Macular pigment optical density linked to visual function

In healthy eyes, macular pigment optical density (MPOD) correlates with parameters of visual function such as photostress recovery, contrast sensitivity (CS), and glare disability, a recent meta-analysis has found.

From the databases of Medline, Cochrane, and the Commonwealth of Agriculture Bureau, the researchers retrieved 22 publications that looked at the link between MPOD and visual function in healthy adult eyes. Case-control studies, case reports, and reviews were ineligible. Random effects model meta-analyses were performed to obtain study-level correlations.

Synthesis of two studies (n=209 participants) indicated a significant correlation between CS and MPOD measured at 30’ eccentricity (summary r, 0.37, 95 percent confidence interval [CI], 0.15–0.56). Heterogeneity of evidence was moderate. In three other studies, CS also showed significant association with MPOD measured at 1° eccentricity with spatial frequencies of 7, 11, and 12 cpd.

In terms of photostress recovery, two studies (n=176 participants) measured MPOD at 1° eccentricity and found a significant random effects correlation at 10 cpd, 16 percent contrast, and moderate background (summary change, –0.17, 95 percent CI, –0.31 to –0.02).

Four other studies found that MPOD at a 30’ eccentricity was negatively but significantly correlated with photostress recovery (summary change, –0.57, 95 percent CI, –0.78 to –0.24).

Glare disability was likewise correlated with MPOD, as measured at 30’ eccentricity in three studies that looked at the log scale of glare disability at 460 nm (summary r, 0.47, 95 percent CI, 0.32–0.59).

“Our evaluation suggests that higher MPOD may be beneficial for visual function. This may be due to lutein and zeaxanthin’s role as antioxidants,” the researchers said. “Although the precise mechanisms by which lutein and zeaxanthin may be influencing neural health remain to be investigated, efforts may be warranted to establish recommended intakes for these dietary carotenoids.”