What Is Macular Degeneration? 

Everything you need to know about this complex eye condition, which causes a loss of vision in the center of the eye.

Kristine Thomason May 09, 2017

If you’ve been lucky enough to have problem-free vision your entire life, it can be easy to take healthy eyes for granted. However, as we age, our vision starts to change—whether that means suddenly needing reading glasses or becoming more sensitive to light and glare. And as you get older, your eyes also become more and more susceptible to a number of conditions, such as cataracts, diabetic eye disease, low vision, and glaucoma.

Another common age-related condition is macular degeneration, a disease that affects more than 10 million Americans, and, according to the National Eye Institute is the leading cause of vision loss among people over 50. Still, despite its prevalence, there’s still a lot of confusion about macular degeneration. To suss out the facts, we spoke with Yasha Modi, MD, Assistant Clinical Professor in Ophthalmology at NYU Langone New York City, to answer common questions and learn crucial info about the eye condition.

What exactly is macular degeneration?

Put simply, when you hear about macular degeneration, people are generally talking about age-related macular degeneration (AMD). This refers to the breakdown of the central part of the retina, called the macula, which is responsible for the sharpest vision.

“Even though these patients never end up completely blind, they end up with central blind spots which severely limit their vision and daily function as well,” says Dr. Modi. “They have to rely on their peripheral vision, which requires a re-education on how to open bottles, navigate through doorways, and a number of everyday things that we otherwise take for granted.” And people with more advanced AMD often lose the ability to read, drive, see details, and recognize faces and colors.

It’s also important to note that macular degeneration includes a spectrum of diseases—generally classified as “early,” “intermediate,” and “late” AMD—that can progress over decades, says Dr. Modi. The earliest forms of AMD are often asymptomatic. However, over time, “patients may notice some distortion or central blurring of the vision, then as this progresses even further to scarring or atrophy of tissue, they end up with complete central blind spots.”

There are also two subgroups of AMD: dry and wet. With dry AMD, clumps of lipid and protein called "drusen" accumulate under the macula, and over time, the retina may progressively thin or atrophy. While wet AMD is when abnormal blood vessels start growing under the retina, which may leak blood or other fluids, scar the macula ,and cause vision loss. Dry is much more common than wet, and makes up about 80% of AMD cases, according to the American Academy of Ophthalmology. However, Dr. Modi points out that people who have wet AMD, usually have both wet and dry, which work together to affect their vision. So even if the wet form is remedied, they'll still have the dry variety. 

And although macular degeneration more commonly happens with age, Stargardt disease is a very rare type of macular degeneration that affects children and teenagers and is caused by a recessive gene, according to the American Macular Degeneration Foundation.

What are the symptoms?

Symptoms of dry macular degeneration tend to come on gradually, and can vary. They can include: visual distortions, reduced central vision in one or both eyes, the need for brighter light when reading, trouble adapting to low levels of light (like a dim restaurant), blurriness while trying to read, and difficulty recognizing faces.

These are all symptoms of late AMD. But if you notice your central vision is off, or you're having trouble recognizing colors and fine details, especially if you’re over 50, you should check with your doctor to find out if you're experiencing early signs.

Are there any risk factors?

Since most people are diagnosed with age-related macular degeneration, the biggest risk factor is being over 50, says Dr. Modi.

There’s also some evidence that genetics play a role. “We know that the majority of patients with macular degeneration derive from European ancestry,” he says. “And there are more very convincing signals that this is a genetically-inherited condition.” That said, there’s still no conclusive scientific evidence that AMD is linked to genetics.

While age and genetics are two things you have no control over, doctors have found other risk factors for AMD, especially smoking and diet.

"We know that patients who smoke have a higher risk of not only progressing to later stages of macular degeneration, but also having significant vision loss from macular degeneration," says Dr. Modi. That said, even if someone has smoked for a number of years, quitting immediately  can reduce the risk of AMD. 

Dr. Modi says studies have shown that diet can also play a role. He recommends eating a diet low in meats and animal fats, while getting plenty of veggies and dark leafy greens. 

Is it curable?

While there still isn’t a definitive cure for macular degeneration, Dr. Modi says there has been a lot of success treating patients with early stages of macular degeneration with “eye vitamins” or “AREDS” vitamins. In fact, the first trial of the Age Related Eye Disease Study (AREDS) found that taking a combination of vitamin C, vitamin E, beta-carotene, zinc, and copper reduced the risk of more advanced forms of AMD by 25%. And researchers tested a new formula that swapped lutein and zeaxanthin for beta-carotene (AREDS2) with similar results. 

For cases of wet macular degeneration, when there is a growth of blood vessels that can quickly compromise the quality of vision, doctors will apply medication directly into the eyes, Dr. Modi explains. This treatment helps preserve existing vision and even recover some lost vision if started early enough.

Is there any way to prevent it?

While many causes of AMD aren't preventable, Dr. Yasha points out it certainly doesn’t hurt to avoid smoking, focus on keeping your cholesterol at a healthy level, and maintaining an overall healthy lifestyle—especially if you have a family history of macular degeneration.

“It’s also important for patients to get appropriate clinical screenings, especially after the age of 50,” he says. In this case, that means an annual eye checkup, in which the pupils are dilated and the retina is thoroughly examined. This type of screening is not only important for detecting early stages of macular degeneration, he says, but also other eye conditions like glaucoma, that are often symptomless until they’ve become more serious. That way, you can catch the condition in the early stages, potentially keep it from progressing, and even reverse the effects through treatment.

Sources: health.com
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