CHICAGO • More than 70,000 children and teens go to the emergency room each year for injuries and complications from medical devices — and contact lenses are the leading culprit, the first detailed national estimate suggests.

About one-fourth of the problems were things such as infections and eye abrasions in contact lens wearers. These are sometimes preventable and can result from wearing contact lenses too long without cleaning them.

Other common problems found by researchers at the U.S. Food and Drug Administration include puncture wounds from hypodermic needles breaking off in the skin while injecting medicine or illegal drugs; infections in young children with ear tubes; and skin tears from pelvic devices used during gynecological exams in teen girls.

Malfunction and misuse are among potential reasons; the researchers are working to determine how and why the injuries occurred. Those efforts might result in FDA device warnings, depending on what they find, said study co-author Dr. Brock Hefflin.

The most serious problems involved implanted devices such as brain shunts for children with hydrocephalus (water on the brain); chest catheters for cancer patients receiving chemotherapy at home; and insulin pumps for diabetics. Infections and overdoses are among problems associated with these devices. Only 6 percent of patients overall had to be hospitalized.

The study appears in Pediatrics, published online today.

Hefflin and lead author Dr. Cunlin Wang work in the FDA's Center for Devices and Radiological Health. They note there has been recent concern about medical device safety in children, particularly because many devices intended for adults are used in children.

Hefflin said the study was the first to evaluate device-related injuries in children only.