Researchers report that a quick eye exam might one day allow eye doctors to check up on both your eyeglasses prescription and your brain health. A study of more than 200 people at the Duke Eye Center published March 11 in the journal Ophthalmology Retina suggests the loss of blood vessels in the retina could signal Alzheimer’s disease.
In people with healthy brains, microscopic blood vessels form a dense web at the back of the eye inside the retina, as seen in 133 participants in a control group at Duke. In the eyes of 39 people with Alzheimer’s disease, that web was less dense and even sparse in places. The differences in density were statistically significant after researchers controlled for factors including age, sex, and level of education, said Duke ophthalmologist and retinal surgeon Sharon Fekrat, MD, the study’s senior author.
“We’re measuring blood vessels that can’t be seen during a regular eye exam and we’re doing that with relatively new noninvasive technology that takes high-resolution images of very small blood vessels within the retina in just a few minutes,” Fekrat said. “It’s possible that these changes in blood vessel density in the retina could mirror what’s going on in the tiny blood vessels in the brain, perhaps before we are able to detect any changes in cognition.”
The study found differences in the retinas of those with Alzheimer’s disease when compared to healthy people and to those with mild cognitive impairment, often a precursor to Alzheimer’s disease. With nearly 6 million Americans living with Alzheimer’s disease and no viable treatments or noninvasive tools for early diagnosis, its burden on families and the economy is hefty. Scientists at Duke Eye Center and elsewhere have studied other changes in the retina that could signal trouble upstream in the brain, such as thinning of some of the retinal nerve layers.
“We know that there are changes that occur in the brain in the small blood vessels in people with Alzheimer’s disease, and because the retina is an extension of the brain, we wanted to investigate whether these changes could be detected in the retina using a new technology that is less invasive and easy to obtain,” said Dilraj S. Grewal, M.D., a Duke ophthalmologist and retinal surgeon and a lead author on the study.
The Duke study used a noninvasive technology called optical coherence tomography angiography (OCTA). OCTA machines use light waves that reveal blood flow in every layer of the retina. An OCTA scan could even reveal changes in tiny capillaries–most less than half the width of a human hair–before blood vessel changes show up on a brain scan such as an MRI or cerebral angiogram, which highlight only larger blood vessels. Such techniques to study the brain are invasive and costly.
“Ultimately, the goal would be to use this technology to detect Alzheimer’s early, before symptoms of memory loss are evident, and be able to monitor these changes over time in participants of clinical trials studying new Alzheimer’s treatments,” Fekrat said.
(Story Source: Materials provided by Duke University Medical Center. Note: Content may be edited for style and length.)
Every year I go to my primary care doctor’s office where I get a routine Medicare wellness exam that includes checking my height and weight, blood pressure and an ear and eye examination. But other than being asked to remember 3-4 words at the end of the 40-minute exam, doctors often do not check anything else for something that one in 10 seniors will face by the time they turn 65: Alzheimer’s disease (AD).
Last week, the Alzheimer’s Association released an annual report that showed only 14%–one in seven–of older adults receive regular cognitive assessments at the doctor’s office.
Almost all seniors surveyed (94%) said they had seen a personal care physician for a regular exam in the past year, but less than half (47%) said the topic of thinking or memory problems came up. A little less than third (28%) said they had ever been assessed for problems with cognition. On the other hand, seniors are routinely examined for risk factors that might lead to more serious health problems like diabetes or heart disease, for which prevention is an absolutely necessary precaution.
“[This] stands in sharp contrast to regular screening or preventive services for other health factors: blood pressure (91%); cholesterol (83%), vaccinations (80%), hearing or vision (73%), diabetes (66%) and cancer (61%),” wrote the report authors.
As people age, Alzheimer’s disease only becomes more prevalent, says Being Patient. Three percent of people age 65-74, 17% of people age 75-84, and 32% of people age 85 and older have Alzheimer’s dementia, according to research from the 2010 US Census.
Clearly, an early diagnosis of Alzheimer’s that might be caught by a simple, non-invasive eye exam could translate into huge savings for patients and the medical system. “If all individuals who were alive in 2018 and will develop Alzheimer’s disease were diagnosed during the MCI (mild cognitive impairment) stage, $7.9 trillion could be saved,” according to the Alzheimer’s Association.
Early detection allows for patients to plan for the future, participate in activities that might help preserve their cognitive function (like quitting smoking or increasing exercise) and enroll in any clinical trials that might benefit them (and future Alzheimer’s patients).
And while 93% of doctors said patients either benefit or are not harmed by early detection of cognitive impairment, more than half said that patient resistance to cognitive testing stopped them from giving an assessment.
Even though 51% of seniors surveyed said they notice changes in their cognition, just 15% said they bring up their memory concerns to their doctor on their own. Four out of five seniors said memory assessment should be a normal part of the check-up.
Both doctors and patients rank cognitive testing as important, but that belief is not yet translating to everyday care.
However, the scientific community is taking notice that tests for early detection of cognitive problems–along with the physical signs of Alzheimer’s in the brain, which appear long before symptoms–are an important part of the fight against Alzheimer’s. Over the last few years, research into everything from a smell test for Alzheimer’s to a tool that looks deep into the eyes for beta-amyloid plaques has shown promise.
And let’s not forget that Bill Gates is funding what’s called the Diagnostics Accelerator, committing $30 million to the search for a “reliable, affordable, and accessible diagnostic” for AD. Now, with this latest study from Duke, we have something on the clinical horizon much more promising to help diagnose AD far earlier than ever imagined.
Like many of you, I have come face-to-face with relatives and friends living with AD who have gradually, slowly, disappeared before our eyes. Hopefully, this simple, non-invasive eye test is what we’ve been seeking that might someday help preserve all our cognitive health for a a good deal longer than today.
It’s my sense that the such day is fast approaching.