Alzheimer’s Disease is the most common form of dementia, impacting more than 44 million people worldwide. While there is no cure, early detection and diagnosis is key to managing the condition and delaying symptoms for as long as possible.
The results from two studies presented at the annual meeting of the American Academy of Ophthalmology show that an eye scan from a new imaging device may be an easy and non-invasive way of detecting Alzheimer’s in patients within seconds. Researchers said the small blood vessels in the retina at the back of the eye are altered in patients with Alzheimer’s – even in patients with a family history of the disease without any visible symptoms.
The imaging process, known as optical coherence tomography angiography (OCTA), has been used in recent research to draw a connection between the eye and Alzheimer’s, allowing physicians to see the smallest veins in the back of the eye, such as red blood cells moving through the retina. Researchers believe that because the retina is connected to the brain through the optic nerve, the deterioration in the retina and its blood vessels could mirror changes occurring in blood vessels and structures of the brain. As such, this could offer researchers an insight into the disease process.
At present, detection of Alzheimer’s isn’t easy due to high cost of brain scans and potential harm spinal taps can cause. Many cases are diagnosed through memory tests or observed behaviour changes, but the disease is usually in its advanced stages by this point. Researchers believe future treatments will work if Alzheimer’s is detected early, while early diagnosis allows patients and their families to prepare for the future.
For the study, researchers from Duke University used OCTA to compare the retinas of Alzheimer’s patients to those of people with both cognitive impairment as well as those with healthy brains. They discovered those with Alzheimer’s had loss of small retinal blood vessels at the back of the eye, as well as a thinner layer of the retina. These changes weren’t present in healthy participants or even those with cognitive impairment.
“This project meets a huge unmet need,” lead author Sharon Fekrat said in a statement. “It’s not possible for current techniques like a brain scan or a lumbar puncture (spinal tap) to screen the number of patients with this disease.
“Almost everyone has a family member or extended family affected by Alzheimer’s. We need to detect the disease earlier and introduce treatments earlier.”
In a separate study, researchers from the Sheba Medical Center in Israel examined 400 people who had a family history of Alzheimer’s, but showed no symptoms. Researchers compared patients’ retinas and brain scans to people with no family history of Alzheimer’s and found that similar to the Duke University study, those with a family history had a thinner inner layer of the retina.
The brain scan also showed the area of the brain first impacted by the disease had already began to shrink in those with a family history.
“A brain scan can detect Alzheimer’s when the disease is well beyond a treatable phase,” leader researcher of that study Ygal Rotensteich said. “We need treatment intervention sooner. These patients are at such high-risk.”