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Safety glasses or spectacles, although often used as a catch-all term for all types of eye protection, specifically revers to protective equipment that closely resembles common eye wear. To meet most national standards, spectacles must include side shields to reduce the ability of debris to get behind the lenses from the side.
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 ...
This specifies the part of the prescription designed primarily to improve far vision. In a bifocal lens, this generally indicates what is to be placed in the top segment. NV is an abbreviation for near vision. This may represent a single-vision lens prescription to improve near work, or the reading portion of a bifocal lens.
Cataract surgery, also called lens replacement surgery, is the removal of the natural lens of the eye that has developed a cataract, an opaque or cloudy area. [1] The eye's natural lens is usually replaced with an artificial intraocular lens (IOL) implant.
Uncoated glasses lens (top) versus lens with anti-reflective coating. The reflection from the coated lens is tinted because the coating works better at some wavelengths than others. An antireflective , antiglare or anti-reflection ( AR ) coating is a type of optical coating applied to the surface of lenses , other optical elements, and ...
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. Contact lenses are worn directly on the surface of the eye.
Prism lenses (here unusually thick) are used for pre-operative prism adaptation. Eye care professionals use prism correction as a component of some eyeglass prescriptions.A lens which includes some amount of prism correction will displace the viewed image horizontally, vertically, or a combination of both directions.
An improvised pinhole has a similar but better effect. The same principle has also been applied as an alternative to corrective lenses: a screen of pinholes is mounted on an eyeglass frame and worn as pinhole glasses. Differential diagnosis: pinhole worsen vision: Macular diseases, [5] central lens opacities [6] Vision static with pinhole ...