AMD – AGE-RELATED MACULAR DEGENERATION
What Is Age-Related Macular Degeneration?
The most common cause of vision loss in people over the age of 50 is age-related macular degeneration, or “AMD”. The macula is a small, specialized area in the back of your eye that allows you to see fine detail. As some people age, this macular area may degenerate, affecting your central vision. Things that require seeing fine detail – such as reading, telling time, driving, or even recognizing faces – becomes harder, while your peripheral vision remains intact. There are two type of macular degeneration – “dry” and “wet”.
90% of macular degeneration cases are dry AMD. Dry AMD is a less severe form and only accounts for 10-20% of cases of severe vision loss. In this form of AMD, the macular tissue is thinned due to oxidative damage and in some cases, yellowish-white deposits called drusen that impair the nutrient transport to the retina. Dry AMD visual loss is usually gradual and less severe. However, it is possible for it to progress to wet AMD, a more severe form.
10% of AMD cases are the “wet” type, which accounts for 80-90% of severe vision loss. This form of AMD is more severe because it involves abnormal blood vessel growth and fluid leakage underneath the retina. This process is more aggressive than dry AMD, and can lead to rapid and pronounced visual loss. Wet AMD may occur on its own, or may be preceded by dry AMD. In either case, early detection is key to help preserve your vision.
Risk Factors of Macular Degeneration
As a part of the body’s natural aging process, many people develop macular degeneration. Our body is in constant contact with oxygen, and over time free-radicals develop causing damage to certain cells. This is called oxidative stress, which is thought to play a major role in the development of AMD. Another risk factor may involve abnormal cholesterol levels. Many people can develop drusen deposits under their retina. If these deposits accumulate near the macula and grow in size, this can lead to AMD development. Some risk factors are preventable, while others may be out of your control.
Some Important Risk Factors:
- Age – risk greatly increases over age 50
- Hereditary factors – up to 3 times greater risk within families
- Gender – females are more susceptible
- Systemic factors – ex. cigarette smoking, cardiovascular disease, obesity, & high blood pressure
- Diet – a diet low in antioxidants, vitamins, and minerals
- Environmental factors – excess sunlight exposure & oxidative stress
Macular Degeneration Symptoms
Depending on the severity of the disease and whether or not it affects both eyes, the symptoms of AMD can vary from person to person. AMD affects your central vision, so some noticeable symptoms may include a dark or empty area in the center of your vision, or words on a page being blurred. Visual loss may be slow and painless, or your good eye may compensate for you bad eye, making it sometimes difficult to detect in early stages. On the other hand, wet AMD may cause severe and quickly progressive visual loss. A good way to monitor for symptoms is by using an amsler grid.
An Amsler grid is a simple way to detect early stages of AMD through changes in your central vision.
How To Use:
- Wear your reading glasses
- Hold grid at a comfortable reading distance, and in good light
- Cover one eye, and look directly at the center dot with the uncovered eye
- Note any distorted, blurred, or dark patches of lines
- Repeat with your other eye
- If any new areas of the grid looks wavy, blurry, or dark, contact your ophthalmologist immediately.
Diagnosis of Macular Degeneration
Many people may not realize the have AMD until the condition worsens to the point in which blurred vision becomes obvious. Thus, it is important to have regular medical eye exams to detect any early stages, as early detection is key to prevent or delay vision loss. Your ophthalmologist can detect symptoms through a simple amsler grid test, by looking at your macula through specialized lenses, or by having photographs taken of your eye using fluorescein angiography and optical coherence tomography (OCT). Fluorescein angiography involves taking photos of your retinal blood vessels and any abnormal vessel growth, while they are illuminated with a special dye. OCT takes a scan of your retinal layers, so any abnormal blood vessel growth or leakage can be detected.
How is Macular Degeneration Treated?
There is no cure for AMD, but it is treatable and severe vision loss is possibly preventable through the use of nutritional supplements, anti-VEGF treatments, laser surgery, and PDT.
Studies have shown that 25% of those with AMD can decrease their risk of developing advanced stages and vision loss by taking specific combination antioxidant vitamin supplements:
- Vitamin C (500 mg)
- Vitamin E (400 iu)
- Beta Carotene (15 mg)
- Zinc (80 mg)
- Copper (2 mg)
As preventative measure or those with very early stages of AMD, supplements have not been shown to be beneficial. Vitamin supplements are not a cure for AMD and will not restore any lost vision. However, it has been shown that they have helped some people who have AMD maintain their vision and slow the progression of the disease.
It is important to consult with your ophthalmologist to find out if you are at risk for developing advanced AMD and whether or not you are a candidate for vitamin supplements. Studies have not revealed any evidence of adverse effects of treatment, although beta-carotene may increase the risk of lung cancer in those who smoke.
Some Other Beneficial Supplements:
- Folic acid
- Vitamins B6 & B12
- Fish oils
- Dark leafy greens & colorful fruits/vegetables (rich in lutein & zeazanthin)
Ant-VEGF Treatments, Laser Surgery, and PDT
Anti-VEGF injection is one of the most common ways of treating wet AMD. VEGF or vascular endothelial growth factor, is what causes the abnormal vascular growth underneath the retina in wet AMD. This injection targets and stops this specific chemical, to prevent further vessel growth and leakage, and thus the progression of wet AMD.
Another treatment option of some forms of wet AMD is Laser surgery. This is a brief outpatient procedure that uses a focused beam of light to target the specific leaking blood vessel.
Photodynamic therapy (PDT) uses a combination of these treatment options, using a special drug and laser treatment to stop and slow the leaking blood vessels.