A contact lens made of flexible, translucent materials. These lenses are more comfortable, can be worn longer, and are harder to displace than hard lenses, but there are disadvantages. They may not provide the same degree of visual acuity as hard lenses and they require more cleaning and disinfection. Tear production may be decreased, esp. in older patients. The soft lenses may need to be replaced every 6 to 18 months. Corneal infections can prevent further use of soft lenses, as well as causing permanent loss of vision.