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.
Under Aldrich'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 patient'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 percent of the TPA group improved their vision by at least one line on the Snellen chart - the eye chart with the big "E" at the top. Only 33 percent in the standard therapies group showed that much improvement.
In addition, a third of volunteers in the TPA group experienced an improvement of three lines or better, compared with 5 percent of patients in the standard group.
"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," said Dr. Neil Miller, the team's lead ophthalmologist. "Most patients end up blind or nearly so."
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.
All of the team'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.
"Time is retina. If you restore blood to the tissue sooner, then you have a greater chance of recovery," Aldrich said.
