Low Vision Devices
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Telescopes are the only optical devices that assist a low vision person with distance tasks. Two primary types of telescopes are used: hand held or frame-mounted. If mobility and ease of use is desired, a hand held telescope provides a simple, optical tool for viewing objects outside the person’s visual capability. However, if hands-free viewing is needed, a bioptic mounted design works best. This type is typically chosen when the visually impaired person is seeking the privilege to drive a motor vehicle and needs magnification to meet state licensing standards. Both telescopes give great improvement to anyone who needs to improve distance spotting.
Illuminated Stand Magnifier
Hand-held magnifiers are the most common low vision device used by the visually impaired. Most provide good quality magnification for simple, short-term reading tasks such as reading price tags, medicine bottles and food packaging labels. However, longer-term reading often requires a more stable optical system, thus an illuminated stand magnifier is chosen. These magnifier have housings around the lens that provide proper working distance and clarity for the user. Stand magnifiers are better choices for reading mail, newspapers, magazines and books.
Full Diameter Microscopes
A microscope is a high plus powered lens used primarily for reading and is typically fitted only to the better eye. Most require a closer working distance between 5 inches to as close as 1 ½ inches from the lens. Reading material is brought close and the microscope creates a clear image from edge to edge improving the reading experience. The greatest advantage is that it allows both hands to be free to hold the reading material. Microscopes also provide a wide field of view compared to some hand-held magnifiers held much further away.
Handheld Video Magnifiers
An electronic, battery-operated magnification system used primarily for short-term near viewing tasks such as reading mail, recipes, food package labels, price tags, and restaurant menus. Utilizing the same optical systems as larger, desktop systems, the compact design provides portability and enhancement abilities many visually impaired persons need to read on-the-go.
Closed Circuit TV systems (CCTV Systems)
An electronic video magnification system providing enhancement of all print types with both contrast changes for better viewing of print to high magnification capability for easier reading of the smallest print types. These desktop units can be compatible with computer systems to provide the visually impaired user with split-screen viewing for multi-tasking needs at work, school or home. The CCTV has been shown to increase reading performance, speed and duration when compared to a traditional magnifier whose field of view is narrow. Many systems now incorporate OCR technology for text-to-speech capability.
Typically considered by dentists and surgeons as the magnification tool of choice for working in small areas, these devices can be used by visually impaired persons who need a longer working distance with good magnification for accomplishing many near focused tasks. Most reading telescopes are binocular, but can be used only with one eye if necessary. These devices are great for tasks requiring hands-free reading, typing, sewing or craft work. The biggest disadvantage is a narrow viewing field.