The Difference Between Wet and Dry Age-Related Macular Degeneration
There are two types of AMD: dry (atrophic) and wet (neovascular or exudative). Most AMD starts as the dry type and in 10-20% of individuals, it progresses to the wet type. Age-related macular degeneration is always bilateral (i.e., occurs in both eyes), but does not necessarily progress at the same pace in both eyes. It is therefore possible to experience the wet type in one eye and the dry type in the other.
Dry Macular Degeneration
The dry (atrophic) type affects approximately 80-90% of individuals with AMD. Its cause is unknown, it tends to progress more slowly than the wet type, and there is not—as of yet—an approved treatment or cure. In dry age-related macular degeneration, small white or yellowish deposits, called drusen, form on the retina, beneath the macula, causing it to deteriorate or degenerate over time.
You can read more at What Treatments Are Available for Dry Macular Degeneration?
Wet Macular Degeneration
The wet/neovascular type affects approximately 10-15% of individuals with age-related macular degeneration, but accounts for approximately 90% of all cases of severe vision loss from the disease.
In wet age-related macular degeneration, abnormal blood vessels under the retina begin to grow toward the macula. Because these new blood vessels are abnormal, they tend to break, bleed, and leak fluid, damaging the macula and causing it to lift up and pull away from its base. This can result in a rapid and severe loss of central vision.
You can read more at What Treatments Are Available for Wet Macular Degeneration?
Barbara Beskind, 91-Year-Old Silicon Valley Tech Designer
Her advice for the millions of seniors in the United States who are experiencing age-related vision loss? "The more adaptable, organized, and self-disciplined you've been your whole life, the better you will be able to adjust to your needs as they come up. As we get older we have to expect change and embrace it."
Learn more about ways to adapt your home, following Barbara's design principles:
- Keep your household organized! Follow the principles of work simplification and energy conservation.
- Use tactile markings and "bump dots" to label a variety of household items.
- Learn to get around safely indoors and outdoors.
- Check out our Getting Started Kit for more ideas to help you live well with low vision.
- Sign up with VisionAware to receive free weekly email alerts for more helpful information and tips for everyday living with vision loss.
Clinical Trials for Macular Degeneration
In order to receive approval from the U.S. Food and Drug Administration (FDA), a new drug or treatment must be proven to be both safe and effective by undergoing a rigorous series of controlled unbiased studies. To prevent bias, neither the patient nor the examiners can know which patients received the actual treatment and which were the untreated (or "control") subjects.
These are called "double blind" or "double masked" studies and usually yield the most reliable results. The medication is coded and patients are placed at random into either the treatment or control group. When the study is concluded, the code is revealed and it is then possible to determine who received the actual drug and who received the inactive substance, or placebo.
As defined by the U.S. National Institutes of Health, most clinical trials are designated as Phase I, II, or III, based on the questions the study is seeking to answer:
- In Phase I clinical trials, researchers test a new drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe and effective dosage range, and identify possible side effects.
- In Phase II clinical trials, the study drug or treatment is given to a larger group of people (100-300) to determine if it is effective and to further evaluate its safety.
- In Phase III studies, the study drug or treatment is given to even larger groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
- In Phase IV studies, after the Food and Drug Administration has approved the drug, continuing studies will determine additional information, such as the drug's risks, side effects, benefits, and optimal use.
To learn more about clinical research on treatments for macular degeneration, you can visit the following resources:
- Clinical trial research on the VisionAware blog
- Macular degeneration research on the VisionAware blog
- The National Eye Institute website for information on clinical studies.
- The FDA has approved the Implantable Miniature Telescope (IMT) for end-stage AMD
- ClinicalTrials.gov provides a searchable list of all current clinical trials related to AMD.
- Macular Degeneration Partnership provides information on clinical trials for wet AMD, dry AMD, and a list of frequently asked questions about clinical trials.
Have an Eye Examination
If you have not had an eye exam by an ophthalmologist in three or more years, you may qualify for help from the AMD Eye Care Program, offered through the American Academy of Ophthalmology. The program provides free eye exams for individuals who have not been diagnosed with AMD, are age 65 and older, are U.S. citizens or legal residents, and do not belong to an HMO or the Veterans' Administration (VA). Call the toll-free helpline at 1-866-324-EYES (3937) for more information.
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- Author Ed Henkler Helps Readers Support Parents with Age-related Vision Loss
Ed Henkler, son of a mother with age-related macular degeneration, writes an e-book for helping families with useful tips and resources on dealing with vision loss. Read about his journey and his book.