What is macular degeneration?
The retina is a layer of nerve cells that lines the inside of the eye and enables the eye to see images, and the macula is the central portion of the retina, is important for seeing fine detail, reading and driving. Macular degeneration is caused by the deterioration of the macula, and vision can become distorted or blurry. In early stages, macular degeneration may not affect vision, however, if the condition progresses, those affected can experience blurred or distorted vision. Macular degeneration is a progressive condition, and if it continues to worsen, central vision may be completely lost. In cases of advanced macular degeneration, the retina is still functional, but only peripheral vision is retained. The vision loss in macular degeneration is painless. There are two forms of the condition: dry and wet.
What is the difference between dry and wet macular degeneration?
Dry age-related macular degeneration is the most common type, which makes up approximately 85% to 90% of cases of macular degeneration. It occurs when the tissue of the macula gradually becomes thin, and functions less as it progresses. This is due to formation of small, yellow deposits of fat and protein build-up under the macula, known as drusen. Dry AMD becomes progressively worse over the years, and there are minimal symptoms and gradual loss of central vision.
Wet AMD is a more advanced form of the condition and causes vision loss when abnormal blood vessels (known as choroidal neovascularization or CNV) grow under the retina and macula. These blood vessels may then bleed and leak fluid, causing the macula to bulge or lift it from its normally flat position, thus distorting central vision due to scar tissue formation. Unlike the dry form, wet AMD can progress rapidly and cause vision loss over the course of days to weeks. Early detection and treatment of wet AMD may help reduce vision loss, and in some cases, recover some vision.
What is the treatment for macular degeneration?
Currently, there is no treatment for dry macular degeneration. Typically, it progresses at a slower rate than that of the wet form, but can sometimes become the wet age-related macular degeneration. For this reason, regular eye examinations and home testing/monitoring using an Amsler grid are important for those with dry AMD. Additionally, the regular intake of vitamin supplements can decrease the risk of severe vision loss due to macular degeneration. Investigation and trials from a research program called Age-Related Eye Disease Study (AREDS), published by the National Institutes of Health (NIH), found that taking high levels of antioxidants and zinc have reduced the risk of developing wet AMD by 25%.
The current vitamin and doses per day based on the AREDS 2 formulation, are listed below
- Vitamin C (500 mg)
- Vitamin E (400 IU)
- Zinc (25 mg)
- Copper (2 mg)
- Bilberry Fruit Extract (50 mg)
- Lutein (10 mg)
- Zeaxanthin (2 mg)
As for wet age-related macular degeneration, injections of medications (Avastin, Lucentis) can counteract the growth and leakage of abnormal blood vessels, and therefore prevent severe vision loss, and in some cases, have a significant gain in vision with continued treatment. Additionally, laser photocoagulation and photodynamic therapy(?) can also be used in conjunction with injection therapy. The frequency for these treatments will vary from case to case, and a customized treatment plan will be developed for every patient according to their condition.