AMD

• Age-related macular degeneration (AMD)

  Affects macula (center of retina) and gradually destroys central (sharp) vision

  
• 1 in 7 Australians (~1.5 million) aged 50 and over have some level of AMD
• Early AMD


  No or minimal vision loss, difficulty in low light conditions
• Late AMD


  Vision loss; can be dry (geographic) or wet (neovascular)
• Leading cause of severe vision loss and legal blindness in Australia, approximately 50% of blindness
• Healthy retina


  • Retina with unhealthy macula
• Dry AMD


  More common form of late AMD, and develops slowly (years or decades)
• Wet AMD


  Abnormal blood vessel growth under the macula
• AMD Risk Factors


  • Age
  • Family history/genetics
  • Cigarette smoking
  • Diet and lifestyle
• Age


  Incidence of 0.3 per 1000 in those aged 55 to 59 years, 5.7 per 1000 in those aged 75 to 79 years, and 36.7 per 1000 in those aged 90 years or older
• Family history/genetics


  Genetic factors explain 46% to 71% of the variation in overall severity of AMD. The CFH and ARMS2-HTRA1are strongly linked to AMD
• Cigarette smoking


  Most consistently reported environmental risk factor for AMD
• Diet and lifestyle


  Eating patterns, nutritional supplements, physical activity are associated with AMD
• Diagnosis of AMD


  • Retinal photographs
  • Fluorescein angiogram
  • Optical coherence tomography (OCT)
  • Amsler grid
• Retinal photographs


  Provide a detailed image of the retina and a basis for comparison for future eye examinations

  
• Fluorescein angiogram


  Fluorescein dye injected through a vein in the arm. The dye rapidly reaches the eye and circulates through the retina to highlight any abnormalities

  
• Optical coherence tomography (OCT)


  Now a standard procedure in the diagnosis and management of wet AMD
• Amsler grid


  Used for diagnosis of AMD
• Treatment for Wet AMD


  1. VEGF (Vascular Endothelial Growth Factor) protein causes leaking and growth of new blood vessels

  2. Anti-VEGFs (e.g. Lucentis, Eylea, Beovu, Vabysmo) injected into the eye to block VEGF proteins

  3. Reduction in leaks, and growth of new blood vessels
• Dry AMD treatment


  US FDA approved intravitreal injections (pegcetacoplan and avacincaptad pego) inhibit steps in the complement pathway (immune system)
• Modifiable risk factors


  Smoking, diet and lifestyle
• Smoking cessation shown to reduce risk of AMD
• Convincing evidence that supplements containing beta-carotene increase lung cancer risk in smokers
• Cancer Council Australia recommends avoiding high dose (>18mg) beta-carotene supplementation, esp. in smokers
• Clinical trial


  1. Increase in dark green leafy vegetables

  2. Increase in legumes

  3. Decrease in processed/prepared food
• Key nutrients


  • Lutein (and zeaxanthin), nitrates: green leafy vegetables
  • Vitamin C, flavanones: fruit
  • Vitamin E, low GI: wholegrains, legumes
  • Long-chain omega-3 polyunsaturated fatty acids: fish, eggs
• Dietary patterns ? Mediterranean diet patterns
• Antioxidants


  Important for healthy cell function (decrease oxygenation of the polyunsaturated fatty acids)
• Macula


  Concentrated in carotenoids: lutein and zeaxanthin (and reduces amyloid-beta plaques)
• Nitrates


  May assist with vasodilation of micro-blood vessels in the eye

  
• Zinc


  Co-factor for antioxidant enzymes: superoxide dismutase and catalase
• Lutein and zeaxanthin intake in highest tertile had 65% lower risk of AMD compared to lowest tertile
• Vegetable intake in highest tertile had 36% lower risk of AMD compared to lowest tertile
• Omega-3 fatty acid Docosahexanoic acid (DHA)


  Found in high concentrations in the human retina, particularly high in photoreceptor cells of the retina; frequently shed and high turnover requires renewal
• Polyunsaturated fatty acids


  • Increase oxygenation
• Nitrates in food


  May assist with vasodilation of micro-blood vessels in the eye
• Zinc


  A co-factor for antioxidant enzymes: superoxide dismutase and catalase
• Lutein and zeaxanthin


  Reduce risk of age-related macular degeneration by 65%
• Vegetables


  Reduce risk of age-related macular degeneration by 36%
• Omega-3 fatty acid Docosahexanoic acid (DHA)


  Found in high concentrations in the human retina, particularly in photoreceptor cells where it is frequently shed and requires renewal