Abstract
Purpose: :
Carotenoids protect human tissues and DNA from oxidative stress. Of the 14 carotenoids detected in human, only lutein and zeaxanthin, along with their metabolites, are found at the highest concentration in the macula. We investigated the relationship between macular pigment optical density and foveal volume, and the effect of age and ethnicity on this relationship.
Methods: :
Prospective observational study of the right eye of twenty-nine healthy subjects with normal macula. Macular pigment optical densities (MPOD) were measured by heterochromatic flicker photometry at 15 min and 30 min retinal eccentricities. Foveal volume (FV) was determined using three-dimensional reconstructed image of the macula obtained using a laboratory prototype high-resolution Fourier-domain optical coherence tomography system.
Results: :
The mean ± SD MPOD was 0.59±0.05 (range from 0.21 to 1.12) at 15 min eccentricity and 0.50±0.053 (range from 0.17 to 1.00) at 30 min eccentricity. Mean MPOD measured at 15 and 30 min (mean MPOD) was not significantly related to FV measured at 30 min (r = 0.352, p=0.061) among the 29 subjects. Among non-Caucasians (n = 17), mean MPOD was significantly related to FV measured at 30 min (r = 0.5933, p=0.0121). However, mean MPOD was unrelated to FV at 30 min among Caucasians (n = 12, r = 0.221, p = 0.4893). When analyzed based on age, the relationship between mean MPOD and FV at 30 min was significant among subjects < 50 years of age (n = 18, r = 0.502, p = 0.0338). The correlation between mean MPOD and FV at 30 min among subjects with age 50 or greater was weaker and reached only borderline significance (n = 11, r = 0.593, p = 0.0543).
Conclusions: :
A weaker correlation between MPOD and foveal volume was noted among normal subjects with known risk factors for age-related macular degeneration (AMD), i.e. Caucasian race and older age. The implication of this observation on our understanding of pathogenesis of AMD needs to be further explored.
Keywords: imaging/image analysis: non-clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • carotenoids/carotenoid binding proteins