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A dome magnifier is a dome-shaped magnifying device made of glass or acrylic plastic, used to enlarge words on a page or
A dome magnifier is a dome-shaped magnifying device made of glass or acrylic plastic, used to enlarge words on a page or computer screen
A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.
The di ...
. They are plano-convex lenses: the flat (planar) surface is placed on the object to be magnified, and the convex (dome) surface provides the enlargement. They usually provide between 1.8× and 6× magnification.{{cite book, title=Assistive Devices for Reading Issue 93, Part 2 of Reference circular, date=1993, publisher=National Library Service for the Blind and Physically Handicapped, The Library of Congress Dome magnifiers are often used by the visually impaired
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment†...
. They are good for reading maps or basic text and their inherent 180° design naturally amplifies illumination from ambient side-light. They are suitable for people with tremors or impaired motor skills, because they are held in contact with the page during use.
See also
*Reading stone
A reading stone is an approximately hemispherical lens that can be placed on top of text to magnify the letters so that people with presbyopia can read it more easily. Reading stones were among the earliest common uses of lenses.
The invention o ...
References