How Age-Related Macular Degeneration Can Harm Your Vision
Imagine life with worsening vision — the increasing difficulty of everyday tasks and frustration of adjusting to lower vision. Unfortunately, this is a reality for many individuals diagnosed with age-related macular degeneration, or AMD.
More than 10 million Americans are affected by AMD, and it is a leading cause of vision loss among individuals aged 50 or older.
Doctors at Dean McGee Eye Institute (DMEI) frequently treat AMD. Our physicians work with patients to help them understand the disease’s risks, how it affects vision, and how to proceed after an AMD diagnosis.
What is Age-Related Macular Degeneration?
AMD is a condition that causes damage to the eye’s macula. The macula is at the center of the retina and is responsible for providing clear, central vision. It’s made up of light-sensitive tissue and allows the eye to focus on fine print and other small visual points that require refined focus. It’s the reason you can see to thread a needle. AMD causes the macula tissue to break down.
How Does Age-Related Macular Degeneration Affect Vision?
With early AMD symptoms, a patient may experience difficulties seeing in harsh light and dark situations. As AMD develops, it causes central vision to become blurry and dark.
“Vision may fluctuate in different lighting conditions,” says Dr. Kingsley, a clinical professor of ophthalmology at DMEI. “For example, if it’s too dim or too light you won’t be able to see very well as it may also take longer to adjust to extreme dark and light.”
Eventually, blurriness and gaps in vision can develop. While the condition doesn’t cause total blindness, it can be debilitating in serious cases.
How is Age-Related Macular Degeneration Diagnosed?
The condition can be identified through several types of eye exams, including a comprehensive dilated eye exam or an Amsler grid test.
“The Amsler grid test helps identify age-related macular degeneration,” Dr. Kingsley says. “If the distortion becomes more prevalent each time the test is taken, that could be a sign that the AMD has become more significant.
Patients can even perform the test at home by printing the grid out on a piece of paper and looking at it with each eye separately. It’s important to make sure the lines are all straight and nothing’s missing. You should take the test once a day holding the grid at reading distance.
Other tests your doctor may perform include fluorescein angiography, indocyanine green angiography, or an optical coherence tomography. During the diagnosis process, doctors will also look for drusen, which are small, yellow deposits under the retina. These deposits can indicate AMD.
The Three Stages of Age-Related Macular Degeneration
AMD can advance slowly, according to the National Eye Institute, and there are three stages of AMD: early, intermediate, and late. Each is characterized by a different level of vision loss.
Patients with early AMD have no vision loss and may not show symptoms. Usually, AMD is diagnosed by the appearance of medium-sized drusen.
Intermediate AMD is characterized by larger drusen or discoloration of the retina. Vision loss may occur at this stage, but it’s also common not to experience any symptoms. Both early and intermediate AMD can only be detected with an exam.
Patients with late AMD experience vision loss caused by the damage to the macula. Large drusen are present. Late AMD can take two forms: dry AMD and wet AMD.
Dry AMD, also called geographic atrophy, causes the breakdown of light-sensitive cells that bring visual information to the brain. Supporting tissue under the macula also breaks down. Both issues cause vision loss.
Wet AMD, also called neovascular AMD, is caused by an abnormal growth of blood vessels underneath the retina. This growth can cause macula-damaging bleeding and leakage. Unlike dry AMD, wet AMD develops rapidly.
“Sometimes wet AMD can happen overnight — where all of a sudden you have normal blood vessels and that can change when they start to bleed or leak fluid, then you wake up and can’t see as well,” Dr. Kingsley says. “Dry AMD usually progresses slowly over the years. However, it always varies among patients.”
What Are the Risk Factors of Age-Related Macular Degeneration?
Several factors may lead you to be at risk of developing AMD.
AMD is most likely to develop in people older than 60.
If AMD runs in your family, you’re more likely to develop AMD than individuals without a family history of the condition.
Caucasians have a higher risk of AMD compared to Hispanic, Latino, and African-American populations.
There is a correlation between smoking and an increased risk of AMD. Smokers have nearly double the chance of developing AMD compared to non-smokers.
Research has also shown that certain lifestyle choices can affect AMD. Regular exercise, a healthy diet rich in leafy green vegetables, avoiding smoking, and healthy blood pressure can help lower the risk of AMD.
While there isn’t a treatment for early AMD, it can be monitored for progression and there are measures you can take to help slow it down. Later stages are typically treated with several types of injections to prevent further damage.
“During early and intermediate AMD stages, we will typically prescribe antioxidant vitamins called Areds-2,” Dr. Kingsley says. “These key antioxidants help slow down the progression of AMD by 25%.”
For later AMD stages, drug injections are the main source of treatment. Injections are able to improve vision by approximately 30-40%. In some patients, 50% of vision stays the same after injections and 10% may get worse with injections. However, 80-90% percent of a patient’s vision will, in fact, get worse if you don’t do anything at all.
“It’s important to recognize that with AMD, you have to maintain treatment and it is a long term process,” Dr. Kingsley says. “If you stop the injections, the bleeding can come right back.”
New and Developing Treatments
DMEI participates in clinical trials to help develop new treatment options for our patients. Our researchers and clinicians are at the forefront of the latest findings for AMD treatments and have seen promising results in recent years.
“There’s a new drug that is similar to the drug injections we use now that is supposed to last longer,” Dr. Kingsley says. “This would mean that we wouldn’t have to do injections as frequently, lasting 12 weeks instead of the eight weeks we are seeing now.”
Our researchers are also participating in a study to test administering injections under the skin to stabilize the deterioration of the nerve cells and help slow the progression of AMD.
Lastly, a clinical trial that is in late stages of development is studying the effectiveness of implanting a refillable reservoir behind the pupil. This is so doctors can place the drug in the reservoir behind the pupil where it will slowly release the drug over a long period of time and eliminate the need for frequent injections.
Related Age-Related Macular Degeneration Information
DMEI is committed to providing the best treatment for all eye patients, including those suffering from AMD. DMEI is home to several retina and macular specialists who are ranked among the best doctors in the field.
Additionally, DMEI hosts an annual Macular Degeneration/Low Vision/Glaucoma Seminar that brings together experts to share their knowledge with patients and practitioners. The 2020 seminar will be held on Friday, November 20 at the Samis Education Center at the OU Children’s Hospital.
By staying at the forefront of research and education, we ensure we offer the best in care. If you think you or a loved one might be at risk for AMD, now is the time to request a comprehensive eye exam.