A research team led by the Keck School of Medicine of the University of Southern California (USC) has discovered that a non-invasive eye exam may be a possible tool for screening Black Americans and other people from underdiagnosed and high-risk populations for cerebral small vessel disease, a major contributor to cognitive impairment and dementia. After Alzheimer’s disease, vascular dementia, associated with impaired blood flow to the brain, is the second most common dementia diagnosis.
Using a new type of device that looks at the blood vessels in the retina, the team was able to connect certain characteristics in the vasculature of the eye to early signs of cognitive decline and structural changes commonly found in the brains of people with cerebral small vessel disease.
Recruited from the African American Eye Disease Study, a population-based study of more than 6,000 African Americans from Inglewood, California, the research participants were all over 40 and had no history of cognitive impairment. Study participants underwent a type of retinal imaging called optical coherence tomography angiography, or OCTA, which was carried out at USC.
OCTA, a relatively new type of imaging that is increasingly incorporated in clinical practice in ophthalmology, captures detailed images of tiny retinal capillaries without needing to inject a dye into the patient. Using these images, the team was able to calculate the density of these blood vessels within the retina, the amount of blood that is flowing through those vessels and how quickly the blood was moving.
Among people in the study who underwent cognitive testing, lower rates of blood flow and blood vessel density were connected to worse information processing speed and executive function.