Carotenoid Supplementation and Normal Ocular Health
Condition: Retinal Ageing
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): VisionAce; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Retinal ageing, macular pigment, visual function