Never buy colored contact lenses from a retailer that does not ask for a prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Learn more how some retailers are selling illegal contact lenses!

About 45 million people in the US wear contact lenses — and most of them do it wrong, according to a new study by the Centers for Disease Control and Prevention. Check out what you're doing wrong here!