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An aspheric biconvex lens. An aspheric lens or asphere (often labeled ASPH on eye pieces) is a lens whose surface profiles are not portions of a sphere or cylinder. In photography, a lens assembly that includes an aspheric element is often called an aspherical lens.
Progressive lenses are corrective lenses used in eyeglasses to correct presbyopia and other disorders of accommodation. They are characterised by a gradient of increasing lens power , added to the wearer's correction for the other refractive errors .
Glasses, also known as eyeglasses and spectacles, are vision eyewear with clear or tinted lenses mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms, known as temples or temple pieces, that rest over the ears.
Adjustable focus eyeglasses are eyeglasses with an adjustable focal length. They compensate for refractive errors (such as presbyopia) by providing variable focusing, allowing users to adjust them for desired distance or prescription, or both.
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.
A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasses or "spectacles" are worn on the face a short distance in front of the eye.
Hunter S. Thompson was known for wearing yellow-tinted driving glasses. When driving a vehicle, particularly at high speed, dazzling glare caused by a low Sun, or by lights reflecting off snow, puddles, other vehicles, or even the front of the vehicle, can be lethal. Sunglasses can protect against glare when driving.
In binoculars, ED (extra-low dispersion) glass (also sometimes referred to as a high density - HD - glass) is a high quality optical glass that increases light transmission, decreases light dispersion, and so cuts down on chromatic aberration, or "color fringing", which is due to the splitting of the light spectrum.
Glasses or "spectacles" are corrective lenses worn on the face a short distance in front of the eye. Contact lenses are worn directly on the surface of the eye. Intraocular lenses are surgically implanted most commonly after cataract removal, but recently for purely refractive purposes .
In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion.