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Roy Schwartz, Roxanne Crosby-Nwaobi, Adam M Dubis, Philip G Hykin, Sobha Sivaprasad; The distribution of macular pigment in different macular diseases. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4818. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Macular pigment (MP) is mainly located in the photoreceptor axons but also to a lesser extent through the photoreceptor (PR) outer segments and inner retina. Its distribution has been studied in different macular diseases, but no comparison has been made between different diseases. In this prospective observational study we used dual wavelength autoflourscence (DWAF) to measure the distribution of MP in several diseases and examined its correlation with retinal layer thickness.
72 eyes of 37 patients aged 18 years or older with different macular diseases (central serous chorioretinopathy (CSC) (n=7), non-proliferative diabetic retinopathy (NPDR) (n=28), early and intermediate age-related macular degeneration (AMD) (n=18), advanced AMD (n=10)) and normal patients (n=9) were included in the study. The MP optical density (MPOD) was measured using DWAF at 0.5° and 2° eccentricities. MPOD measurements were examined for correlation with central foveal thickness (CFT). Additionally, MPOD at 0.5° was examined for correlation with the thickness of the outer nuclear layer, using a measurement from the outer plexiform/inner nuclear layer interface to the external limiting membrane (ONL+), and the thickness of the PR layer (external limiting membrane to RPE). These measurements were done at 150 µm from the center of the fovea, corresponding to 0.5°.
In all eyes, we found a correlation between MPOD and CFT at 0.5°, but not at 2° (p=0.02 and 0.07, respectively). MPOD at 0.5° was more closely correlated with the PR layer than the ONL when all eyes were compared (p=0.19 vs. p=0.9, respectively). However, that correlation varied among the different groups. For instance, NPDR (p=0.04 vs. p=0.8), advanced AMD (p=0.16 vs. 0.66) and normals (p=0.05 vs. 0.50) followed the trend. In contrast, earlier AMD (p=0.8 vs. p=0.2) and CSC (0.90 vs 0.74) showed the opposite relationship.
Our results show that more MP is found in retinas with a thicker photoreceptor layer, which lends evidence to MP’s neuroprotective effect. Our data suggests that in some diseases (NPDR, advanced AMD, and in normal patients) there was a stronger correlation between PR layer thickness and MPOD, while in others (early and intermediate AMD and CSC) the correlation was with ONL+. This may result from differences in disease pathology. Future work involving more precise segmentation and more subjects may be needed to improve analysis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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