Keratitis is the biggest culprit.
Americans make nearly 1 million doctors’ appointments and emergency room visits a year for eye infections -- most of them due to the improper use and care of contact lenses, says a report from the Centers for Disease Control and Prevention.
Keratitis caused by not removing lenses before sleep seems to be the biggest culprit. "People who wear contact lenses over night are more than 20 times more likely to get Keratitis," said Jennifer Cope a medical epidemiologist at the CDC. "Wearing contacts and not taking care of them properly is the single biggest risk factor for Keratitis," which responsible for $175 million in direct medical costs each year.