The Central Retinal Enrichment Supplementation Trials ( CREST ) aim to investigate the potential impact of macular pigment ( MP ) enrichment , following supplementation with a formulation containing @mg lutein ( L ) , @mg zeaxanthin ( Z ) and @mg meso-zeaxanthin ( MZ ) , on visual function in normal subjects ( Trial @ ) and in subjects with early age-related macular degeneration ( AMD ; Trial @ ) .