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A photochromic eyeglass lens, after exposure to sunlight while part of the lens remained covered by paper. Photochromism is the reversible change of color upon exposure to light. It is a transformation of a chemical species ( photoswitch ) between two forms by the absorption of electromagnetic radiation ( photoisomerization ), where the two ...
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.
The lens progressively darkens and turns yellow. [9] Blue light is absorbed by the lens, preventing blue light from reaching the retina at the back of the eye. [12] To prevent retinal damage, the lens has to lower transparency. [9] This reaction causes visual impairment and the development of cataracts, [13] [14] a cloudy region in the lens.
Adjustable focus lenses, like single-focus lenses, also reduce image-jump and spatial distortion in the field of view associated with traditional multi-focal lenses. Additionally, the ideal near-vision correction can be achieved with precision, because the variable lenses emulate the focusing action of the youthful (non-presbyopic) eye.
A lens is made of two curved surfaces, and an aspheric lens is a lens where one or both of those surfaces is not spherical. Further research and development is being conducted [ citation needed ] to determine whether the mathematical and theoretical benefits of aspheric lenses can be implemented in practice in a way that results in better ...
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