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Transitions Optical is a U.S.-based company known for manufacturing photochromic lenses, which darken on exposure to specific types of light. The company was founded in 1990. [1] In 1991, Transitions Optical became the first company to commercialize and manufacture plastic photochromic lenses. [2]
A photochromic eyeglass lens, part of the lens darkened after exposure to sunlight while the other part remained covered. A photochromic lens is an optical lens that darkens on exposure to light of sufficiently high frequency, most commonly ultraviolet (UV) radiation. In the absence of activating light, the lenses return to their clear state.
Clear lens extraction, also known as refractive lensectomy, custom lens replacement or refractive lens exchange is a surgical procedure in which clear lens of the human eye is removed. Unlike cataract surgery , where the cloudy lens is removed to treat a cataract , clear lens extraction is done to surgically correct refractive errors such as ...
6 'Transitions' lenses. 1 comment. 7 Photosensitive glass. 1 comment. 8 External Reference changed. 1 comment. 9 Sentence needs work. 1 comment.
Typical sunglasses lenses are tinted for protection against bright light or polarized to remove glare; photochromic glasses are clear or lightly tinted in dark or indoor conditions, but turn into sunglasses when they come into contact with ultraviolet light. Most over-the-counter sunglasses do not have corrective power in the lenses; however ...
Precision glass moulding can be used to produce a large variety of optical form elements such as spheres, aspheres, free-form elements and array-structures. Concerning the curvature of the lens elements, the following statements can be drawn: Acceptable lens shapes are most bi-convex, plano-convex and mild meniscus shapes.
improved lens manufacturing and measurement technology. Today the complex surfaces of a progressive lens can be cut and polished on computer-controlled machines, allowing 'freeform surfacing', as opposed to the earlier casting process, thus explaining the difference in price.
Lenses can be easily removed and swapped for a different lens, usually of a different color. The purpose is to allow the wearer to easily change lenses when light conditions or activities change. The reasons are that the cost of a set of lenses is less than the cost of a separate pair of glasses, and carrying extra lenses is less bulky than ...
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