A simple eye test could soon reveal whether you have Alzheimer’s Disease - or even if the disease looms in your future. In fact, according to trial results released this week, the vision test detected signs of Alzheimer’s 15 to 20 years before the appearance of clinical signs.
This potentially game-changing news comes out of the Alzheimer's Association International Conference, currently ongoing in Copenhagen, Denmark, where two presentations highlighted the potential of new vision screening technologies that use retinal imaging to measure amyloid plaque formation in the back of the eye.
The technology is based on an astoundingly simple idea: The brain-clogging amyloid plaques considered an indicator of Alzheimer’s can also be seen in the back of the eye, which is considered a mirror for brain health. "If this test works, then one day screening for Alzheimer's disease may be as simple as getting your eyes checked," said Yogi Kanagasingam, one of the researchers conducting clinical trials.
The first test, from Neurovision Imaging of Sacramento, California, utilizes retinal image fluorescence photography to scan the supranucleus region of the retina for a fluorescent signature characteristic of beta amyloid plaques. In preparation for the scan, participants take curcumin, the ingredient in turmeric that gives the spice its fluorescent yellow color, to “light up” the amyloid plaques with a specific fluorescent signature.
Preliminary data released on 40 trial subjects showed that levels of amyloid in the retina correlated closely with amyloid levels in the brain as revealed by PET (positron emission tomography) scans, the current detection method of choice.
The retinal imaging was also able to tell subjects with Alzheimer’s from those without the disease with 100 percent sensitivity and 80.6 percent specificity. Neurovision is working with Australia’s Edith Cowan University McCusker Alzheimer’s Research Foundation to test their retinal imaging scan.
NeuroVision isn’t alone in the retinal imaging field; a second data presentation, this time from Massachusetts-based Cognoptix, also showed promising results from another pioneering technology. Cognoptix's SAPPHIRE II technology utilizes a fluorescent ligand eye scanning (FLES) process in which a topical ointment applied to the lens of the eye binds to beta-amyloid. The plaques are then detected with a laser scanner.
The Cognoptix clinical trial data, published in February in the Journal of Alzheimer's Disease and Other Dementias, involved 40 participants and predicted Alzheimer’s with 85 percent sensitivity. It differentiated participants with Alzheimer's from those without the disease with 95% accuracy.
A retinal imaging test for Alzheimer's, if it proved accurate, could drastically change the way Alzheimer’s is diagnosed. “Presently the tests that are used in clinical trials are PET scan of the brain and CSF via lumbar puncture to measure levels of amyloid and tau," says CEO NeuroVision CEO Steven Verdooner. "Our retinal imaging test is expected to be meaningfully less expensive than a PET scan, is noninvasive, and potentially more sensitive.”
Early detection of Alzheimer's disease is a key goal of current research because the treatments currently available to slow the progression of the disease are much more effective if started early.
What’s more, because a retinal imaging test is relatively simple to take and without major longterm health effects, it could be re-administered regularly to monitor the progress of the disease. “We believe the ability to measure progression is very powerful and are engaging in partnerships for therapeutic trials to prove that out,” says Verdooner.
Right now, because PET scans are radioactive, doctors don’t like to repeat them multiple times and usually wait at least 18 months before administering a second PET scan. According to Verdooner, Neurovision’s test can be repeated after an interval as short as three months.
While a vision test for Alzheimer’s isn’t going to be commercially available anytime soon, the wait isn’t going to be as long as you might think, either. The current trial winds up in the fall, at which point Neurovision will begin working with academic institutions to continue validating the retinal imaging procedure.
NeuroVision's test could be available as soon as the second half of 2015, Verdooner says. “Once commercialized, we expect it to be available in doctors’ offices and can be administered by request from the patient or a referring doctor.”
The retinal imaging test will be administered as part of a package, along with blood-based biomarkers and cognitive screening, Verdooner says. “The paradigm we’re aiming at is a battery of tests that is cost-effective, fast, and non-invasive.”