Retinal Ageing Clinical Trial
Official title:
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.
It is believed that the macular pigment protects the retina against photooxidative damage
which can lead to agerelated macular degeneration (AMD). It is also hypothesized to enhance
visual performance in normal human eyes. Much of the research into lutein supplementation
has been centered around AMD subjects. AMD can result from agerelated retinal photoreceptor
dysfunction which could hypothetically be prevented or slowed down through early
supplementation. To our knowledge, the effects of lutein in normal ageing, have not been
studied previously.
Macular pigment is composed of lutein and zeaxanthin. These compounds absorb blue light and
therefore protect the retinal photoreceptors. They also possess powerful antioxidant
properties and therefore help maintain the integrity of the macular region. With increasing
age, the visual performance worsens as a result of preretinal and retinal changes such as
photoreceptor degeneration. Rods (responsible for night vision) are highly susceptible to
degeneration in a normal aging eye and in AMD. Older subjects often complain of reduced
vision in the dark which can contribute to increased risk of road traffic accidents and
falls. Since the older population is rapidly growing, it is vital to study the mechanics of
photoreceptor degeneration and the possible beneficial effects of supplementation with
retinal carotenoids, particularly lutein.
The supplement that will be used in this study will be the commercially available Visionace
Plus (details attached). The manufacturer of Visionace Plus is Vitabiotics. The placebo will
be soya-based, also manufactured by Vitabiotics.
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Allocation: Randomized, Endpoint Classification: Bio-availability Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention