Abstract
Purpose :
Dual wavelength autofluorescence imaging (AFI) of macular carotenoid pigments facilitates rapid, reproducible quantification of nutritional status of the human retina, and resonance Raman spectroscopy (RRS) measurement of skin carotenoids is a validated, noninvasive biomarker of general nutritional status, particularly consumption of fruits and vegetables, but correlation of these two nutritional assessment modalities has not yet been established. We have undertaken a study to systematically compare these modalities to serum carotenoid levels in a clinic population.
Methods :
Subjects were recruited from retinal and general ophthalmology practices of a tertiary referral center and underwent evaluation of skin, macular, and serum carotenoid levels with IRB approval. Patients were excluded if they did not have all three modalities tested, had a diagnosis of macular telangiectasia (MacTel), or poor quality macular pigment scans, resulting in 31 participants included in this study. Macular pigmetn optical density (MPOD) at 0.5° and macular pigment volume under the curve (MPVUC) at 0.5° and 2.0° were measured by dual wavelength AFI on the Heidelberg Spectralis. Skin carotenoid levels were measured by RRS, and serum carotenoid concentrations were measured by HPLC. The data were then analyzed by linear regression with a p < 0.05 considered significant.
Results :
Skin RRS measurements of carotenoid levels correlated best with MPVUC at 2.0° (r2=0.19; p=0.013), while MPOD and MPVUC at 0.5° were less strongly associated with skin RRS (r2=0.14, p= 0.039; r2=0.123, p=0.053). Skin measurements significantly correlated with total serum carotenoid concentrations (r2=0.51; p < 0.0001), while macular correlations with serum carotenoids (total or lutein+zeaxanthin) were weaker and not significant (r2<0.1 and p>0.1).
Conclusions :
Our results emphasize the importance of measuring the total amount of carotenoids in the macular region (MPVUC) using an objective, imaging-based modality such as AFI rather than focusing on MPOD at just one or a limited number of eccentricities, as is commonly done with psychophysical methods. Skin RRS is a reasonable biomarker of macular carotenoid status that can be readily performed in a wide variety of research, clinical, and non-clinical settings.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.