Macular carotenoid supplementation and visual function in early age-related macular degeneration

The carotenoids (lutein [L], zeaxanthin [Z] and meso-zeaxanthin [MZ]) are found at the macula, where they are collectively known as macular pigment (MP). The macula is a specialized part of the retina responsible for central vision. MP acts as a blue light filter, and its constituent carotenoids have antioxidant and anti-inflammatory properties. MP is believed to protect against progression of age-related macular degeneration (AMD), which is the leading cause of blindness in the developed world by protecting against oxidative stress. This PhD thesis answers three main research questions as follows: 1. what is the prevalence of AMD in the Republic of Ireland (ROI)? (research question 1); 2. what is the impact of supplementation using three different macular carotenoid formulations on MP and visual function in patients with non-advanced AMD over a three-year period? (research question 2); 3. Does the addition of MZ to the standard of care confer advantages or disadvantages to patients with non-advanced AMD in terms of visual outcomes and in terms of MP augmentation? (research question 3, main study). This thesis provides prevalence estimates of AMD in the ROI for the first time, and adds to the evidence with respect to the impact of macular carotenoid supplementation on visual function among patients with this condition.