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2. Magnifying glass - Wikipedia

   en.wikipedia.org/wiki/Magnifying_glass

   A pen seen through a magnifying glass Jim Hutton as detective Ellery Queen, posing with a magnifying glass. A magnifying glass is a convex lens that is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle. A magnifying glass can be used to focus light, such as to concentrate the Sun's radiation to ...

3. Loupe - Wikipedia

   en.wikipedia.org/wiki/Loupe

   A pair of dental loupes featuring in-lens magnification. There is a loupe light mounted on the bridge of the loupes and side shields (not shown) on the temples to protect a dentist's eyes from splatter. Dentists, hygienists, and dental therapists typically use binocular loupe glasses since they need both hands free when performing dental ...

4. Magnification - Wikipedia

   en.wikipedia.org/wiki/Magnification

   By convention, for magnifying glasses and optical microscopes, where the size of the object is a linear dimension and the apparent size is an angle, the magnification is the ratio between the apparent (angular) size as seen in the eyepiece and the angular size of the object when placed at the conventional closest distance of distinct vision: 25 ...

5. MNREAD acuity chart - Wikipedia

   en.wikipedia.org/wiki/MNREAD_acuity_chart

   The MNREAD acuity chart or Minnesota low vision reading chart is a text based chart used to measure near visual acuity in people with normal or low vision. [1] It can also be used to measure maximum reading speed, critical print size and the reading accessibility index of a person. [2] Digital and printed types of charts are available. [3]

6. Presbyopia - Wikipedia

   en.wikipedia.org/wiki/Presbyopia

   Corrective lenses provide vision correction over a range as high as +4.0 diopters. People with presbyopia require a convex lens for reading glasses; specialized preparations of convex lenses usually require the services of an optometrist. [15] Contact lenses can also be used to correct the focusing loss that comes along with presbyopia.

7. Corrective lens - Wikipedia

   en.wikipedia.org/wiki/Corrective_lens

   Higher-quality optical-grade glass materials exist (e.g. Borosilicate crown glasses such as BK7 ( n d = 1.51680 , V d = 64.17 , D = 2.51 g/cm³ ), which is commonly used in telescopes and binoculars, and fluorite crown glasses such as the best optical quality low dispersion glass currently in production, N-FK58 made by the German company Schott ...