A contact lens, or simply contact or CL, is a thin lens placed directly on the surface of the eye. CLs are considered medical devices and can be worn to correct vision, or for cosmetic or therapeutic reasons.[1] In 2004, it was estimated that 125 million people (2%) use CLs worldwide, including 28 to 38 million in the United States.[2] In 2010, worldwide CL-market was estimated at $6.1 billion, while the U.S. soft lens market was estimated at $2.1 billion.[3] Multiple scientists estimated that the global market would reach $11.7 billion by 2015.[3] As of 2010, the average age of CL wearers globally was 31 years old, and two thirds of wearers were female