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Using the Retina for Early Diagnosis of Alzheimer's Disease

We all know that regular health checks are an important part of staying healthy, but what about our eyes? It turns out that many diseases present signs and symptoms that affect the eyes, including diabetes, cardiovascular disease, renal disease, digestive conditions, and even some cancers can leave clues in the eyes. Scientists and doctors alike are starting to take advantage of this discovery to detect and treat these diseases earlier. And none are more exciting and impactful as using the eyes to diagnose Alzheimer’s disease.

 

For a rundown of this new breakthrough that the eyes are the window to our health, we looked to Michael Bagley, alumnus of our citizen science lab that is currently an Optometric Intern at Pacific University College of Optometry. Thanks to Michael for sharing these insights with us!

 

Cheers,
Nicole

 

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A New Vision on Alzheimer’s Disease Testing

 

Researchers at Cedars-Sinai Medical Center developed a non-invasive eye exam that looks for signs of Alzheimer’s disease in the retina. A team at the Commonwealth Scientific and Industrial Research Organization (CSIRO) then conducted a human trial to determine if what they saw in the retina of patients enrolled in the study did in fact reflect the health of the brain.

 

Their results are promising; by looking at the eyes, doctors in the very near future may have a non-invasive way to determine the progression of Alzheimer’s on the brain.  

 Eyes

 

The reason why this development is so impactful has to do with how Alzheimer’s disease is currently diagnosed. Traditionally, plaques in the brain are discovered through Proton Emission Tomography (PET) scans. These plaques are due to a buildup of a protein called, beta-amyloid, around brain cells (neurons). The accumulation of the plaques plays a role in causing the neurons to die. As more and more of these brain cells die, the disease progresses, causing increased complications with memory and cognition. 1 These scans expose the patient to high levels of radiation, are lengthy, and expensive. Worse over, plaques usually aren’t detectible until the disease has already progressed into the later stages. 

 

Image 1 

PET scans showing Alzheimer’s disease on the left, compared to a healthy adult brain on the right. The hotter colors, like yellow and red, indicate higher presence of amyloid plaques.

Image credit: University of Pittsburgh Medical Center, click image to be directed to original source.

 

 

 

This is where the eyes come in, literally extensions of the brain. The new test searches for those same beta-amyloid plaques in the retina. Using curcumin (a component of turmeric) and a high resolution imaging (called Retinal Amyloid Imaging or RAI), the scientists can distinguish the plaque affected cells from healthy retina cells.3, 5 The most promising part of this test is that the research suggests that the plaques can be found 15-20 years before a clinical diagnosis is possible through conventional methods like PET. 2 This could be a game changer for early diagnosis of Alzheimer’s disease. A larger study, involving 200 patients, is expected to be completed by the end of 2014.4

 

 

Image 2 

 

The curcumin binds to amyloid plaques, an indicator of Alzheimer's disease. Using RAI, the curcumin lights up as littel pink/red dots.

Image Credit: CSIRO, click image to be directed to original source

 

 

 

Through the dedication of institutions like CSIRO and Cedars-Sinai Medical Center, we have a lot to look forward to in the future of Alzheimer’s Disease and ocular imaging. As in any disease, the early detection of Alzheimer’s will lead to earlier treatments and therefore better outcomes and prognoses for patients. Already, there is so much the eyes can show about the health of an individual. If you have any questions or concerns, consult your optometrist or health care provider.

 

Michael A. Bagley, Optometric Intern
Pacific University College of Optometry

 

References

 

  1. Alzheimer's Association. (2011). Alzheimer's Disease and the Brain. Retrieved from http://www.alz.org/braintour/tangles.asp
  2. American Optometric Association. (2014, July 15). Could eye imaging help detect Alzheimer’s earlier?  Retrieved from http://www.aoa.org/news/eye-care-advances/could-eye-imaging-help-detect-alzheimers-earlier?sso=y
  3. Chirgwin, R. (2014, July 15). Get an EYEFUL OF CURRY for the sake of your brain • The Register. Retrieved from http://www.theregister.co.uk/2014/07/15/get_an_eyeful_of_curry_for_the_sake_of_your_brain/
  4. Center, C. (2014, July 14). "Noninvasive retinal imaging device may provide highly predictive early detection of changes associated with Alzheimer's disease." Medical News Today. Retrieved from
    http://www.medicalnewstoday.com/releases/279566.php.
  5. Alzheimer's Association. (2014). Smell and eye tests show potential to detect Alzheimer's early. Retrieved from http://http://www.alz.org/aaic/releases_2014/sun-830am-smell-eye-tests.asp
  6. Pelino, C. J., & Pizzimenti, J. J. (2011, April). Ocular manifestations of systemic disease. Retrieved from http://http://www.revoptom.com/continuing_education/tabviewtest/lessonid/107561/

 

 

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