Fluorescence lifetime imaging ophthalmoscopy and the influence of oral lutein/zeaxanthin supplementation on macular pigment (FLOS)- A pilot study

Background & aims: Oral lutein (L) and zeaxanthin (Z) supplementation enhances macular pigment optical density (MPOD) and plays a protective role in the development of age-related macular degen-eration (AMD). Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a novel in vivo retinal imaging method that has been shown to correlate to classical MPOD measurements and might contribute to a metabolic mapping of the retina in the future. Our aim was to show that oral supplementation of L and Z affects the FLIO signal in a positive way in patients with AMD. Methods: This was a prospective, single center, open label cohort study. Patients with early and inter -mediate AMD received oral L and Z supplementation during three months, and were observed for another three months after therapy termination. All visits included measurements of clinical parameters, serum L and Z concentration, MPOD measurements using heterochromatic flicker photometry, dual wavelength autofluorescence imaging, and FLIO. Correlation analysis between FLIO and MPOD were performed.Results: Twenty-one patients completed the follow up period. Serum L and Z concentrations significantly increased during supplementation (mean difference 244.8 ng/ml; 95% CI: 81.26-419.9, and 77.1 ng/ml; 95% CI: 5.3-52.0, respectively). Mean MPOD units significantly increased (mean difference 0.06; 95% CI: 0.02-0.09; at 0.5 & DEG;, 202; 95% CI: 58-345; at 2 & DEG;, 1033; 95% CI: 288-1668; at 9 & DEG; of eccentricity, respec-tively) after three months of supplementation with macular xanthophylls, which included L and Z. Median FLIO lifetimes in the foveal center significantly decreased from 277.3 ps (interquartile range 230.2-339.1) to 261.0 ps (interquartile range 231.4-334.4, p = 0.027). All parameters returned to near -normal values after termination of the nutritional supplementation. A significant negative correlation was found between FLIO and MPOD (r2 = 0.57, p < 0.0001).Conclusions: FLIO is able to detect subtle changes in MPOD after L and Z supplementation in patients with early and intermediate AMD. Our findings confirm the previous described negative correlation between FLIO and MPOD. Macular xanthophylls seem to contribute to short foveal lifetimes. This study is registered at ClinicalTrials.gov (identifier number NCT04761341).& COPY; 2023 The Author(s). Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism. This is an open access article under the CC BY license (http://creativecommons.org/licenses/ by/4.0/).

Automated summary

The aim of this study was to investigate the effect of oral lutein and zeaxanthin supplementation on FLIO signal in patients with early and intermediate age-related macular degeneration (AMD). The results showed that lutein and zeaxanthin supplementation can improve MPOD and decrease FLIO lifetimes in the foveal center, confirming the negative correlation between FLIO and MPOD.