While many individuals are able to convert provitamin A carotenoids, like beta carotene, into active vitamin A, recent research has revealed that genetic variations can limit the ease of this conversion for some. Genetic variations in the enzyme BCMO1 (?-Carotene 15,15'-monooxygenase 1) can decrease the conversion efficacy of carotenoids into retinal by up to 69%. Known as single nucleotide polymorphisms (SNPs), these common variations can be bypassed with dietary retinol (vitamin A). Since variations in the BCMO1 gene have also been associated with macular pigment density, this formula includes a blend of lutein, zeaxanthin and astaxanthin to promote macular health. Lutein and zeaxanthin are the two carotenoids found in macular pigment; as such, they act to support the integrity and density of the pigment, as well as optical lens health. Astaxanthin offers support for antioxidant defenses to protect retinal health.‡