The two major degenerative diseases of the eye, cataracts and AMD (Age Related Macular Degeneration) are now known to be strongly associated with progressive oxidative damage to the eye as ageing occurs.
Cataracts are the leading cause of visual impairment in older people and AMD is the leading cause of irreversible blindness. AMD affects the macular, which is part of the retina and is the site of highest visual acuity. Cataracts are characterized by opacification of the lens.
The association between the carotenoids lutein and zeaxanthin, and AMD is now clear:
- Lutein and zeaxanthin are the only carotenoids found in the macular and the lens
- These carotenoids appear to be present to prevent the peroxidation of long chained fatty acids, which form the basis of the ‘rod’ cell light receptors
- High intake of lutein and zeaxanthin correlate with high plasma concentrations of these two carotenoids. In human studies, this has been found to be associated with lowered risk of AMD and cataracts
- AMD and cataract suffers have low levels of lutein and zeaxanthin in their macular and lens tissues
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