Age-Related Macular Degeneration – Vista Center for the Blind and Visually Impaired

What Is Age-Related Macular Degeneration?

Age-related macular degeneration (AMD) is a problem with your retina, the light-sensing nerve tissue at the back of the eye. It happens when the centermost part of the retina, called the macula, is damaged. With AMD you lose your central vision. You cannot see fine details, whether you are looking at something close or far. But your peripheral (side) vision will still be normal. For instance, imagine you are looking at a clock with hands. With AMD, you might see the clock’s numbers but not the hands. AMD is very common. It is a leading cause of vision loss in people 50 years or older.

There are two types of AMD, dry AMD and wet AMD. About 80% (8 out of 10) of people who have AMD have the dry form. Dry AMD is when parts of the macula get thinner with age and tiny yellow deposits made up of lipids (fats) and protein, called drusen, grow. You slowly lose central vision. The last stage of dry AMD is called geographic atrophy. In this stage, the drusen damage is so extensive that it causes blind spots in the patient’s central vision. Up to 20% of people with AMD develop geographic atrophy. While geographic atrophy is more commonly associated with the dry subtype of AMD, it is possible for people to have both wet and dry AMD at the same time, and to develop geographic atrophy independently of having wet AMD.

Wet AMD is less common but much more serious. Wet AMD is when new, abnormal blood vessels grow under the retina. These vessels may leak blood or other fluids, causing scarring of the macula. You lose vision faster with wet AMD than with dry AMD.

Many people don’t realize they have AMD until their vision is very blurry. This is why it is important to have regular visits to an ophthalmologist. He or she can look for early signs of AMD before you have any vision problems.

Who Is at Risk for AMD?

You are more likely to develop AMD if you eat a diet high in saturated fat (found in foods like meat, butter, and cheese), are overweight, smoke cigarettes, are over 50 years old, have hypertension (high blood pressure), or have a family history of AMD. Having heart disease is another risk factor for AMD, as is having high cholesterol levels. Caucasians (white people) also have an elevated risk of getting AMD.

How Is AMD Diagnosed?

During an eye exam, your ophthalmologist may ask you to look at an Amsler grid. This grid helps you notice any blurry, distorted, or blank spots in your field of vision.
Your ophthalmologist will put dilating eye drops in your eye to widen your pupil. This allows him or her to look through a special lens at the inside of your eye to see if there are changes in the retina and macula.
Your doctor may do fluorescein angiography to see what is happening with your retina. Yellow dye (called fluorescein) is injected into a vein, usually in your arm. The dye travels through your blood vessels. A special camera takes photos of the retina as the dye travels throughout its blood vessels. This shows if abnormal new blood vessels are growing under the retina.
Optical coherence tomography (OCT) is another way to look closely at the retina. A machine scans the retina and provides very detailed images of the retina and macula.
Optical coherence tomography angiography (OCTA) is another way to look closely at the blood vessels in and under the retina. This is like fluorescein angiography but does not use a dye.

How Is AMD Treated?

Dry AMD Treatment

Right now, there is no way to treat dry AMD that has not progressed to geographic atrophy. However, people who have a lot of drusen might benefit from taking a certain combination of nutritional supplements. A large study (AREDS and the later AREDS 2 study) found those people may slow the progression of intermediate to late-stage AMD by taking these vitamins and minerals daily: Vitamin C (500 mg), Vitamin E (400 IU), Lutein (10 mg), Zeaxanthin (2 mg), Zinc (80 mg), and Copper (2 mg). Your ophthalmologist can tell you if vitamins and minerals are recommended for your AMD, as not all forms will benefit from the AREDS supplements. Beta carotene should not be used by smokers as it raises the risk of lung cancer.

Dark leafy greens, yellow fruits and vegetables, fish, and a balanced, nutrient-rich diet have also been shown to be beneficial for people with AMD.

Geographic atrophy can be treated with eye injections of a newly approved drug called pegcetacoplan (Syfovre).

Wet AMD Treatment:

To help treat wet AMD, there are medications called anti-VEGF drugs. VEGF, which stands for vascular endothelial growth factor, is a protein that is important in the growth and development of new blood vessels. Anti-VEGF treatment helps reduce the number of abnormal blood vessels in your retina. It also slows any leaking from blood vessels. This medicine is delivered to your eye through a very slender needle.

Laser surgery may also be used to treat some types of wet AMD. Your eye surgeon shines a laser light beam on the abnormal blood vessels. This reduces the number of vessels and slows their leaking. Talk with your ophthalmologist about ways to treat your AMD.

What Are Some Emerging Treatments for AMD?

Emerging Treatments for Wet AMD

The primary drawback to anti-VEGF injections is that they must be given into the back of the eye every four to six weeks. Today, there’s hope for new types of anti-VEGF treatments that will not need to be administered as often as the current, four- to six-week regimen. Some experts say that a few treatments being developed today may possibly even cure the disease.

One promising new treatment for wet AMD involves retinal gene therapy as an alternative to monthly eye injections. The goal of gene therapy is to employ the body to make its own anti-VEGF by inserting a harmless virus (called an adeno-associated virus/AAV) carrying the anti-VEGF gene into a person’s DNA. RGX-314 gene therapy only requires one injection, but it must be performed via a surgical procedure. ADVM-022 gene therapy can be administered in an outpatient setting (such as the doctor’s office). Both treatments are currently moving through clinical research trials.

The Port Delivery System (PDS) is a very small (smaller than a grain of rice) apparatus that can store anti-VEGF medication. The PDS is implanted into the eye during a surgical procedure. It provides a continuous release of anti-VEGF medication into the eye. The PDS enables people with wet AMD to go up to two years without needing a treatment. While it was initially approved for wet AMD in October of 2021, it was subsequently recalled in October 2022 due to problems with the seal on the device that keeps medicine from leaking out once it’s been injected. The manufacturers hope to have it back on the market later this year.

Anti-VEGF eye drops for wet AMD is another new treatment modality for AMD that has been tested on animals. Once the medicated eye drops are considered safe enough for human use, clinical trials will begin. It may take until the year 2030 for anti-VEGF eye drops for wet AMD to be available for consumer use.

An anti-VEGF pill, to be taken orally (by mouth) may be available to the public by 2025. The pill form of the medication will enable people with wet AMD to eliminate or reduce the frequency of anti-VEGF injections. Now in clinical trials, developers of oral medication for wet AMD are trying to work out the bugs. The medication has many side effects right now, such as nausea, leg cramps and liver changes. Once the medication can be considered safe, and dangerous side effects can be eliminated, it can be considered for consumer consumption.

Several new longer-lasting anti-VEGF medications—aimed at reducing the frequency of injections—are being developed by the drug industry. These include drugs such as Abicipar, and Sunitinab, which are estimated to become available between 2023 and 2025. Another new drug, Beovu has already been approved for use in the U.S. Beovu injections can last as long as three months and the innovative medication is said to be more effective at drying fluid that has accumulated in the retina due to wet AMD.

New combination medications for AMD include a combination of drugs that are already on the market, for treatment of AMD. The goal is a multi-faceted treatment approach aimed at increasing the benefit of the drugs and making the injections last longer. One such combination is an eye drop to treat glaucoma, called Cosopt (dorzolamide-timolol), being tested in combination with anti-VEGF injections. Studies indicate that these two drugs, when given together, may help to lower retinal fluid better than just anti-VEGF injections can accomplish alone.

Radiation therapy, similar to the type of treatment commonly used to treat cancer, is thought to help slow the growth of abnormal blood vessels caused by wet AMD. Radiation therapy is said to work the same way it does in cancer treatment. This is accomplished by destroying fast-growing cells. But long-term safety must still be evaluated before radiation therapy can be considered as a mainstream option for AMD treatment. There are two types of radiation therapy available in the UK and Switzerland and they will soon be tested in the United States.

Emerging Treatments for Dry AMD

Stem cell therapy is gaining momentum for all types of treatment today, including many forms of cancer, as well as for dry AMD. The goal of stem cell therapy for AMD is that the new stem cells will be able to replace retinal cells that have been damaged or destroyed by symptoms of AMD. Stem cells are often introduced into the body’s blood circulation, via IV infusion. But researchers are working on how to transplant the stem cells directly into the eyes. One strategy involves placing the stem cells into a fluid suspension that can be injected under the retina. Although stem cell therapy for AMD has only been studied in small clinical trials, the experts say this treatment regime shows great promise. The drawback is that stem cell therapy may not be proven safe for consumers until 2030 to 2035.

Photobiomodulation (PBM) is a non-invasive therapy that has shown promise in sustaining vision and slowing the progression of dry AMD in clinical trials. It is suitable for patients with early to intermediate dry AMD.

Zimura (avacincaptad pegol) is a drug that can be injected intravitreally (directly into the back of the eye) to help slow the progress of dry AMD, protecting the retinal cells from being destroyed. This treatment is in clinical trials and is expected to be available around 2023 to 2025. Oracea, an oral antibiotic with anti-inflammatory properties, may be available for people in the late stage of dry AMD. Oracea is currently in clinical trials. Metformin, a drug commonly given to people who have diabetes, was found to lower the risk of development of AMD. This may be due to metformin’s anti-inflammatory properties. Metformin is in clinical trials.

Sources

Boyd, Kierstan. “What is macular degeneration?” American Academy of Ophthalmology, 6 Apr. 2023, www.aao.org/eye-health/diseases/amd-macular-degeneration

Wendt, Taylor. “What Is Geographic Atrophy?” WebMD, 31 Aug. 2022, www.webmd.com/eye-health/what-is-geographic-atrophy

Bankhead, Charles. “FDA Approves First Treatment for Geographic Atrophy Secondary to AMD.” MedPage Today, 18 Feb. 2023, www.medpagetoday.com/ophthalmology/generalophthalmology/103184

Christiansen, Sherry. “Macular Degeneration Breakthroughs.” Verywell Health, Feb. 2023, www.verywellhealth.com/macular-degeneration-emerging-treatments-5071096

“Roche Recalls New Eye Therapy Susvimo on Leakage Fears, Aims for Market Return ‘within a Year or So.’” Fierce Pharma, 18 Oct. 2022, www.fiercepharma.com/manufacturing/roche-recalls-susvimo-implant-lucentis-leakage-fears-return-market-expected-within

“Vision Improvements Sustained With Photobiomodulation at 24 Months in Dry AMD Trial.” Healio, 16 Mar. 2023, www.healio.com/news/ophthalmology/20230316/vision-improvements-sustained-with-photobiomodulation-at-24-months-in-dry-amd-trial.

For more information on AMD, you can subscribe to the free monthly e-mail AMD-Retina research update. Contact thl@vistacenter.org.

Compiled/edited by M. Kaplan, PhD, 5/2023.

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