A dome magnifier is a

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

-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 ...

. They are

plano-convex lens A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), us ...

es: 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 or vision impairment (VI or VIP) is the partial or total inability of visual perception. In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficul ...

. 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.

References

Magnifiers Magnifier, dome

See also

References