The association of retinal structure and macular pigment distribution

Macular pigment optical density (MPOD) and age-related macular degeneration (AMD) are thought to be associated; however, the details are not yet understood clearly. This study aimed at investigating how retinal anatomic structures relate with the spatial MPOD distribution in single eyes.

In a subgroup of the third follow-up examination of the Münster Aging and Retina Study (MARS) cohort (mean age, 78.4 years), 124 single eyes of 79 participants with early AMD were examined. The MPOD was assessed using 2-wavelength autofluorescence (AF). Retinal thickness (RT) and fovea pit profile slopes were measured using optical coherence tomography (OCT). The results were analyzed for interocular correlation in 58 pairs of eyes, and for the association of MPOD distribution patterns with RT using uni- and multivariate statistical methods.

The interocular correlations for several measures of RT and RT layers were high (P < 0.001). The RT was inversely and significantly related to MPOD at 1.0° and at 2.0° from the foveal center, but not to central MPOD. After controlling for sex, age, smoking, and spherical equivalent, RT was significantly thinner (-39.7 μm, P < 0.001) in eyes with ring-like compared to normal MPOD distribution. In particular, a thinner layer between internal and external limiting membrane showed strong associations with ring-like structures.

Higher values of MPOD at 1° and 2°, as well as a ring-like distribution of MPOD were associated significantly with thinner maculae, due to thinner inner retinal layers. The MPOD distribution was unrelated to the slope of the foveal pit or the choroidal thickness. Our results suggest that the retinal section between the internal and external limiting membrane is involved in the spatial distribution of MPOD.