Eye Exams May One Day Detect Alzheimer's Disease

Megan Ray  |  August 8, 2014

There are plenty of good reasons to get your eyes checked regularly, and research presented at a recent meeting in Copenhagen may provide another surprising incentive. According to a report presented at the Alzheimer's Association International conference, doctors may soon be able to detect the early signs of Alzheimer's disease with a simple eye test.

Beta-amyloid plaques have long been linked to Alzheimer's, with more of the substance appearing in people's brains as the disease progression. For the first time, researchers have demonstrated that beta-amyloid may be detectable without expensive brain testing and before enough of the plaques appear to cause serious damage. The report's authors said that the experimental eye test could detect the early signs of Alzheimer's much sooner.

Importance of early detection 
According to The Guardian, late detection is one of the major problems hampering the advancement of Alzheimer's care. By the time most people are diagnosed with the disease, it's too late to take many effective steps toward alleviating its symptoms, let alone slowing its progression. Even in clinical trials, many medications have been rejected as possible treatments, since the brains of people taking them have suffered too much damage from Alzheimer's for the drugs to be effective.

Other amyloid tests are too complex
Amyloid levels can be measured with a number of tests, but researchers said that they are too expensive to be used as early detection systems. Brain scans using chemicals that make the beta-amyloid protein visible are used in some cases when Alzheimer's is suspected, but the test is too expensive - and the equipment and expertise too rare - for it to be a viable option for many people. Fluid from the spinal cord can also be tested for the presence of beta-amyloid, but the procedure is invasive.

New exam methods
The eye test proposed by researchers would be both easy and inexpensive to perform. Two potential methods for such a test were presented at the AAIC, both of which were successful in initial trials. One method involved participants ingesting curcumin, commonly found in the spice turmeric, which binds to amyloid proteins. Using a special imaging device, researchers could then detect any beta-amyloid in the eye. In the study, Alzheimer's was detected in 100 percent of the people who had it. Only about 20 percent of those who didn't have the disease received a false positive result.

Another research team had participants apply an ointment to the inside of their eyelids the night before an eye test, which the researchers said had no negative effects. The next day, a laser scanning device was able to detect amyloid proteins that the ointment revealed. This test found the illness in 85 percent of participants who had Alzheimer's, and falsely identified only 5 percent of people without the disease.

Using either method, the amount of beta-amyloid plaques the eye tests were able to pick up matched the amount found in the brain, suggesting that the results were reliable. Researchers said that the tests were simple and uninvasive enough that they may be able to some day become a part of routine eye exams. However, further study will be needed before that stage.

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