ATLANTA, Ga. (CBS) — Doctors say contact lens wearers who do not take care of their lenses are at serious risk for eye infections.

A CDC survey found 99 percent of lens wearers engage in at least one bad habit.

Doctors say contact lens wearers should not keep a lens case for longer than three months, and lens wearers should always dump the old solution instead of topping off what is already in there.

Additionally, researchers say never sleep in contacts unless prescribed by an eye doctor.

Those who do not engage in good habits raise the risk of infections, according to the survey.

According to the CDC, more than 30 million people in the United States wear contact lenses.