Changes following supplementation with lutein and zeaxanthin in retinal function in eyes with early age-related macular degeneration: a randomised, double-blind, placebo-controlled trial

Randomized, double-blind, placebo-controlled trial in adults with early age-related macular degeneration recruited in Beijing, China. Active intervention arms included 10 mg lutein, 20 mg lutein, and lutein 10 mg plus zeaxanthin 10 mg.

Participants received oral capsules for 2 years containing 10 mg lutein daily, 20 mg lutein daily, or lutein 10 mg plus zeaxanthin 10 mg daily, compared with placebo. Capsules were identical in appearance.

Supplementation increased macular pigment optical density (MPOD) in the active groups, and lutein improved retinal sensitivity. MPOD rose significantly in active arms, with values at 2 years of 0.442±0.127 for 10 mg lutein, 0.441±0.133 for 20 mg lutein, and 0.383±0.149 for lutein plus zeaxanthin. At 2 years, macular retinal sensitivity at 1° eccentricity was higher than placebo (10.32 dB) in the 10 mg lutein group (13.37 dB) and 20 mg lutein group (12.55 dB), with p<0.05. The 20 mg lutein group also showed a 32.8% increase in ring 2 density at 48 weeks (p<0.05), while rings 3-6 did not change significantly. No adverse events were observed or reported.

The trial had modest per-arm sample sizes and was conducted at a single center in Beijing, which limits generalizability. Ethnicity was not reported, and some retinal function changes were limited to select eccentricities or rings rather than being uniform across all measures. The active-arm counts reported across source fields are slightly inconsistent, which adds uncertainty to exact per-arm denominators.