The Bioavailability of Retinal Carotenoids in the Older Human Eye and Their Effects on Photoreceptor Performance

Normal ageing affects vision as a result of preretinal and retinal changes. Photoreceptors, the light sensitive cells in the retina, degenerate and the rods (responsible for night vision) are most susceptible to damage with increasing age. Rod loss leads to poor vision in the dark which increases the risk of accidents amongst the elderly. Macular pigment (located in the photoreceptors)is thought to protect the retina and reduce the risk of age related changes. Dark adaptation, mediated by the rods, slows down with age, and is also reduced in AMD (age-related macular degeneration). Recent evidence suggests that lutein (the main component of macular pigment) supplementation improves the dark adaptation deficit in AMD subjects. Research into the effects of lutein in a normal human has not been previously conducted. Since the older population is increasing, our aim is to firstly establish the extent of night vision loss (using dark adaptometry) and secondly to examine the possibility of slowing down or reversing this loss through lutein supplementation.