Macular pigment optical density relates to foveal thickness

Macular pigment is composed of 2 dietary carotenoids, lutein and zeaxanthin, and is mainly present at the nerve fiber layers and ganglion cell layers of the retina, with peak concentrations in the fovea. It is thought to function as a blue-light filter and antioxidant, and therefore protect the retina from damaging influences that are thought to play a role in the pathogenesis of age-related macular degeneration. This study was performed to investigate the suggested positive relationship between foveal macular pigment optical density (MPOD) and foveal retinal thickness.

We determined MPOD and foveal thickness in the right eyes of 40 healthy Caucasian subjects (5 men, 35 women) recruited at the University of Maastricht, The Netherlands. Their mean age was 24.4+/-8.7 years. MPOD was determined by using a novel method of heterochromatic flicker photometry (HFP), where subjects have to detect flicker instead of conventionally minimizing a present flicker motion. Foveal thickness parameters were obtained using optical coherence tomography (OCT 3).

We found a positively significant correlation between MPOD and central foveal thickness (r=0.359, p=0.027). In addition, we found a negatively significant correlation between foveal thickness and foveal width (r= -0.558, p<0.001).

Our data confirm the previously suggested positively significant correlation between MPOD and central foveal thickness. The observed negative relationship between foveal thickness and foveal width may be explained by eccentric scans on the OCT.