Britain used for contact lenses water box of a survey, found that up to 77% of the water box with bacteria, 8% was even amoeba. The survey reflects the most users ignore the contact lens fittings cleaning and maintenance, but the irony is that parts of the importance of clean is not less than the purity of the lens itself. It's proved that if use water that is impure box, infection of bacterial keratitis (microbial keratitis) probability will be four times the size of the general. In recent years, the contact lens fitting with more attention paid to the clean, the department of health also will contact lenses water box in 2006 on the second level medical equipment. But as early as in 1997, my contact lenses in water box has already been the FDA identified as the second level medical equipment, so contact lens fitting clean is indeed we need to pay attention to issues.