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Eye Test for Alzheimer’s Disease

An Eye Test for Alzheimer’s Disease? How the Retina May be a Window into the Brain

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Watching an individual or loved one struggle with Alzheimer's can be heartbreaking. The gradual loss of memories, the failure to think clearly, and the eventual inability to remember who close family members are contributes to a terrifying state for the sufferer where the world seems to become smaller and smaller every day.

While there is no cure, treatments are available, and a novel new eye test for Alzheimer's disease is being pioneered to help transform the way we see this disease. Read on to learn more about the latest research surrounding the new eye test for Alzheimer's disease.

What Is Alzheimer's Disease?  

Alzheimer's is a progressive brain disease thought to result from increased amyloid and tau proteins. Amyloid proteins are thought to kill brain cells by disrupting cell-to-cell communication in the brain.

Tau proteins are critical components of the transportation system within the brain. The brain needs them to properly transmit nutrients and chemicals throughout. However, in Alzheimer's patients, the tau proteins get tangled and don't end up helping transport the necessary materials. This is also thought to play a role in the death of brain cells.

Most are familiar with the memory loss and confusion associated with Alzheimer's, but other symptoms include:

  • Depression
  • Social withdrawal
  • Mood swings
  • Irritability
  • Alteration of sleeping habits

The Eye Test for Alzheimer's Disease and the Reasoning

From a simple standpoint of distance and proximity the eyes are extremely close to the brain. This results in a high level or correlation between certain changes seen in the brain and the retina. Most notably, blood flow in the retina appears to be potentially connected to a predisposition for Alzheimer's.

Researchers at Washington University's Knight Alzheimer Research Center devised a study in which 30 participants would test the ability of current non-invasive eye diagnostic equipment to demonstrate a connection between retinal blood flow and Alzheimer's. To determine the participant's likelihood of developing the disease, a lumbar puncture and PET were performed. Seventeen participants showed elevated levels of the amyloid or tau proteins.

Next, all participants underwent the eye exams. Researchers discovered the zone in the center of the retina that contains no blood vessels was significantly larger in those at risk for Alzheimer's. While everybody has an area in the center of the retina with no blood vessels, it seems to be the enlargement of this area corresponds to changes in the brain associated with Alzheimer's.

What Are the Key Takeaways from the Eye Test for Alzheimer's?

While the prospect of an eye test that can predict Alzheimer's years before symptoms ever appear is exciting, a great deal of work needs to be done before the test can be considered diagnostic. For one thing, the study only had 30 participants, all of whom were in their 70s. This is obviously a very small research group for a very specific age. For a test like this to be of value, it needs to be able to be effective in a variety of age groups.

The ability to pinpoint preclinical Alzheimer's in individuals in their 40s or 50s, for example, would allow lifestyle changes and medication options to greatly slow the development of the disease.

Secondly, a larger study group would be necessary. Replicating the results in the study in multiple tests with participants from varied age groups would go a long way towards validating the findings that the Washington University study suggests.

Also of note is the fact the test only showed the blood vessel changes in people who were not, at the time of the study, diagnosed with Alzheimer's. The seventeen people who were at risk based on the lumbar puncture or PET scan results may never end up developing the disease. The research done to date is fascinating, but will require a great deal more before any eye test for Alzheimer's disease can be a useful diagnostic tool.

Contact Keeler Ophthalmic Instruments

For more than 100 years, Keeler has been equipping eye care professionals with a range of the best and most effective ophthalmic instruments, including:

We pride ourselves in delivering the best high quality sight testing equipment, so eye care professionals can deliver the highest level of service to their patients.

Contact Keeler Ophthalmic Instruments today.

About the Author Eugene VanArsdale

Eugene is the Director of Marketing Communications at Keeler Instruments. He has been with Keeler since 1982 and is co-holder of two patents for the company. Eugene has a true passion for the eye care industry and has dedicated himself to understanding the ins and outs of the optometric and ophthalmic equipment market.