Age-related macular degeneration. It’s a mouthful, right? All those words, put together, might not make much sense to you. You know it has to do with eyes and blindness, and that’s enough to make you pretty worried when your doc gives you an AMD diagnosis. It’s understandable, but maybe we can help lighten your stress load a little. This disease is serious, but highly treatable, and your odds of beating it are good if you address symptoms and start treatment right away. Here’s what you need to know.
We went to some of the nation's top retina specialists in ophthalmology to bring you the most up-to-date information possible.
Jason Hsu, M.D.Retina Specialist, Attending Surgeon
Raj Maturi, M.D.Retina Specialist, Clinical Associate Professor
Timothy G. Murray, M.D.President
What Is Age-Related Macular Degeneration?
Age-related macular degeneration, or AMD, is a leading cause of vision loss for people age 50 and older in the U.S. It’s estimated that as many as 14 million Americans have some form of this eye disease. And with our population aging every day, that number is only set to get higher. By 2050, the disease is expected to affect nearly 22 million people.
It’s not just an issue here at home, either: An estimated 196 million people worldwide have AMD.
Quick eye anatomy lesson. The front part of your eye is called the cornea. That’s the transparent area of the eye that covers the sclera (the white part), iris (the colored part that controls the pupil), and pupil (the round, black part that changes shape according to how much light your eye is exposed to).
Behind the cornea is the center part of your eye, which is filled with something called vitreous gel. Go beyond that to the back of the eye and there’s the retina, a thin layer of light-sensitive nerve tissue. It plays a big role in sight: Light enters the retina from the front of your eye, the retina changes it to electrical impulses and passes those along to the optic nerve, which in turn sends the impulses to your brain, and: Ta-da! You can see.
OK, let’s zero in on the retina for a minute. Inside here, there is a small, central area called the macula. The macula is responsible for “central” vision—the stuff you see when you look directly in front of you, like when you’re reading a book—as well as seeing fine detail and color.
Macular degeneration refers to a group of conditions that cause damage to your macula. AMD is one of those conditions, and as the “age-related” terms implies, the disease typically happens in people 50 and older. You can have AMD in both eyes or just one, and the status of the disease can progress in one eye and not the other.
Any disease that involves your ability to see is scary as heck, but the good news is that you don’t really (often) go blind with AMD. Even if you have a progressive form of AMD (know as wet AMD), treatment is highly effective and any vision loss is contained to the central part of your sight—you can still see “peripherally,” or out of the sides of your eyes.
How Do Doctors Diagnose AMD?
Determining the presence of this disease is usually a two-part process.
1. Eye Exam
After your pupil is dilated with eye drops, your doctor will use what’s called a slit lamp to see through your dilated pupil to the back of your eye. A slit lamp is basically a microscope with a bright light.
If you’ve ever been to an eye doc, you might have had this exam—you sit at a table, place your chin in a stand called a chin rest and your forehead against what’s called a forehead band to steady your head, and your doctor focuses that bright light into your eye.
Then your doc will look through a microscope to see your eye in detail, from the cornea to the retina, to help diagnose AMD.
2. Imaging Test
If AMD appears likely, after your eye exam your doctor will use an imaging device to take highly detailed images of your retina to determine the extent of your AMD and damage to your macula. These can include:
Optical coherence tomography (OCT): This imaging test uses light waves to take super-fast cross-section pictures of your retina. This is the main test that ophthalmologists will use to help diagnose and treat you if you have AMD, due to the precision it provides. If you are diagnosed with AMD, your doctor will often continue using OCT imaging throughout your treatment to track how the blood vessels in your eye are responding. OCT is a pretty simple test—you just sit in a chair, close to a machine that scans your eye quickly. It’s noninvasive and pain-free.
Fluorescein angiography (FA): The special camera in this test takes rapid, sequential pictures of the blood vessels and other structures of your retina after fluorescein dye is injected into an arm vein and then circulates in your eye, highlighting the blood vessels.
Indocyanine green angiography (ICGA): This diagnostic procedure uses ICG dye, also injected into an arm vein, to examine the blood flow in the choroid—the layer of blood vessels that lies underneath the retina. This test is different from FA because it can show leaks under a layer of blood—fluorescein can’t.
Based on the findings from your physical eye exam and the photos captured using these imaging devices, your doctor will determine if you have AMD, and if so, which type.
The American Academy of Ophthalmology, the leading eye society in the U.S., recommends that everyone over the age of 40 have a baseline visit to an ophthalmologist once, which often includes a physical exam with a slit lamp and imaging. While AMD specifically starts after 50, the sooner you start having regular eye exams, the better, because early treatment for wet AMD is known to yield better results. Also, a baseline eye exam could catch dry AMD progressing to wet before visual loss occurs.
What Are the AMD Types?
There are the two types of AMD, dry and wet:
Also called non-neovascular AMD, this type of AMD usually doesn’t have symptoms and is slow to progress. As a result, it’s slower to have visual loss than more progressive wet AMD. It’s also the most common type of AMD—about 80% to 90% of cases diagnosed are dry AMD.
Here’s what happens in dry AMD:
The retinal pigment epithelium (RPE) starts degenerating. This cell layer is just outside the retina and nourishes the all-important photoreceptor cells involved in sight, allowing molecules to travel in and out, and removing toxic inflammatory enzymes in the process. Chronic inflammation in the body can confuse RPE cells, and they stop performing their normal task of, essentially, taking the trash out.
In early-stage dry AMD, pale lesions called drusen form beneath the retina. Normally, your retinal and immune cells work together to rid your eye of such material through that RPE layer, but if the RPE is damaged, drusen can build up. The more drusen you have, and the bigger their size, the greater your future risk of vision loss.
In late-stage dry AMD, a scar can form caused by atrophy or wasting, called geographic atrophy (GA). This leads to central visual loss.
Dry AMD vison loss is less common than in wet AMD, accounting for 10% to 20% of legal blindness in AMD in total. But—and this is a big but—there’s no current medical treatment for dry AMD.
You can take special vitamins called the AREDS2 formula (which you can find at many stores, including pharmacies) that are helpful in stopping the progression of the disease, and there are new treatments for GA being explored in clinical studies, so hope for dry AMD is right around the corner.
But as of now, reducing your risk factors (we’ll go into those shortly) for progression in dry AMD is paramount.
Also called neovascular AMD, this type of AMD is a progression from dry AMD. Symptoms can include:
Loss of vision in the center of the eye (you can still see when you look out the sides of your eyes)
Blind spots in the center vision
Distortion of straight lines
Far less common than dry AMD, wet AMD happens in about 10% to 20% of AMD cases. But it’s serious: It causes 90% of legal blindness in AMD cases.
Here’s what happens in wet AMD:
The loss of those RPE cells allows abnormal blood vessels to grow into the macula from the choroid, part of the eye between the retina and sclera. This is known as choroidal neovascularization (CNV).
The body produces a compound called VEGF, to create new blood vessels. The bad part: These blood vessels are fragile, and so they leak fluid and blood. The leakage changes the retina’s structure, messing with your vision.
When advanced, CNV can even turn into what’s called a disciform scar, changing the normal anatomy of the outer retina and causing permanent central vision loss.
The very good news about wet AMD is this: There is effective treatment, and it offers a real chance at not only maintaining vision, but also potentially regaining lost vision caused by wet AMD and stopping progression from reaching the scarring stage.
The treatment is called anti-VEGF agents, and it’s a medication you’ll receive based on your individual needs, which could range from every 4 weeks to every 6 months and beyond.
These meds target the VEGF compound involved in creating the weakened blood vessels. Specifically, the drugs block the development of new capillaries so no leakage can occur.
These drugs don’t make the blood vessels go away, but they do stop them in their leaky tracks.
Vital to all of these treatments: Keeping your treatment appointments and making sure you keep getting the medication, to maintain vision and prevent visual loss.
Oh, and one other (really big) thing: Anti-VEGF drugs are given as a regular injection into your eye. Before you freak out, know this:
Many ophthalmologists use a numbing agent before administering the shot.
The medication is given through the side of your eye typically (so you don’t see the needle).
There is no pain. You might feel a little pressure during the shot, and possibly a feeling like a little sand in your eye for the next 24 hours.
It’s quick—it can take only seconds.
The anti-VEGF drugs approved by the U.S. Food and Drug Administration (FDA) are:
Doctors have also used Avastin (bevacizumab) as an “off-label” treatment, meaning it hasn’t been approved by the FDA for this use. The drug is approved for the treatment of cancers including colorectal, lung, breast, brain, and renal, and may slow the progression of wet AMD by restricting the growth of new blood vessels in the eye.
Another treatment for wet AMD, photodynamic therapy, can help control the blood vessel growth and bleeding. It’s often effective when combined with anti-VEFG treatment.
Who Treats AMD?
There best person to see for this disease is a retina specialist, an ophthalmologist who specializes in treating conditions/disease of the retina.
If you live in a rural area, or even a suburban one without a lot of nearby hospitals, you might worry that you won’t find one of these special docs. Don’t: It’s estimated that there’s a retina doc within 45 minutes of most people in the U.S.
The American Society of Retina Specialists features a Find a Retina Specialist, which can locate you one of the estimated 2,600 retina specialists practicing in the U.S. nearest you.
These docs have more training than opticians (who help you fit into eyeglasses) and optometrists (who establish the prescription for your vision correction). And they are more specialized in the retina than general ophthalmologists or ophthalmologists that specialize in other eye diseases—for instance, cataract surgeons or cornea specialists. An ophthalmologist who undergoes a 2-year fellowship for “subspecialty” training in the retina is considered a retina specialist.
This is the person with the most knowledge about what’s going on in your eye—i.e., this is the doc you want!
Even if you see a retina specialist for just one visit, doing so can help you establish the best care plan moving forward for this serious disease.
What Are Signs AMD Is Progressing?
Even with the best care team, you’ll be largely on your own after your diagnosis, figuring out how to live your life with AMD. If you have dry AMD, you’ll need to deal with the possibility that it could turn to more progressive wet AMD at any time.
Since early treatment for wet AMD is key, you’ll want to check your vision regularly for any signs that the disease is progressing. These are good ways to stay on top of your eye health:
Check your sight. Cover one eye. Look at the blinds in your house, a doorway, or an Excel spreadsheet. Are the lines distorted? Switch eyes and repeat. Use an Amsler grid (the common AMD visual test, showing a grid with a dot in the center) as the screensaver on your computer, or as the backdrop on your tablet. Distorted lines or inability to see the dot means it’s time to talk with your doctor.
Understand wet AMD symptoms. Central vision loss or blurry vision is the major manifestation for wet AMD—it’s what you need to be on the look-out for, in both eyes.
Give it a day, but only a day. If you notice a sudden visual distortion or blurriness, give it 24 hours. Still a problem? Call your eye doctor and ask for an urgent exam.
What Are the Causes and Risks for AMD?
You might be wondering, since it impacts so many people—what causes this disease? It’s an area of intense research but so far, the picture isn’t entirely clear (no pun intended).
There are strong theories: It appears oxidative stress and inflammation are key instigators in getting the ball rolling with AMD. Another potential cause? Your genes. If you inherit certain genes in a part of the immune system called the complement cascade, you have a higher risk for AMD.
While scientists continue to explore the roots of the disorder, here’s what we know about the established risk factors for AMD:
Age. Those 60 years and older are more likely to have AMD, and your risk goes up as you approach 80.
Race. AMD is a disease that occurs predominately in Caucasian people, affecting more than 14% of white Americans 80 years and older.
Genetics. Your risk of developing the disease is at least three-fold higher if you have a family member with it. One study even found that risk increases 27.8 times when a parent has the disease, and 12 times if your sister or brother has it.
Smoking/exposure to secondhand smoke. Smoking increases your risk of developing AMD. Quitting while you have dry AMD is a good idea too, and could only help, possibly even preventing additional progression.
Along with these known risk factors, there are others that experts think could play a role in AMD as well:
Sex. On average, women live longer than men and are also more likely to have this age-associated disease—nearly twice as likely by some reports.
Poor diet. Having a diet low in fish, lutein, zeaxanthin, and antioxidants, might lead to increased risk of AMD. Eating more healthy foods, including leafy green vegetables and fish, could have a protective nature against AMD and its progression.
Overall health. Losing weight, as well as maintaining a healthy blood pressure, good heart health, and lower cholesterol levels, might be vital lifestyle changes to reducing AMD risk factors as you age.
Of the two types of AMD, dry and wet, the only treatment currently is for wet (though a vitamin formula has been shown to help slow dry AMD progression to wet AMD). And that treatment for wet AMD? It's a medicine injected into the eye on a regular basis called anti-VEGF therapy.
How can I prevent AMD?
By reducing known risk factors, including smoking, eating a poor diet (eat one rich in green leafy veggies and fish instead), and weight if you’re overweight or obese. Having regular eye exams with an ophthalmologist can also help establish a baseline for your eye health.
What is worse—wet or dry AMD?
While wet AMD has an effective treatment, anti-VEGF therapy, it’s also the more progressive kind of AMD with symptoms, including blurry vision and distortion. Dry AMD often doesn’t progress and has limited to no symptoms, though it doesn’t have a medical treatment at the moment.
What does AMD stand for?
Age-related (because you’re at increased risk of having it if you’re over the age of 60) macular (because it impacts the part of the eye called the macula, located in the retina, which is in the back of the eye) degeneration (which basically means deterioration).
AMD and Risk Factors:Investigative Ophthalmology & Visual Science. (2009). “Predication Model of Advanced Age-Related Macular Degeneration Based on Genetic, Demographic, and Environmental Variables.” ncbi.nlm.nih.gov/pubmed/19117936