The eyes might be the window to the soul, but they can offer surprising insights to your health, too. A new take on an old eye exam may be able to tell if someone has Alzheimer’s disease.
An imaging technique called OCT angiography, which takes pictures of blood vessels and nerves in the back of the eye, may be able to detect early Alzheimer’s disease. Researchers have found that similar vascular changes occur in the retina and the brain during the development of Alzheimer’s disease. Could OCT angiography be a quick, safe and effective alternative for early detection of Alzheimer’s disease?
Researchers at Duke University compared retinal scans of over 200 people to compare blood flow using an imaging technique called OCT angiography. The technique creates in-depth, high-resolution pictures of the back of the eye and color-codes blood flow. Red and orange areas are rich in blood vessels, while blue and green areas are more scarce.
The Duke University researchers examined 39 people with Alzheimer’s disease, 72 with mild cognitive impairment and 133 control volunteers. The Alzheimer’s patients showed changes in their retinal blood vessels, with reduced blood flow to parts of their central vision. They also had areas in common where the retina had atrophied or thinned.
The retina is the layer of tissue in the back of the eye that contains cones and rods, cells that are sensitive to light and make it possible for us to see. Reduced blood flow can lead to loss of visual acuity. Doctors can easily detect this by dilating the eyes, focusing a specialized camera past the dilated pupils and taking images of the retina.
Changes in the small blood vessels in the brain often precede the mental decline we associate with Alzheimer’s disease. Brain imaging can’t always detect these changes, so the first indications someone has the disease are often behavioral ones. Studies have found retinal and brain tissues, both components of the central nervous system, undergo similar vascular effects during dementia development. Imaging the blood vessels in the brain might not be easy, but taking a picture of someone’s retina is.
A safe, quick and effective test for early Alzheimer’s disease could soon be as simple as going in for an eye exam. Even better, it may be able to diagnose the disease long before any other symptoms show. Earlier diagnosis could mean earlier interventions, and research on how the disease develops may lead to more effective future treatments.
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