What are silicone hydrogel contact lenses
Soft contact lenses were made possible in the 1960s and 1970s by the development of water-loving polymers: large molecules made of repeated pieces (think of a long train of many railcars). These were called "hydrophilic gels" or simply "hydrogels." Silicone hydrogel is the latest in a line of developments aimed at increasing the oxygen permeability (increased comfort, longer wear and better eye health), wet ability (better comfort) and clinical performance of contact lenses. Silicone has higher oxygen permeability, allowing more oxygen to pass, than water, so oxygen permeability is no longer tied to how much water is in each lens. There are many types of technology transfer , even generations, of silicone hydrogels used to manufacture contact lenses today. These come with technical names such as galyfilcon, senofilcon, comfilcon and enfilcon. Each contact lens, whatever the material, is U.S. FDA-approved or cleared for specific wear and replacement conditions. ...