Could looking into the eyes aid stroke diagnosis?

Table of Contents

  1. Blood-brain barrier and blood-ocular barrier
  2. Stroke can disrupt blood-ocular barrier
  3. Gadolinium leakage and stroke severity

Scientists have made a surprising discovery about the eye and its blood supply that may help to improve the diagnosis and treatment of stroke.
woman getting eye testCould our eyes hold the key to better stroke treatment?

In a paper that was recently published in the journal Neurology, they describe how they found that a contrast agent that is given to stroke survivors in order to highlight brain abnormalities can also leak into the eyes.

Senior study author Dr. Richard Leigh, who is an assistant clinical investigator from the National Institute of Neurological Disorders and Stroke — which is one of the National Institutes of Health (NIH) — states that he and his colleagues were “kind of astounded” by the discovery, and that “it’s a very unrecognized phenomenon.”

“It raises the question,” he continues, “of whether there is something we can observe in the eye that would help clinicians evaluate the severity of a stroke and guide us on how best to help patients.”

A stroke occurs when a part of the brain loses its life-giving blood supply, either due to a blockage (ischemic stroke) or a rupture (hemorrhagic stroke) in a blood vessel. Most strokes are ischemic.

Stroke used to be the fourth leading cause of death in the United States, but — thanks to medical improvements — it is now the fifth. Prompt medical care following a stroke can not only save lives, but it also improves quality of life for survivors.

More than 795,000 people every year have a stroke in the U.S., where the total annual cost of healthcare, drugs, and missed work days associated with the condition comes to around $34 billion.

Blood-brain barrier and blood-ocular barrier

When people are admitted to hospital following a stroke, they will usually undergo an MRI scan to assess the damage to the brain. Often, this involves having an injection of a contrast agent called gadolinium, which is a harmless substance that travels to the brain and lights up any abnormal areas on the scan.

In healthy people, the blood-brain barrier usually stops the contrast agent from getting into the brain tissue. It stays in the bloodstream and is eliminated through the kidneys.

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The blood-brain barrier, a thin layer of highly active tissue that lines the tiny blood vessels that feed the various parts of the brain, prevents potentially harmful substances from crossing over from the bloodstream.

But a stroke can damage the tiny blood vessels and cause leakage in the blood-brain barrier, which allows some gadolinium to leak into the brain tissue. This shows up as bright spots on MRI scans.

Between the eyes and the bloodstream, there is a similar barrier called the blood-ocular barrier. There is evidence from previous studies that some eye diseases can disrupt the blood-ocular barrier.


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