Age-related Macular Degeneration (AMD)
Macular Degeneration or Age-related macular degeneration (AMD) is an eye disease that can blur the central vision. AMD is a common condition and a leading cause of vision loss for people age 50 and older. AMD doesn’t cause complete blindness, but impaired central vision can make it harder to see faces, read and drive.
- Impaired Central Vision
- Blurred area near the center of vision
- Straight lines appear crooked
- A blind spot in the center of vision
- Change in color perception
You may start noticing colors, such as yellow, purple and pastels turn into shades of black and gray. As damage to the macula progresses, all color recognition can be affected.
- Difficulty seeing in low light
You may notice that you have become more sensitive to light and it may take longer for you to adjust your vision to areas with dimmed light, especially after being in an area with brighter light, for example, returning to a dark room after being outside.
- Nearby objects seem far away
You may notice that nearby objects appear like they are further away because you sense that objects are smaller than they actually are. This can affect reading, facial recognition, and driving.
Risk of AMD
- Over age 60
- Have a family history of AMD
- Are Caucasian
How Do you lower the risk
- Quit smoking or don’t start
- Get regular exercise
- Maintain a healthy blood pressure and cholesterol levels
- Keep a healthy diet, including leafy green vegetables and fish
Stages of AMD
Early AMD is diagnosed by the presence of a lot of small fatty deposit called drusen, several middle-sized drusen or bigger areas of abnormal color change. People with early AMD typically do not have vision loss.
People with intermediate AMD typically have large drusen, pigment changes in the retina, or both. Intermediate AMD may cause some vision loss, but most people will not experience any symptoms.
In addition to drusen, people with Advanced AMD have vision loss from damage to the macula.
There are two types of Advanced AMD:
In dry AMD, light-sensitive cells in the macula slowly break down causing vision loss.
In wet AMD, abnormal blood vessels grow underneath the retina. These vessels often leak fluid and blood, which may lead to swelling and damage of the macula. Wet AMD damages the macular more rapidly and severely.
Age-Related Eye Disease Study (AREDS and AREDS 2)
The Age-Related Eye Disease Study (AREDS) was clinical trial sponsored by the National Eye Institute (NEI) between 1992 and 2001. The AREDS was designed to learn more about the natural history and risk factors of age-related macular degeneration (AMD) and cataract and to evaluate the effect of high doses of vitamin C, vitamin E, beta-carotene and zinc on the progression of AMD and cataract. The study followed 3,640 individuals for an average of 6.3 years. The researchers concluded that high levels of antioxidants and zinc significantly (by about 25%) reduce the risk of advanced AMD and its associated vision loss. However, these same nutrients had no significant effect on the development or progression of cataract.
In 2006, scientists from NEI started a second study called AREDS2 to determine if AREDS formulation would be improved by adding Omega 3 fatty acids, substituting beta-carotene with Lutein and Zeaxanthin or reducing zinc. Beta-carotene had been associated with an increased risk of lung cancer in smokers in previous study.
In AREDS2, formulation variations the researchers have tested are:
- Adding the antioxidants lutein and zeaxanthin (10 mg and 2 mg)
- Adding omega-3 fatty acids (350 mg DHA and 650 mg EPA)
- Removing beta-carotene
- Lowering the dose of zinc (25 mg)
The AREDS2 trial found that adding lutein and zeaxanthin or omega-3 fatty acids to the original AREDS formulation (with beta-carotene) had no overall effect on the risk of late AMD. However, the trial also found that replacing beta-carotene with lutein and zeaxanthin may help further reduce the risk of late AMD for people that has very little dietary intake of lutein and zeaxanthin. Low dose of zinc at 25mg provided similar benefits to lower the risk of progression of advanced AMD.
What formulation should I take?
Below is the formulation recommended by NEI:
- 500 mg of vitamin C per day
- 400 IU of vitamin E per day
- 80 mg zinc per day
- 2 mg copper per day
- 10 mg lutein and 2 mg zeaxanthin per day
However, physicians and nutritionists expressed concerns of 80mg Zinc, which significantly exceeds that Recommended Daily Intake (RDI) of 11 mg for Adults and is twice the amount of the safe upper limit of 40 mg for adults. People with high intake of zinc may experience digestive issues such as vomiting, cramping, nausea, diarrhea and headaches. Many physicians and nutritionists recommended to take AREDS 2 formulations with 25mg zinc per day.