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History of optics. Modern ophthalmic lens making machine. Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, followed by theories on light and vision developed by ancient Greek philosophers, and the development of geometrical optics in the Greco-Roman world. The word optics is derived from the Greek term ...
Eyeglass prescription. An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient. If an eye examination indicates that corrective lenses are appropriate, the ...
History. ABDO was formed in 1986 from the merger of the Association of Dispensing Opticians and the Faculty of Dispensing Opticians, following the Health and Social Security Act of 1984. The profession of dispensing opticians has been regulated voluntarily since 1926 and, as a statutory profession, by the Opticians Act since 1958.
A Fresnel lens ( / ˈfreɪnɛl, - nəl / FRAY-nel, -nəl; / ˈfrɛnɛl, - əl / FREN-el, -əl; or / freɪˈnɛl / fray-NEL [1]) is a type of composite compact lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections.
Prism glass can be found on sidewalks, where it is known as vault lighting, in windows, partitions, and canopies, where it is known as prism tiles, and as deck prisms, which were used to light spaces below deck on sailing ships. It could be highly ornamented; Frank Lloyd Wright created over forty different designs for prism tiles.
The variation of refractive index vs. vacuum wavelength for various glasses. The wavelengths of visible light are shaded in grey. Influences of selected glass component additions on the mean dispersion of a specific base glass (n F valid for λ = 486 nm (blue), n C valid for λ = 656 nm (red))