Macular carotenoid supplementation improves disability glare performance and dynamics of photostress recovery

摘要

Background The so-called macular carotenoids (MC) lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) comprise the diet-derived macular pigment (MP). The purpose of this study was to determine effects of MC supplementation on the optical density of MP (MPOD), repeated-exposure photostress recovery (PSR), and disability glare (DG) thresholds. Methods This was a double-blind, placebo-controlled trial. Fifty-nine young (mean age?=?21.7), healthy volunteers participated in this study. Subjects supplemented their daily diet with either 10 mg L?+?2 mg total Z (1 mg Z?+?1 mg MZ; n =?24), 20 mg L?+?4 mg total Z (2 mg Z?+?2 mg MZ; n =?25), or placebo ( n =?10) for 12 months. The primary outcome was a composite measure of visual performance in glare, defined by change in DG and PSR. Secondary outcomes included MPOD and visual fatigue. The primary endpoint for outcomes was 12 months. MPOD was assessed with customized heterochromatic flicker photometry. PSR times for an 8 cycle /degree, 15 % contrast Gabor patch target were determined after each of five successive exposures to intense LED lights. DG threshold was defined as the intensity of a ring of lights through which subjects were able to maintain visibility of the aforementioned target. Measures of all parameters were conducted at baseline, 6 months, and 12 months. Repeated-measures ANOVA, and Pearson product-moment correlations were used to determine statistically significant correlations, and changes within and between groups. Results MPOD for subjects in both supplementation groups increased significantly versus placebo at both 6- and 12-month visits ( p