Density of the Human Crystalline
Lens is related to the Macular Pigment
Carotenoids, Lutein and Zeaxanthin.
Authors:
Hammond BR Jr , Wooten BR , Snodderly DM
Vision Sciences Laboratory, College of Arts & Sciences, Arizona State University,
Phoenix, USA.
Optom Vis Sci 1997 Jul;74(7):499-504
PURPOSE: Although oxidative
stress may play an important role in the development of age-related cataract, the degree
of protection reported for antioxidant vitamins and carotenoids has been inconsistent
across studies. These varied results may be due in part to the lack of good biomarkers for
measuring the long-term nutritional status of the eye. The present experiments
investigated the relationship between retinal carotenoids (i.e., macular pigment), used as
a long-term measure of tissue carotenoids, and lens optical density, used as an indicator
of lens health.
METHODS: Macular pigment (460 nm) and lens (440, 500, and 550 nm) optical density were measured psychophysically in the same individuals. Groups of younger subjects--7 females (ages 24 to 36 years), and 5 males (ages 24 to 31 years)--were compared with older subjects--23 older females (ages 55 to 78 years), and 16 older males (ages 48 to 82 years).
RESULTS: Lens density (440
nm) increased as a function of age (r = 0.65,
p < 0.001), as expected. For the oldest group, a significant inverse relationship (y =
1.53-0.83x, r = -0.47, p < 0.001) was found between macular pigment density (440 nm)
and lens density (440 nm). No relationship was found for the youngest group (p 0.42).
CONCLUSIONS: The main finding of this study was an age-dependent, inverse relationship between macular pigment density and lens density. Macular pigment is composed of lutein and zeaxanthin, the only two carotenoids that have been identified in the human lens. Thus, an inverse relationship between these two variables suggests that lutein and zeaxanthin, or other dietary factors with which they are correlated, may retard age-related increases in lens density.
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