Introduction
The Central Retinal Enrichment Supplementation Trials (CREST) were funded by a competitive grant from the European Research Council. These landmark studies were designed to assess whether supplementing with the three macular carotenoids, lutein, zeaxanthin, and meso-zeaxanthin, could deliver real, measurable benefits to visual function. This paper presents the findings from CREST AMD, a double-blind, placebo-controlled trial in patients with early age-related macular degeneration (AMD).
Why was the research undertaken?
While previous studies had shown that macular carotenoids could improve macular pigment and potentially visual performance, there was limited clinical trial evidence in real patients with AMD. Our goal here was to test whether supplementation could improve key visual outcomes, particularly contrast sensitivity, in a population already at risk of vision loss.
How was the study conducted?
121 patients with early AMD were randomised to receive either a daily supplement containing 10mg lutein, 10mg meso-zeaxanthin, and 2mg zeaxanthin, or a placebo, over a 24-month period. The primary outcome was contrast sensitivity, with additional outcomes including macular pigment optical density (MPOD), best corrected visual acuity (BCVA), and quality of life assessments.
What were the results?
The active group patients showed statistically significant improvements in how well they could see or detect contrast (contrast sensitivity) at several spatial frequencies, both at baseline and across the intervention period. Importantly, supplementation led to meaningful enrichment of the macular pigment and had a positive effect on measures of visual performance. These improvements were not observed in the placebo group.
What is the societal benefit?
This was the first randomised controlled trial to demonstrate that targeted carotenoid supplementation can benefit visual function in patients with early AMD. These findings support the clinical use of a three-carotenoid formulation in early disease management and highlight the importance of proactive, nutritional intervention in preserving vision and quality of life in an ageing population.
