Macular degeneration is a loss of central vision due to damage to part of the retina. Genetics, lifestyle, and environmental causes are all risk factors for developing the disease.

People may refer to the condition as age-related macular degeneration (AMD or ARMD) as it usually affects older adults. AMD is the main cause of vision loss in people aged 50 or above.

In the United States, almost 2 million people have AMD, and the condition is the leading cause of irreversible vision loss. Experts estimate this figure may double in the next 20 years.

This article explains macular degeneration, its causes and risk factors, and whether it is hereditary.

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AMD is the loss of the central part of a person’s vision. This means people have normal peripheral vision but will not be able to see fine details in front of them, whether near or far away.

The macula is part of the retina that allows people to see straight ahead with sharp, clear vision. Damage or deterioration to the macula can lead to macular degeneration.

There are two types of AMD:

Dry or atrophic AMD

Dry AMD occurs when the macula becomes thinner as people age and small clumps of a protein deposit — drusen — collect underneath the retina. Dry AMD is the most common type, affecting around 80% of people with the condition.

Vision loss with dry AMD occurs gradually and in stages. It may progress over several years. There is currently no treatment for the later stages of dry AMD, but if it is only present in one eye, people can take measures to protect the other eye.

Wet AMD or advanced neovascular AMD

Wet AMD is a late stage of the condition and is less common. Dry AMD can turn into wet AMD.

It occurs when there is an abnormal growth of blood vessels at the back of the eye, which causes damage to the macula. Wet AMD can result in more rapid vision loss, but treatment is available for it.

Learn more about wet vs. dry AMD here.

According to the BrightFocus Foundation, genetics may play a part in AMD development in around 3 out of 4 cases.

Certain genes can increase the risk of developing AMD. Two genes — Factor H and Factor B — play a role in regulating inflammation within the immune system.

In 74% of people with AMD, these genes have certain variants that may link to an increased risk of developing the condition.

Other genes that can play a role in the development of AMD include:

  • the PLEKHA1 gene on chromosome 10
  • a variation of the LOC387715 gene, particularly if a person also smokes
  • a mutation in the HTRA1 gene
  • complement C3 variant

There are over 30 genes that have an association with a risk of developing AMD.

In particular, two genes that may have a close connection with AMD and how it progresses are the complement cascade, part of the immune system, on chromosome 1, and the ARMS2/HTRA genes on chromosome 10.

If people have these particular gene variants, they may have a higher risk of developing AMD.

There are also certain variants of genes that can have a protective effect against AMD and may lower the risk of developing it.

Although genetics can play a part, research suggests a combination of factors can contribute to AMD. These include:

Other factors that may contribute to the development of AMD include:

  • Cigarette smoking: In a study of female smokers, those who smoked 25 cigarettes or more per day had a significantly increased risk of AMD compared with those who had never smoked. Around 29% of AMD cases in the study had a link to smoking.
  • Nutrition: Higher intake of saturated and trans fats increases the risk of AMD progressing to advanced stages of the disease.
  • Obesity: This has a significant association with an increased risk of AMD progression.
  • Cardiovascular risk factors: Higher inflammatory markers related to cardiovascular risk may also signal AMD risk.

Risk factors for developing AMD also include:

Below, we answer some commonly asked questions about macular degeneration.

Does macular degeneration always run in families?

Although a family history of AMD increases the risk of developing the condition, lifestyle and environmental factors also play an important part.

If people have a family history of AMD, taking the following steps may help to reduce the risk of developing the condition:

  • avoiding smoking
  • exercising regularly and staying physically active
  • maintaining blood pressure and cholesterol levels within a healthy range
  • eating a healthy, balanced diet including dark green leafy vegetables and fish, and limiting saturated fat

Can I get a test for macular degeneration?

People can see an eye doctor to test for AMD. An eye doctor will carry out a dilated eye exam by giving people eye drops to dilate the pupil to examine it for any disorders.

Another test is an optical coherence tomography (OCT) test, in which an eye doctor will take images of the inside of the eye using a special machine.

If people have a family history of AMD or other risk factors, it is important for them to attend regular eye exams.

What are the early warning signs of macular degeneration?

Early AMD may not cause any symptoms. People can notice the following mild symptoms in the intermediate stages of AMD: Some blurriness in their central vision and difficulty seeing in low lighting.

In the later stages of dry AMD, or with wet AMD, people may experience:

  • straight lines appearing as crooked or wavy
  • a blurry area or blank spots in the center of their vision
  • colors appearing less bright
  • difficulty seeing in low lighting

People will need to contact a doctor if they have any symptoms of early or late AMD.

Outlook for AMD may depend on the type and stage of the disease. Although there is currently no cure for dry AMD, certain vitamins in foods or supplements may help to slow down or prevent disease progression, such as:

  • lutein
  • zeaxanthin
  • omega 3
  • zinc
  • vitamin C
  • vitamin E

If people have wet AMD, treatment may help to prevent further vision loss, such as:

  • anti-VEGF medications, which a doctor injects into the eye
  • photodynamic therapy, which is a combination of laser treatment and injections

Learn about 10 foods for eye health here.

Macular degeneration is a common eye disease in people over 50. It occurs due to damage to the macula, part of the retina, and causes a loss of central vision.

Certain genes can increase the risk of the disease, along with lifestyle and environmental factors, such as smoking, high cholesterol, and blood pressure, and eating a diet high in saturated fats.

If people have a family history of macular degeneration, getting regular eye exams, staying physically active, and eating a balanced, healthy diet may all help to reduce the risk of developing the condition.