I'll be the first to admit it: I wear my contact lenses to bed most nights. I sometimes wear them longer than I'm supposed to. And on a few occasions, I've found myself nowhere near contact lens solution and used a little bit of water instead. (Shameful, I know.)

Bad contact glass wearer? That's me! If you are one of the estimated 38 million Americans who wear contacts, it's probably you, too. But here's a reason to reconsider this behavior:

According to numbers released by the Centers for Disease Control and Prevention last week, Americans make nearly a million doctor's appointments and emergency room visits a year for eye infections, most of them due to the improper use and care of contact lenses.

"People who wear contact lenses overnight 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."

Keratitis is an infection that occurs when germs invade the cornea, the clear dome that covers the colored part of the eye. The infection can cause pain, inflammation and scarring of the cornea. It can also lead to blindness.

Medication can treat the infection — more or less easily, depending on how early it is diagnosed and what type of bacteria is causing it — so consult a doctor if you notice pain or inflammation.

Even some seemingly harmless behaviors can lead to infection — for example, not replacing the lenses' case often enough. (The CDC recommends getting a new case every three months.)

And treating infection can be expensive: The CDC estimates that the cost of a doctor's visit for keratitis is about $151, on average; each emergency room visit costs an average of $587. Overall in the United States, keratitis is responsible for $175 million in direct costs.

Here are some other ways you can make your bad contact lens habits a little better, according to the CDC:

— Wash your hands with soap and water and dry them well before touching contact lenses.

— Take contacts out before bed, showering or swimming.

— Rub and rinse contacts in disinfecting solution each time you remove them.

— Rub and rinse the case with contact lens solution, dry the case with a clean tissue and store it upside down with the caps off after each use.

— Do not top off solution in the lens case; instead, pour out the old and replace it with new.

— Carry a backup pair of glasses in case your contacts have to be taken out.