Abstract
Purpose: :
Age–related maculopathy (ARM), which may damage central vision, is the leading cause of severe visual impairment in elderly white populations in the Western World. Although the aetiopathogenesis of this disease remains unclear, there is a growing, and plausible, consensus that cumulative blue light damage and/or oxidative stress play a role. Macular pigment (MP) is a blue light filter and a powerful antioxidant, and is therefore believed to protect against ARM. This study was undertaken to investigate the relationship between MP optical density (MPOD) and risk for ARM in 828 healthy subjects.
Methods: :
MPOD was measured psychophysically using heterochromatic flicker photometry. Clinical and personal details were recorded, with particular attention directed towards established and putative risk factors for ARM.
Results: :
We report a statically significant age–related decline in MPOD (Pearson correlation: r = – 0.286, p < 0.01), which persisted after correcting for known confounding variables [Partial correlation: r = – 0.245, p < 0.01]. Also, current and past smokers had lower average MPOD (mean ± SD) [0.268 (± 0.162) and 0.290 (± 0.166), respectively] than never smokers [0.315 (± 0.171)], and this difference was statistically significant (One–way ANOVA: p < 0.01). Finally, subjects with a confirmed family history of ARM had significantly lower levels of MPOD than subjects with no known family history of disease [0.219 (± 0.153) vs. 0.322 (± 0.166), respectively] (Independent samples t–test: p < 0.01)
Conclusions: :
In the absence of retinal pathology, the relative lack of MP associated with increasing age, tobacco use and family history of ARM supports the hypothesis that the macular carotenoids may be protective for this condition.
Keywords: macular pigment • age-related macular degeneration • oxidation/oxidative or free radical damage