save on contacts

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Glass was the first material to be used for lenses lenses, and was used for several hundred years before plastic was introduced. The crown contacts 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 discolored rapidly, it did not supplant glass as the material of choice. Furthermore, save it had a relatively low index of refraction, so it wasn''t suitable on 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 exceptional optical qualities and an index of refraction of contacts up to 1.66, much higher than the conventional plastics used for lenses, and even higher than glass. Patients with high prescriptions save should ask about high index material options for their lenses. Aspheric lenses are also useful on 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 contacts 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 discolored rapidly, it did not supplant glass as the material of choice. Furthermore, save it had a relatively low index of refraction, so it wasn''t suitable on 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 exceptional optical qualities and an index of refraction of contacts up to 1.66, much higher than the conventional plastics used for lenses, and even higher than glass. Patients with high prescriptions save should ask about high index material options for their lenses. Aspheric lenses are also useful on for high prescriptions.

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