A new study by a team of scientists at Cedars-Sinai Medical Center has shown that early signs of Alzheimer’s could be detected by a noninvasive retinal scan. Led by Dr. Maya Koronyo-Hamaoui and Dr. Yosef Koronyo, the study demonstrates that a simple retinal scan can identify Alzheimer’s patients, who are are more likely to develop brownish amyloid plaques, or deposits of toxic protein, on their retinas. Doctors are currently able to identify amyloid plaques through PET scans and cerebrospinal fluid (CSF) analysis, but these methods are time-consuming and expensive.
Using new technology created by biotechnology company NeuroVision, the scientists on the research team have found that Alzheimer’s could be detected with a retinal scan 10 to 20 years before the onset of severe symptoms. The technology uses a combination of autofluorescence imaging and a high-tech ocular camera to create an image of the retina. The scans are then processed on special imaging software to isolate the distinctive brown spots of amyloid plaques. The study also found that the buildup of amyloid plaques in the retina corresponded with a similar buildup in the brain. Due to its close connection with the brain, the retina can serve as a valuable early warning indicator of Alzheimer’s. The team’s scanning technology is not currently available commercially, but they hope that one day their new method will be used to screen and diagnose patients with Alzheimer’s before other symptoms begin to appear.
Earlier this year, a study from the University of Pennsylvania School of Medicine showed that noninvasive retinal scans may also help detect the cognitive disorder frontotemporal dementia. Study participants with frontotemporal dementia exhibited a thinning of their outer retinal layers. The study identified increased thinning in the external nuclear layer and the external filamentous zone of the retina. Scientists were able to detect this thinning by using spectral domain optical coherence tomography (SD-OCT), a noncontact imaging technique. Unlike other tests commonly used to diagnose cognitive disorder frontotemporal dementia, SD-OCT scans are quick and cost-effective.