Age-Related Macular Degeneration (AMD)

The retina is a thin layer of photosensitive tissue that lines the back of the eye. Its primary function is to receive light and send the light signals to the brain via the optic nerve. The central portion of the retina is the macula. This oval-shaped area is responsible for our central vision and makes it possible for us to read, see things in fine detail, recognize faces, see color, drive, and more.

As we age, our macula can deteriorate. This condition is known as age-related macular degeneration (AMD). It is the leading cause of age-related blindness in adults over the age of 50. According to the American Academy of Ophthalmology, this condition affects up to 15 million people in North America.

Learn more about Macular Degeneration from Dr. Fastenberg and Dr. Rosenblatt on the VRC Podcast, Retina in Focus.

Dry Macular Degeneration

The most common form of macular degeneration is dry AMD. It can affect one or both eyes. It is typically painless, but can cause vision changes such as distortions, increased blurriness, decreased sense of color, or the need for brighter light.

Wet AMD

For approximately 10% of AMD patients, dry AMD can lead to a serious form of macular degeneration known as wet AMD. Wet AMD occurs when abnormal blood vessels form in the retina area and leak blood or fluid into the macula, which inhibits the retina’s ability to function properly. In some cases, wet AMD can lead to permanent vision loss.

Macular Degeneration Symptoms

In its earliest stages of AMD, there may be no apparent symptoms. However, as the condition progresses, you may experience several changes to your vision, including:

• Blurry vision
• Difficulty reading
• Straight lines appear distorted
• Changes in color perception
• Darkened central vision

How Macular Degeneration is Diagnosed

When being examined for macular degeneration, your doctor will look for the presence of drusen, which are yellow or white deposits of fatty proteins that accumulate under the retina. Small amounts of drusen are a natural part of aging, but the presence of medium-to-large drusen can indicate macular degeneration.

Examining the amount and size of drusen helps retina specialists determine what stage AMD has progressed to. In early macular degeneration, there are typically only small drusen or a few medium-sized deposits, whereas intermediate macular degeneration will be accompanied by either several medium drusen or one large drusen. The presence of large drusen in both eyes increases the likelihood of developing advanced macular degeneration.

There are several diagnostic tests that retina specialists use to determine whether a patient has developed AMD and/or how far the condition has progressed. These tests include:

• Eye dilation: This is an eye exam in which special eye drops are used to keep the pupil open. This exam allows eye physicians to get a better look at the retina, macula, and optic nerve. Eye dilation is a standard part of an annual eye exam and will alert a physician to the presence of drusen.
• Optical coherence tomography (OCT): In this non-invasive imaging diagnostic method, infrared light waves are used to capture cross-sectional images of the retina. OCT helps retina specialists gather information on drusen as well as blood vessels and overall retina structure.
• Fluorescein angiography: This is a test in which colored dye is injected into the bloodstream so that it can migrate to blood vessels in the eye. As the dye travels to the ocular blood vessels, a special camera is used to capture images that will reveal the presence of retinal abnormalities.
• Indocyanine green angiography: Similar to fluorescein angiography, this test also uses an intravenous injection of colored dye and a special camera to capture images of blood flow in the eye. The main difference is the dye used. In indocyanine green angiography, the dye illuminates when exposed to infrared light, making it easier to see the deeper blood vessels in the retina.

Preventing Dry Age-Related Macular Degeneration

Currently, there is no cure for dry AMD. As such, the best way to manage dry AMD is through prevention. Patients should be aware of the symptoms of AMD, as well as the main risk factors associated with it, including age, obesity, high blood pressure, and high cholesterol. Good preventative measures include:

• Getting your eyes examined regularly
• Eating healthy foods
• Not smoking
• Wearing sunglasses
• Maintaining a healthy weight
• Maintaining healthy blood pressure and cholesterol levels

Medications for Wet AMD

There are a few treatment options available for managing the progression of wet AMD and protecting your existing vision, including:

• Focal laser surgery, also known as photocoagulation: In this procedure, a high-energy laser is used to close abnormal blood vessels to stop them from bleeding and causing further damage to the macula.
• Photodynamic therapy: This is a procedure in which a light-activated drug is injected into the bloodstream so that it can travel to the ocular blood vessels. Once the drug has reached these blood vessels, a laser is used to shine a light on the eye and activate the drug, which then seals the abnormal blood vessels.
• Anti-vascular endothelial growth factor (anti-VEGF) medications: This refers to a family of drugs that inhibit the growth of blood vessels in the eye. Common examples of these medications include Avastin, Lucentis, and Eylea. Anti-VEGFs are injected directly into the eye. The eye is numbed before the injection is administered.

Age-Related Macular Degeneration: FAQ

For more information, please visit the American Society of Retina Specialists website.