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soft contact lenses, soft contacts, soft contact lens, soft contact lens removal, soft lens 66 toric, softlens 66 toric, softperm, softperm contact, softperm contact lens, softperm contact lenses, softperm contacts, rigid and soft contact lens, rigid and soft contact lenses, special contact lenses, special effect contact, special effect contact lens, special effect contact lenses, special effect contacts, special effects contact, special effects contact lens, special effects contact lenses, soft lens, soft contacts removal, soft lens 66, softlens 66, solid blue, solid blue contact lens, solid blue contact lenses, solid blue contacts, sparkles collection, sparkles collections, sparkles contact lens, sparkles contact lenses, sparkles contacts, special contact lens, special contacts Glass was the first material to be used for lenses lenses, and was used for several hundred years before plastic was introduced. The crown glass used for lenses lenses has an index of refraction of 1.52.Optical-quality acrylic was introduced for lenses use in the early 1940s, but because it was easily scratched, brittle, and softcontactlens discolored rapidly, it did not supplant glass as the material of choice. Furthermore, it had a relatively softcontactlens low index of refraction, so it wasn''t suitable for people with large refractive errors. A plastic called CR-39, introduced in the 1960s, was more suitable. Today, lenses wearers can also choose between polycarbonate, which is the most impact-resistant material available for eyewear, and polyurethane, which has softcontactlens exceptional optical qualities and an index of refraction of up to 1.66, much higher than the conventional plastics used for lenses, and even higher than glass. Patients with high prescriptions should ask about high index material options for their lenses. Aspheric lenses are also useful for high prescriptions. Glass was the first material to be used for lenses lenses, and was used for several hundred years before plastic was introduced. The crown glass used for lenses lenses has an index of refraction of 1.52.Optical-quality acrylic was introduced for lenses use in the early 1940s, but because it was easily scratched, brittle, and softcontactlens discolored rapidly, it did not supplant glass as the material of choice. Furthermore, it had a relatively softcontactlens low index of refraction, so it wasn''t suitable for people with large refractive errors. A plastic called CR-39, introduced in the 1960s, was more suitable. Today, lenses wearers can also choose between polycarbonate, which is the most impact-resistant material available for eyewear, and polyurethane, which has softcontactlens exceptional optical qualities and an index of refraction of up to 1.66, much higher than the conventional plastics used for lenses, and even higher than glass. Patients with high prescriptions should ask about high index material options for their lenses. Aspheric lenses are also useful for high prescriptions. ©2003 www.extended-wear-contact.com. All rights reserved. |