acuvue 2 contact

Glass was the first acuvue and 2 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 contact 1.52.Optical-quality acrylic was introduced for lenses use in the acuvue early 1940s, but because it was easily scratched, brittle, and 2 discolored rapidly, it contact did not supplant glass as the material of choice. Furthermore, it had a relatively low acuvue index 2 of refraction, so it wasn''t suitable for people with large refractive errors. A plastic called CR-39, introduced in the 1960s, contact was more suitable. Today, lenses wearers can also choose between polycarbonate, acuvue which is the most impact-resistant material available for eyewear, and polyurethane, which has exceptional optical qualities and an index of refraction of up to 1.66, 2 much higher than the conventional plastics used for lenses, and even contact higher than glass. Patients with acuvue high prescriptions should ask about high index material options for their lenses. Aspheric lenses are also useful 2 for high prescriptions.

contact The concept of corrective lenses that sit directly on the eyeball was developed in the ninth century, but it was contact not until the late 20th century that manufacturing and grinding techniques for contact were perfected. Originally acuvue contact were made of glass, then later of hard plastic, and still later of flexible, highly oxygen-permeable 2 soft plastic. Today, the majority of lenses worn are of two basic types: rigid gas permeable (so-called "hard" lenses) and lenses. best lenses are smaller and more durable, but require a longer period of adjustment for the wearer. Hard contact can correct some vision problems, like astigmatism, that the lenses cannot. The lenses are slightly larger than best lenses. They are more comfortable and less expensive, but can be easily torn. The latest generations of contact contact are extended and disposable lenses. extended lenses are acuvue intended to be worn for several 2 weeks at a time, contact while disposable lenses are thrown away every day or every few weeks, or in the newest versions, every day.