Causes and Risk Factors of Macular Degeneration

The exact cause of macular degeneration, often called AMD or ARMD (age-related macular degeneration), is not known—a frustrating fact for patients and doctors alike, as the condition is the leading cause of vision loss and blindness in Americans aged 65 and older. That said, there are known risk factors for AMD—some of which you can have an influence on, like smoking, obesity, and sun exposure, and others that you cannot, such as age and genetics.

Common Risk Factors

macular degeneration risk factors
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Advancing Age

Age is the most significant risk factor for macular degeneration. About 1 percent of white adults ages 60 to 69 have the condition, but that jumps to 14 percent in those age 80 and older.

Gender

Studies have shown that you have a slightly higher risk of developing macular degeneration if you are a woman.

There seems to be a link between the onset of menopause and macular degeneration. Women who have early onset menopause also develop macular degeneration sooner. In fact, there is research investigating the role of estrogen in macular degeneration treatment.

Also, because women tend to live longer, they are at higher risk of experiencing severe vision loss when diagnosed with AMD than men with the condition, as it progresses with time.

Genetics

Macular degeneration is not reliably passed down, but hereditary factors can play a role.

Family History

Having a family history of age-related macular degeneration has been shown to increase your risk by 50 percent. If you have family members with macular degeneration, you should pay particular attention to other risk factors and be sure to go for regular vision checks.

Race

Age-related macular degeneration is the leading cause of blindness in aging white Americans. The disease is relatively rare among people of other races, but it can occur.

Eye Color

Although it's not known exactly what causes the disease, the amount of pigment present in the tissue of the eye may play a role. People who have light eye color appear to be at greater risk of macular degeneration than people who have darker eyes.

Stargardt’s Disease

Stargardt’s disease is the most common form of juvenile macular degeneration, affecting 1 in 10,000 children in the United States. 

In Stargardt’s disease, there is a genetic defect that causes the photoreceptors of the eye to die. Vision loss begins slowly and then rapidly progresses, affecting central vision so severely that it causes an affected person to become legally blind while preserving peripheral vision. 

It can be diagnosed as early as 6 years of age and is usually noticeable before age 20. It is possible to have the disease and not know it until you are almost 40. The condition affects males and females equally.

Vitelliform Macular Dystrophy and Best Disease

The second most common form of juvenile macular degeneration is Vitelliform macular dystrophy, also referred to as Best disease when it begins before age 6. 

Vitelliform macular dystrophy is a hereditary condition that begins at a much younger age than Stargardt’s disease. Vision loss may or may not occur in the early stages. It is diagnosed by the observation of yellow, fatty tissue in the macula, which are detected on eye examination.

Health Conditions

High Blood Pressure and Heart Disease

Hypertension and other cardiovascular diseases and conditions increase the likelihood of developing macular degeneration. Macular degeneration is associated with substantial vascular changes in the eye, and it is believed that the factors that contribute to heart disease and hypertension may also contribute to macular degeneration. 

Obesity

Being overweight is not only associated with developing age-related macular degeneration but severe forms of the condition, such as geographic macular degeneration and neovascular macular degeneration, though the reason why is not concrete.

Lifestyle

Some lifestyle factors have been associated with the development of macular degeneration:

Smoking

Research shows that smoking increases the risk of macular degeneration. The exact reason for this is not clear, but smoking increases the risk of vascular disease in general, and blood vessel abnormalities are a major part of the disease process in macular degeneration. 

Sun Exposure

Spending too much time in the sun without ultraviolet protective sunglasses appears to speed the development of macular degeneration. Researchers have discovered that people with histories of prolonged, unprotected exposure to sunlight had more cases of severe macular degeneration than those without such exposure.

Diet/Nutrient Deficiency

Antioxidants may protect your cells from oxidative damage, which is partially responsible for many of the effects of aging, including macular degeneration. If you have low levels of antioxidant vitamins and minerals such as zinc, vitamin A, vitamin C, and vitamin E, you might have a higher risk of developing vision loss related to macular degeneration.

Studies also show that people with a high-fat diet are twice as likely to develop wet macular degeneration, which is the advanced form of the condition.

Sources:

DeAngelis MM, Owen LA, Morrison MA, et al. Genetics of age-related macular degeneration (AMD). Hum Mol Genet. 2017 Aug 1;26(R1):R45-R50. doi: 10.1093/hmg/ddx228.

Kim EK, Kim H, Vijayakumar A, Kwon O, Chang N. Associations between fruit and vegetable, and antioxidant nutrient intake and age-related macular degeneration by smoking status in elderly Korean men. Nutr J. 2017 Dec 4;16(1):77. doi: 10.1186/s12937-017-0301-2.

Myers CE, Klein BE, Gangnon R, Sivakumaran TA, Iyengar SK, Klein R. Cigarette smoking and the natural history of age-related macular degeneration: the Beaver Dam Eye Study. Ophthalmology. 2014 Oct;121(10):1949-55. doi: 10.1016/j.ophtha.2014.04.040. Epub 2014 Jun 20.

National Eye Institute. Age-Related Macular Degeneration (AMD). 2010. https://nei.nih.gov/eyedata/amd

Woo SJ, Ahn J, Morrison MA, et al. Analysis of Genetic and Environmental Risk Factors and Their Interactions in Korean Patients with Age-Related Macular Degeneration. PLoS One. 2015 Jul 14;10(7):e0132771. doi: 10.1371/journal.pone.0132771. eCollection 2015.

Xie J Ikram MK Cotch MF et al. Association of Diabetic Macular Edema and Proliferative Diabetic Retinopathy With Cardiovascular Disease: A Systematic Review and Meta-analysis. JAMA Ophthalmol. 2017 Jun 1;135(6):586-593. doi: 10.1001/jamaophthalmol.2017.0988.