New therapy for eye stroke

At first, Christine Jablonski didn8217;t worry about the blurry vision in her right eye. She dismissed it as a flake of mascara and went about work.

At first, Christine Jablonski didn8217;t worry about the blurry vision in her right eye. She dismissed it as a flake of mascara and went about work. But within two hours, the eye went dark. She rushed to Johns Hopkins Hospital, where doctors told her there was nothing they could do to restore her vision. She had suffered an 8220;eye stroke8221; from a clot blocking a key blood vessel that supplies the retina.

But her daughter, a doctor, had heard about an experimental treatment pioneered by doctors at Hopkins8217; Wilmer Eye Institute. The hospital8217;s Brain Attack Team 8212; a group of physicians who specialise in strokes of the brain, was called in. They ran a catheter all the way from Jablonski8217;s groin to her eyeball and injected a clot-busting agent.

8220;I could see my vision coming back. It was like a curtain of color,8221; Jablonski said. Within two hours, her eyesight had returned to normal. Her experience and reports of success with other volunteers in a seven-year Hopkins study raise hopes for as many as 50,000 people who suffer eye strokes each year and would otherwise face irreversible loss of sight in one eye.

But Hopkins doctors caution that the experimental procedure carries its own serious risks and success seems to depend on treating the patient into as soon as possible. It didn8217;t work at all on almost 25 per cent of patients in the study, and other authorities say more trials are necessary before they can recommend the procedure. Still, the Hopkins team was heartened by the results: Their volunteers were 13 times more likely than those undergoing conventional therapies to show significant improvement with standard eye charts. And they were almost five times as likely to achieve a final visual acuity of 20/100 or better on a 20/20 scale.

8220;We have a disorder that was basically irreversible, but with our technique, we see that a majority of patients experienced some level of improvement in their vision,8221; said Dr Eric Aldrich, neurologist at the School of Medicine and lead author of a study published in the June issue of Stroke. 8220;No one has ever reported these types of results on such a large scale in North America.8221;

WHAT IS EYE STROKE

An eye stroke, technically known as a central retinal artery occlusion, occurs when a clot forms in a small blood vessel within the eye. The interruption of blood flow destroys the retina, the light-sensitive nerve layer that captures images. The attack is sudden, painless, but it causes partial or complete vision loss in one eye. The other eye is usually unaffected.

Eye stroke is more likely to occur in the elderly, Hopkins researchers said. The condition appears to have the same heightened risk factors as brain stroke and heart disease. Those include diabetes, high blood pressure, elevated cholesterol levels, smoking and a family history of cardiovascular problems.

THE PROCEDURE

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Under Aldrich8217;s direction, a team of ophthalmologists, radiologists and neurologists developed a scheme to insert tissue plasminogen activator TPA, a clot-dissolving agent, into an artery near the eye. They start by inserting a catheter into the patient8217;s femoral artery in the thigh. Then, using an X-ray video display to show the way, they thread the tube up the bloodstream to the eye, where they administer TPA by drip until the blood clot dissolves.

From 1999 to 2006, 21 patients received TPA, while another 21 in their study received conventional therapies. Overall, 76 per cent of the TPA group improved their vision by at least one line on the Snellen chart 8212; the eye chart with the big 8220;E8221; at the top. Only 33 per cent in the standard therapies group showed as much improvement. 8220;This was a condition that has never had any useful treatment. We have done things to help the eye reduce the pressure, but none really work to any degree,8221; said Dr Neil Miller, the team8217;s lead ophthalmologist.

THE OTHER OPTIONS

Current FDA-approved therapies include paracentesis sticking a needle into the eye and withdrawing fluid, breathing a mixture of carbon dioxide and oxygen gas, and eye massage. All are designed to restore blood flow, but none works well.

TPA is typically used to treat stroke and heart attacks, but in 1996, German researchers tried it on eye stroke victims for the first time. Hopkins researchers modified the technique to reduce the length of the procedure, the quantity of drug used and the danger of complications, which can include bleeding, damage to arteries and stroke.

WHO BENEFITS

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All of the team8217;s patients were treated within 15 hours of losing vision. The time element is critical, Aldrich says, because the eye tissue dies gradually over the next few hours. 8220;Time is retina. If you restore blood to the tissue sooner, then you have a greater chance of recovery,8221; Aldrich said.

The time factor might have saved Jablonski8217;s eyesight in April 2001. Within 10 hours of losing vision, Jablonski was receiving TPA treatment. Others in the Hopkins study weren8217;t so fortunate: Five out of 21 patients saw no improvement and remained essentially blind.

Some doctors also caution that the procedure poses its own dangers 8212; including stroke and heart attack. 8220;Not all institutions can offer this therapy. They would need very well-trained interventionalists,8221; Miller said. 8220;But the risks are decreased in experienced hands.8221;

For their part, Hopkins researchers8217; next step is controlled, randomised, multicenter trials to confirm their initial success and address the safety of the treatment. For patients, they say, the most important message from the report is recognising the warning signs of an eye stroke.

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8220;If you lose vision abruptly, you need to go to the ER right away,8221; Miller said. 8220;Do not wait until the next day to see an ophthalmologist, because then it may be too late.8221;