Age-Related Macular Degeneration (AMD) Defined AMD= disease associated with aging that gradually destroy sharp, central vision. AMD can advance so slowly that people notice little change in their vision. In others, it can progresses much faster and may lead to a loss of vision in both eyes. Two types: Dry and Wet AMD
Dry AMD Occurs when the light-sensitive cells in the macular slowly breakdown, cause gradually blurring central vision. Three stages of dry AMD: 1- Early AMD: several small or medium-sized drusen. Patients have no symptoms. 2- Intermediate AMD: many medium-sized or one or more large drusen. They can see a blurred spot in the center of their vision. 3- Advanced Dry AMD: in addition to drusen, patients have a breakdown of light sensitive cells, causing blurred spot in the center and getting bigger over time.
Wet AMD WetMD occurs when abnormal blood vessels behind the retina start to grow under the macular. These new blood vessels tend to be very fragile and often leak blood and fluid. The blood and fluid raise the macular from its normal place, causing macular edema. Lossof central vision occur quickly without treatment.
EpidemiologyThe Beaver Dam Eye Study: 30% individuals aged >75 have some form of AMD 7% of those have an advanced formRecent studies: 8 million Americans to be at risk of developing advanced AMD in the next 5 years
Epidemiology The cause of AMD remains unknown Mild association between hypertension and AMD Smokinghas been demonstrated to be the most consistence modifiable risk factors Greater levels of plasma vascular endothelial growth factor (VEGF), von Willebrand factor, and fibrinogen, as well as increased plasma viscosity, in patients with AMD
Treatment for Dry AMD Once dry AMD reaches the advanced stage, no treatment can prevent the vision loss. However, treatment can delay and possibly prevent intermediate AMD from progressing to the advanced stage. The National Eye Institute’s Age-Related Eye Disease Study (AREDS) : taking a specific high-dose formulation of antioxidants and zinc reduces the risk of advanced AMD.
INDICATION FOR AREDS Extensive intermediate drusen ( 64- 124 µm in diameter) At least one large drusen (≥ 125 µm in diameter) Noncentral geographic atrophy Advanced AMD in 1 eye
AREDS 2 Examine the effects of high supplemental doses of dietary xanthophylls ( 10 mg lutein and 2 mg zeaxanthin) and ω−3 LCPUFAs (DHA and EPA) on the development of advanced AMD. Results are likely to be announced in the second quarter of 2013
We Are What We Eat- Ho et al. analyzed the risk of early AMDin a cohort of 2167 individuals whose CFHand HTRA1 genotyping was known.( CFH Y402H variant : ↑ AMD risk 11x HTRA1 A69S allele: ↑ AMD risk 15x )- Increase intake of zinc, ᵦ-carotene, ω−3fatty acids and lutein/zeaxanthin eachsignificantly reduced the hazard ratio ofAMD development .
We Are What We EatOverall, the data suggest that weare not entirely at the mercy of ourgenes. A well-balanced dietincluding foods rich in zinc, ω−3fatty acids and antioxidants mightavert the genetic decree.