A dome magnifier is a half-sphere made from acrylic or plastic that is designed to lie flat on a surface to provide magnification. The viewer looks into the dome to view the magnified material, and can scoot it along the surface to follow text or images. These optical devices can be useful for people with low vision, as well as those who work in dark environments or handle documents with very fine print. Poor reading conditions can cause eyestrain, and magnifiers can protect the vision.
Various dome magnifier designs are available, including versions with hand grips that make the device easier to use. Since many people with low vision are also older adults who may have arthritis or neurological problems that make fine motor control challenging, features like grips and carrying cases can make the devices easier to use. Some also have guide lines printed across the dome magnifier to underscore lines of text, useful for people who have trouble tracking as they read.
These devices can be used for an assortment of printed materials including books, newspapers, and maps. People with normal vision may find them useful when working with materials that have fine print. Nautical charts, for example, may have details printed in very small fonts that are hard to read without magnification, especially in low light. This often may be the case at night as lights are kept low to limit glare on board a boat. A dome magnifier can be stored with charts for people who have trouble reading them with the naked eye.
Many of these devices are small enough to fit in a pocket. In addition to being used in settings where people have trouble seeing, they can also provide useful spot magnification. Printers, for instance, can use dome magnifiers to inspect print quality on projects before approving them. They are also useful for checking textiles and other products that may have a fine weave or grain, to confirm their quality and look for errors that may not be readily visible to the naked eye.
Acrylic domes are popular, as they are lightweight in nature. In addition, they can resist scratches and scuffs in the event the user drops or fumbles the dome magnifier. Glass versions are also available, and can be more costly. Production costs for glass are often higher and such devices must be handled with special care, as they are more prone to smudges and surface damage that could make them harder to use.