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 may progress to the wet type in 10-20% of individuals. Age-related macular degeneration is usually 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. The dry AMD tends to progress more slowly than the wet type, and there is not 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.

Drusen are the hallmark of dry AMD. These small yellow deposits beneath the retina are a buildup of waste materials. They are made up of cholesterol, protein, and fats. Typically, when drusen first form, they don’t cause any vision loss. However, they are a risk factor for progressing to vision loss. When a person has more advanced dry macular degeneration, there are many more of these small yellowish deposits that are larger.

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. Wet AMD tends to progress rapidly and causes severe loss of central vision. In this form, the degeneration of the macula causes the retina to create a protein called VEGF. This is made by the retina to protect itself and to create new blood vessels. However, this attempt is futile as those new blood vessels are abnormal. In wet AMD, these abnormal blood vessels tend to break, bleed and leak fluid which causes damage to the macula. After some time, a scar overlies the entire macula causing severe loss of central vision.

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 EyeCare America – American Academy of Ophthalmology (aao.org) program offered through the American Academy of Ophthalmology.  According to EyeCare America, “The Seniors Program connects eligible seniors 65 and older with local volunteer ophthalmologists who provide a medical eye exam often at no out-of-pocket cost, and up to one year of followup care for any condition diagnosed during the initial exam, for the physician services.”

Call the toll-free helpline at 1-866-324-EYES (3937) for more information.

By Lylas G. Mogk, M.D., Edited by Sefy Paulose, M.D., March, 2022

What Treatments are Available for Dry Macular Degeneration?

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. There is no mainstay treatment for dry AMD. However, depending on the stage of dry AMD, taking a particular supplement can help slow the progression of dry AMD.

AREDS2

This supplement is called AREDS2. Studies have found that the following formulation can help decrease the progression of dry AMD: 500 milligrams (mg) of vitamin C, 400 international units of vitamin E, 80 mg zinc as zinc oxide, 2 mg copper as cupric oxide (to avoid anemia with high zinc intake), 10 mg lutein and 2 mg zeaxanthin. However, ask your doctor before taking this supplement, as the AREDS2 clinical trial has shown no benefit for mild stages of AMD.

Modifiable Risk Factors

Studies suggest that modifiable risk factors may help slow the progression of AMD or prevent worsening. The most studied and proven modifiable risk factor is smoking. Studies have shown that smokers have an increased risk of dry AMD than nonsmokers. Also, ex-smokers have a decreased risk of dry AMD than current smokers. By stopping smoking, you will help prevent the progression of dry AMD

Certain vegetables contain lutein, which protects the macula from further damage. Thus studies have shown that increasing the quantity of antioxidant-rich foods, such as fresh fruits and dark green leafy vegetables (kale, collard greens, and spinach, for example). Other studies have also suggested eating fatty fish to reduce the severity of dry AMD as these fish are high in omega-3 fatty acids which help decrease inflammation.

Obesity and uncontrolled hypertension are two known risk factors that worsen the disease progression of AMD. Because of this, incorporate regular exercise and following with your primary care provider about combating obesity and hypertension.

What Treatments Are Available for Wet Macular Degeneration?

In wet (neovascular/exudative) age-related macular degeneration (AMD), abnormal blood vessels develop under the macula and break, bleed, and leak fluid. This damages the macula and, if left untreated, can result in rapid and severe loss of central vision.

Targeting Vascular Endothelial Growth Factor (VEGF)

The most effective treatments to date for wet AMD are medications that target the protein that causes the abnormal blood vessels to form, Vascular endothelial growth factor (VEGF), a protein produced by a damaged retina that causes the production of abnormal blood vessels. However, these blood vessels damage your eye more by causing worsening swelling and bleeding and can cause scars that can pull on your retina and cause a retinal detachment.

Injections

In these cases, your doctor may treat you with an injection of anti-VEGF medicine. Anti-VEGF medicine blocks VEGF which prevents the growth of new blood vessels in the eye. Although the main role of anti-VEGF injections is to prevent your vision from getting worse, this medication can sometimes improve your vision. Your ophthalmologist may give you three types of anti-VEGF medications – Avastin, Lucentis, and Eylea.

Laser

In some very aggressive wet AMD scenarios, your doctor may also recommend laser treatment called photodynamic therapy (cold laser). The purpose of this laser is to slow down progression. Although this laser does not prevent significant vision loss, it may be used in some rare instances of exudative AMD.

Surgical

If there is still a concern for worsening wet AMD, your doctor may suggest surgical treatment. However, these surgical procedures were developed before the invention of anti-VEGF treatments. For the most part, these surgical treatments are rarely used.

By Lylas G. Mogk, M.D., Updated by Sefy Paulose, M.D., March. 2022

Clinical Trials for Macular Degeneration

To receive approval from the U.S. Food and Drug Administration (FDA), a new drug or treatment must be proven 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 evaluate its safety further.
• 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.

Read More:

• The National Eye Institute website for information on clinical studies.
• ClinicalTrials.gov provides a searchable list of all current clinical trials related to AMD.
• The Bright Focus Foundation has a fact sheet on clinical trial information for macular degeneration.
• Macular Degeneration: Symptoms, Diagnosis & Treatment (clevelandclinic.org)