Understanding Wet Age-Related Macular Degeneration

Receiving a diagnosis of wet age-related macular degeneration (AMD) may explain what’s causing the blurring, distortion, or missing spots in your vision, but also prompt other questions. Wet AMD can lead to severe vision loss, but what does this mean, how does it happen, and most important, what can you do about it?

What Is Wet AMD?

AMD affects a thin layer of tissue inside the eye, behind the retina (called the choroid). When the condition develops, the center of the retina — the macula, which is the part of the eye that allows you to see details, such as recognizing faces and reading — is affected, leading to vision loss.

According to the National Eye Institute (NEI), AMD is the leading cause of vision loss in the United States. It affects more than 11 million people, and that number is expected to rise to epidemic proportions in the next 10 years.

There are two types of AMD: wet and dry. “Wet AMD is a progression of dry AMD,” says Alex Yuan, MD, PhD , an ophthalmologist at Cleveland Clinic in Ohio. “The wet refers to the leakage of fluid under and into the retina.”

Without treatment, patients with wet AMD can lose central vision very quickly, he adds.

Macular degeneration begins with a buildup of waste products (called drusen) under the macula, which can cause blurring and distortion of your vision. This is known as dry AMD.

“Early and intermediate dry AMD might not affect vision much, but late or advanced dry AMD can result in atrophy, which can affect central vision. But vision loss in dry AMD is much slower,” Dr. Yuan explains.

In some people with dry AMD, abnormal blood-vessel growth occurs underneath and into the retina, which may cause swelling and bleeding and lead to rapid changes in vision. When this happens, the condition becomes wet AMD.

Most people with AMD have the dry type, according to the American Foundation for the Blind. But for approximately 10 to 15 percent of people with dry AMD, the condition progresses to wet AMD, according to the American Macular Degeneration Foundation (AMDF).

Is Wet AMD Genetic?

AMD has both genetic and environmental causes. According to the BrightFocus Foundation, people who have a parent with AMD have about twice the risk of developing it themselves compared with those who don’t have a family history of the condition.

In addition, some research has found genes that are associated with wet AMD and with the progression of dry AMD to wet AMD.

At present, genetic testing is not recommended to assess AMD or wet AMD risk. However, people with a family history of AMD are advised to reduce their environmental risks by stopping smoking if they smoke, wearing sunglasses outdoors, and following a diet high in fruits, vegetables, and food sources of omega-3 fatty acids such as fatty fish, nuts, and seeds.

They should also have their vision checked regularly by an ophthalmologist.

Signs and Symptoms

The signs and symptoms of wet AMD often happen slowly, over time. You may see one dark spot or several in the center of your field of vision, the AMDF explains. When looking at lines or a grid, you may notice that lines appear wavy or blurry, according to the American Academy of Ophthalmology.

When reading, at least initially, you may notice that the letters appear somewhat distorted or broken, a phenomenon known as metamorphopsia.

“It can be like looking at a fun-house mirror,” Yuan says.

Wet AMD can affect one or both eyes, he adds, while dry AMD usually impacts both eyes. Some people don’t notice any vision changes, which makes regular exams by an ophthalmologist essential, because your doctor can look for early warning signs.

Causes

No one knows what triggers dry AMD to become wet AMD. In some people with dry AMD, cells inside the macula produce growth factors — the most important being vascular endothelial growth factor (VEGF) — that cause the formation of abnormal blood vessels.. This protein can contribute to the progression from dry to wet AMD.

Risk Factors

Age is the biggest risk factor for wet AMD. The condition typically occurs after age 60, but it can develop in younger people, too, according to the NEI.

Other risk factors for wet AMD include:

• Being white
• Having a family history of AMD
• Smoking
• Having heart disease
• Having high cholesterol
• Being overweight
• Eating foods rich in saturated fats

Managing the Condition

Although there’s no cure for wet AMD, early diagnosis is important, because therapies can slow its progression and help preserve vision.

“Wet AMD has several excellent treatments,” says Yuan. “Early treatment, before the vision is really poor, results in better vision.”

They are several excellent treatment options to help slow the progression of the condition, according to Yuan, including a growing class of anti-VEGF agents. There’s also a novel surgical option involving a long-acting delivery device, he adds.