert a beneficial effect
in maculae afflicted with conditions known to result from oxidative
stress, such as AMD».