silicone contact lenses

silicone contact lenses       Contact lens is a kind of imitation in the cornea, can with eye rotation and rotation, is not easy for people to perceive the glasses, it is also called invisible glasses or contact lenses, can be divided into two kinds of hard lens. Because it is a complete optical system and the eye, thus greatly improve the ability of vision correction, its use is: 1.High myopia glasses incurable. High hypermetropia and eyelid refractive rate difference between the available contact lenses for vision correction;   2 in addition, cataract, corneal bullous keratopathy, burns and other eye disease patients, it can maintain and improve eyesight;   3 because the occupation relationship cannot use the ordinary glasses to provide convenient, such as actors, athletes and in high temperature and high humidity environment staff;   4 can be rather than use the ordinary glasses for grooming choice.   Because of this, application of contact lenses in Europe and the United States, Japan and other countries have been quite common. For the United States, the current national wearing contact lenses to about 14000000 people, is expected by 2000, there will be 45000-9000 million people use contact lenses. Contact lens materials ideal shall meet the following requirements: 1, excellent optical properties, in the 400-750nm in the range of visible light transmittance should be greater than 90%. The refractive index and cornea is similar, in the range of 1.37-1.49;   2, good oxygen permeability, with a total of corneal metabolism needs;   3, physiological inert, no adverse effects on any side effects or potential ocular tissues;   4, certain mechanical strength, capability of eyelid blink when the pressure and scissors without deformation.      At present, used as a contact lens material with polymethyl methacrylate ( PM-MA, hard lens material ), cellulose acetate butyrate ( CAB, hard lens material ), 2-hydroxyethyl methacrylate ( HEMA, hydrogel lens materials ), methyl methacrylate ( MMA ) and poly siloxane copolymer ( hard lens material, trade name Polvcon ) and the silicone hard lens and soft lens material etc.. The contact lens materials, the silicone contact lenses with its excellent oxygen permeability, light transmittance and physiological inert, make it become the bright younger generation of contact lens material. At present red Wacker Silicones Corp has developed all silicone soft lens first commercial world ( trade name Silcoli ) and silicone soft lens first commercial ( trade name Silsoco ). The two lens 1981 for the average American food and Drug Administration ( FDA ) approved the sale of used, where Silsoco silicone soft lens is the company's ten years of research, the United States of America " magazine in 1982 Industrial Research " industrial research product award. Compared with the other contact lenses, characteristics of Silsoco silicone soft lens is almost entirely through the oxygen, the oxygen permeation capacity is more than 8 times the most sophisticated of hydrogel lenses. The oxygen permeability of corneal health, wearer feel comfortable and can prolong the wearing time. General hard contact lens for oxygen permeation ability is poor, easily cause corneal swelling and itching, therefore in short period, but some hard lenses such as PMMA hard contact lens, also must wear during the day, before going to bed to remove. The silicone contact lenses can be used for a month without wearing out continuously, the continuous wearing period is two times the current commercially available decorative contact lenses. Other features of Silsoco silicone soft lens is more stable, transparent, durability and easy processing than hydrogel lenses with tweezers, twist, tensile and bending will not tear or rupture. This new product to light the rate can be adjusted between +7.00-32.00, it almost can be used with all the myopia and hyperopia and excision of cataract.