What's the Link Between Dementia and Age-Related Macular Degeneration?

Both age-related macular degeneration (AMD) and dementia, including Alzheimer's disease, are linked to the aging process. Researchers have been increasingly wondering if these diseases may be related since they have some features in common.¹

What is dementia and Alzheimer's disease?

Dementia is not a disease. Instead, it is a group of symptoms that show changes in behavior, such as anxiety, depression, and personality changes. It also impacts how the brain functions, leading to symptoms like confusion, difficulty reasoning, trouble communicating, and loss of memory.²

Many diseases can cause dementia, such as Parkinson's disease, traumatic brain injuries, brain tumors, and Huntington's disease. Dementia is not limited to older adults, since it can be caused by many factors. But the risk of dementia does increase with age.^1-3

Alzheimer's disease is a progressive brain disease that is the most common cause of dementia. It is characterized by clumps of proteins known as amyloid plaques that are found in the brains of people with Alzheimer's. Most people show memory loss in the early stages of the disease. They begin to show other symptoms of dementia as the disease progresses.³

In rare cases, Alzheimer's can happen in younger people. Early-onset Alzheimer's is defined as showing symptoms before the age of 65. The youngest cases happen to people under the age of 40. It is more common in people over the age of 65.³

There is currently no cure for Alzheimer's. But early intervention and treatment can help people and their families manage the symptoms of the disease.

What is age-related macular degeneration?

AMD is an eye disease that occurs when the part of the eye that is responsible for sharp, central vision is damaged. This area is known as the macula. It is part of the back of the eye, or retina.⁴

As the damage to the macula progresses, people lose their central vision and may develop blurry, dark, or blank spots in the center of their field of vision. AMD is the leading cause of vision loss in people over the age of 55. While AMD does not cause complete blindness, it can greatly interfere with everyday activities.⁴

Risk factors for AMD include:⁴

• Age
• Smoking
• Genetics
• Race, with white people having the highest risk

There is currently no cure for AMD. But doctors can offer treatments to help slow disease progression and reduce AMD symptoms.

How are these diseases related?

Researchers have noticed that AMD and Alzheimer's have factors in common. While both diseases are related to age, they are also related to protein deposits and the breakdown of certain brain cells.⁵

In one study, people with AMD also were more likely to have trouble with thinking and communicating well compared to people without AMD. Researchers looked at the medical records of 580 people with and without Alzheimer's. They found that twice as many people had AMD than people who did not have Alzheimer's. Another study of 3,800 people found that those with AMD were 20 percent more likely to get Alzheimer's than those without AMD.^1,5

While doctors are not sure why these diseases are linked, they do recognize that there is some relationship between AMD and Alzheimer's. Researchers are now questioning if we can use this relationship to make earlier Alzheimer's diagnoses.^6,7

Early diagnosis is important in potentially slowing Alzheimer's progression. This relationship between AMD and Alzheimer's may also lead to better treatments. While researchers continue to make new discoveries about both Alzheimer's and AMD, discoveries such as this can help pave the way to better care for both diseases.