Geographic atrophy is the advanced stage of age-related macular degeneration. Certain factors can increase the risk of developing GA, but there are things you can do to reduce the influence of non-genetic risk factors.
Age-related macular degeneration (AMD) is a progressive eye disease, which means that it gets worse over time. AMD damages the macula — the part of your retina that gives you clear straight-ahead vision.
The disease has three stages: early (dry), intermediate (dry), and late (dry or wet). Geographic atrophy (GA) is the late, or advanced stage of AMD.
Atrophy is when cells in your retina waste away, which can cause blind spots in your vision. Geographic refers to the sharply defined regions of damaged retina. It can lead to permanent vision loss.
Not everyone with AMD develops GA. Here are some of the factors that increase your risk and condition progression.
Age is one of the biggest risk factors for both AMD and GA. Most people with GA are over 60. The retina changes with age in ways that make it more likely to become damaged.
AMD can run in families. The genes you inherit from your parents not only affect your risk of getting AMD but also of it turning into GA.
Researchers have found several gene variants linked to AMD progression. These include genes involved with inflammation, cell survival, and fat transport in the body.
Smoking not only contributes to heart disease, cancer, and lung disease. It’s also harmful to your eyes.
Tobacco smoke contains a mix of toxic chemicals that damage the retina as they travel through its blood vessels. Smoking also contributes to oxidative stress — an imbalance between harmful molecules called free radicals and the antioxidants that help your body fight off free radicals.
The more you smoke, the greater your AMD risk. The good news is that
Rates of AMD differ by ethnic background. White people of European descent have higher rates of AMD than people of other ethnicities. One reason may be that they have less melanin, a pigment that filters sunlight and protects the retina from damage. Genes are another possible reason for the difference in AMD rates.
Asian people often have a different type of AMD. They have less drusen, which are yellow deposits that damage the macula in AMD. Researchers found that in most Asian people, the disease progresses more slowly than it does in people of other ethnicities.
Having a high body mass index (BMI) might increase the risk of AMD and its progression. A 2016 review of seven studies found a 32% increased risk of late AMD in people who were obese.
Inflammation could be behind the link. Fat cells release more inflammatory chemicals like cytokines that damage the eye.
Fat tissue also stores carotenoids, plant pigments that promote eye health. This leaves fewer carotenoids available for the retina.
Having one of these diseases might increase your risk for AMD and GA:
- Cataracts: Some studies have found that cataracts and the surgery to remove them increase the risk for AMD and make it progress faster. Cataracts and AMD also share common risks like age, smoking, and obesity.
- Chronic kidney disease: Some studies have found a link between AMD and chronic kidney disease, while others haven’t. As with cataracts, the two conditions may share common risks like age and inflammation.
- Coronary heart disease: Heart disease and AMD are both linked to high blood pressure, smoking, and obesity. The same cholesterol deposits that collect in the arteries in heart disease can damage the retina.
- High blood pressure: Consistently high blood pressure damages blood vessels, including ones that nourish the retina. Yet there’s no evidence that treating high blood pressure reduces the risk of AMD progression.
- Hyperthyroidism: An overactive thyroid gland produces too much hormone. Excess thyroid hormone speeds up the body’s metabolism, which could increase damaging oxidative stress.
- Obesity: While excess weight doesn’t seem to affect early AMD risk, obesity has been linked to a 32% increased risk of developing late AMD.
Antioxidant-rich foods like fruits and vegetables buffer the harmful effects of free radicals on the eyes. Fatty fish like salmon and tuna are high in healthy fatty acids that might also be protective.
The Mediterranean diet has been investigated for slowing AMD. A
On the flip side, eating foods high on the glycemic index seems to increase the risk for AMD progression. The glycemic index is a measure of how much certain foods increase blood sugar. White bread, white pasta, and cookies are examples of high-glycemic-index foods.
According to a review in
Instead, factors like smoking and an unhealthy diet that are associated with less education may be behind the increased risk.
People who spend more time outside in the sunlight are more likely to develop AMD. Sunlight contributes to oxidative stress on the retina. Yet
Here are some lifestyle changes you can make to lower your risk for AMD and GA:
- Eat your greens: Load up on dark, leafy greens like spinach, kale, and collard greens. These vegetables contain the plant pigment lutein, a carotenoid that protects the retina against sun damage.
- Stop using tobacco: The sooner you stop smoking and the longer you stay off tobacco products, the more your AMD risk will drop.
- Work toward a moderate weight: Work with your doctor to bring down your BMI if it’s 30 or higher.
- Eat fatty fish: Salmon, tuna, and sardines are high in healthy omega-3 fatty acids that protect the eyes.
- Wear sunglasses: Look for a pair that blocks both ultraviolet A (UVA) and ultraviolet B (UVB) light.
Finally, see your eye doctor for regular checkups to head off any vision problems before they start. While you’re there, ask whether you should consider taking the AREDS vitamin formulation to lower the risk of early AMD turning into late AMD.
GA is the advanced stage of AMD. A few factors could make you more likely to develop late-stage AMD. You can’t change some factors, like your age, gender, and ethnicity, but you do have some control over your weight, diet, and sun exposure.
Your eye doctor can talk you through your AMD risks. They can also give you advice on how to preserve your vision as you get older.