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Monday, March 13, 2006
Antibiotic Effective Against Leading Cause of Blindness Throughout the World
A Single Dose of One Antibiotic for Treating Trichiasis is More Effective than a Six-week Regimen of Another Antibiotic.
A clinical trial funded by the National Eye Institute (NEI), part of the National Institutes of Health (NIH), has concluded that a single dose of azithromycin taken by mouth after surgery reduces by one-third the recurrence of a vision-threatening eyelid condition called trichiasis. This is in contrast to the usual six-week regimen of tetracycline ointment applied directly to the eye. This study is published in the March 2006 issue of Archives of Ophthalmology.
“This study illustrates the importance of NIH clinical trials to find treatments for diseases that affect people throughout the world,” said Elias A. Zerhouni, M.D., director of the NIH. “When we consider that an estimated 11 million people worldwide develop trichiasis every year, we see the impact that the findings of this study may have in preventing future vision loss.”
Trichiasis is a condition in which the eyelid turns inward and eyelashes rub against the eye, resulting in corneal scarring and loss of vision. It results from trachoma, an eye infection that is the leading preventable cause of blindness in the world. It is spread through contact with flies and other insects, clothing or household items that harbor the bacterium, or infected people.
Trachoma occurs in poor, overcrowded communities that have little access to clean water, waste treatment facilities, or health care. These communities are located mainly in Africa, the Middle East, Asia, Australia and some areas of Latin America.
The World Health Organization (WHO) previously endorsed a multi-faceted strategy to control trachoma, including surgery for trichiasis and application of tetracycline after surgery.
In this study, called Surgery for Trichiasis, Antibiotics to Prevent Recurrence (STAR), eye infection with the bacterium that causes trachoma was present in 19 percent of the adults with trichiasis in Wolayta Zone, Ethiopia, the location of the clinical trial. More than 77 percent of the patients were women, who have four times the rate of trichiasis than men. Women often contract trachoma repeatedly by taking care of infected children.
“This clinical trial was relatively inexpensive to conduct, and produced results that may well save the vision of millions of people,” said Paul A. Sieving, M.D., Ph.D., director of vision research at NIH. “We look forward to supporting future trials to treat blinding eye diseases worldwide.”
“The simple surgical repair of the eyelid to prevent blindness has been plagued by high rates of recurrence of trichiasis — up to 50 percent in some areas,” said study chairman Sheila K. West, Ph.D., Wilmer Eye Institute, Johns Hopkins University. “In this study, by administering a single dose of azithromycin after eyelid surgery, we were able to reduce recurrence of trichiasis by 33 percent. This finding has major implications for improving the outcome following surgery.”
Continuing, Dr. West explained, “Some of the high rate of recurrence, no doubt, is due to poor surgical technique. Surgeons should be well trained and certified to ensure optimal outcomes. Future trials will need to standardize the procedure when testing surgical therapies.”
For this trial, the researchers from Wilmer Eye Institute partnered with ORBIS International, a nonprofit organization that works to eliminate blindness in developing countries. ORBIS trained Integrated Eye Care Workers (IECWs) to perform the eyelid surgeries, and Wilmer Eye Institute certified them, following WHO guidelines to ensure quality. The surgeries performed by the IECWs were as successful as those performed by ophthalmologists, and recurrence rates overall were low.
The results of this clinical trial, Dr. West believes, are transferable to other settings because most countries with widespread trichiasis now have access to a free azithromycin distribution program.
Thomas Quinn, M.D., an investigator with the National Institute of Allergy and Infectious Diseases, another component of NIH, and Johns Hopkins University, was a collaborator and co-author on the study.
Pfizer, Inc., through the International Trachoma Initiative that it co-sponsors with the Edna McConnell Clark Foundation, provided the azithromycin used in this trial.
For more information about eye health, the causes and treatment of vision problems and much more, visit the National Eye Institute Web site at www.nei.nih.gov.
The National Eye Institute is part of the National Institutes of Health (NIH) and is the Federal government’s lead agency for vision research that leads to sight-saving treatments and plays a key role in reducing visual impairment and blindness. The NIH is an agency of the U.S. Department of Health and Human Services.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
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