Low-vision adaptive aids (daily living aids or independent living aids) are devices and tools that have been adapted or invented to enable visually-impaired persons to perform sight-related tasks independently. Although prompt treatment can stop or minimize further damage to the eyes from various diseases or disorders, recovering the loss is not always possible. Therefore, one must learn to live with the damage.
Low-vision means that the eye condition cannot be corrected with eyeglasses, contact lenses, or surgery, thus lifestyles will have to be adjusted. Low-vision aids help to make this adjustment a little easier.
Often, the tool is marked with raised dots, braille, large print, or even a voice simulator. Adaptive aids may require a prescription from an ophthalmologist or low-vision specialist and may require special training for use. These aids are available through adaptive-aids catalogues. Many are constructed or adapted by the users themselves or someone they know.
The following are some of the aids available to the visually-impaired.
An abacus is used to teach mathematical skills to blind and visually-impaired students. The Cranmer abacus in an adaptive device that has a backing behind the beads to prevent accidental movement or sliding. An abacus can be used to add, subtract, multiply, and divide whole numbers and decimals. Calculations can be done faster on a talking computer or a calculator, but the Cranmer abacus is considered to be faster and easier to use than a braille Writer, Taylor slate, or pegboard. Schools for blind students offer courses in the use of the Cranmer abacus.
Health aids are instruments used by visually-impaired persons to monitor their health or administer medicine. Devices for monitoring temperature, blood pressure, pulse, and glucose levels are marked in braille or announce the measurement in a synthesized voice. Pill splitters divide pills into even halves, and guides are available for measuring liquid medications. Diabetes-related devices measure insulin to preset levels and serve as needle guides. There are also syringes available in large print.
Household aids include such cooking devices as a liquid level indicator. This device hooks over the lip of a cup and beeps or vibrates as the liquid nears the top of the cup. Other cooking devices include one-cup beverage makers, which heat liquids for soup; electromagnetic stoves, which heat food without flames or heating elements; elbow-length oven mitts; and knife slicing guides. Other aids for the home are self-threading needles, sewing machine magnifiers, magnetic padlocks (which require no combination and open with a magnetic sensor), raised large-print telephone dials, one-button automatic telephone-dialing systems, and brailled clothing tags.
Magnifiers include hand-held devices. Some include a bar magnifier, which enlarges one line of print, and hand-held aspheric magnifiers, which magnifies three to ten times the normal size. Magnifiers may lie on the page as a sheet magnifier, held by stands at a precise distance from the page or object, or attached to spectacles and swung down into place when needed. Magnifiers may also be telescopic and enable the user to see street signs or other distant objects. Electronic magnifiers or visual aids include closed-circuit television (CCTV), which employs a camera and a zoom lens to magnify a page of print sixty times normal size. Portable models are available and are constantly improving. Computer equipment enlarges texts and images. It also allows the use of word processing, spreadsheets, or just to browse the internet. A synthetic voice can be installed, but is a relatively expensive option.
Nonoptical, or environmental aids improve vision but do not use lens magnification. These factors improve the environment rather than the device or object of regard. They include illumination, light transmission, reflection control, and contrast. Illumination is improved through the use of brighter or dimmer room lighting (as needed according to the cause of the disability). Light transmission is improved through lenses, filters, and absorptive lenses, which reduce glare and highlight contrast. Reflection is controlled by visors, sideshields, specially treated lenses, and typoscopes. Contrast is enhanced by using highly contrasting colors near one another, as black ink on white paper or fluorescent strips on stair risers.
Talking, or auditory aids allow the user to access information by using the sense of hearing. They are devices that play or read the text, message, measurement, or degree according to a preset interval of time or on activation of the voice. Tape recorders are used to play and/or record communications and such recorded materials as talking books. Some models are available with stop/start foot pedals to allow for typing while listening. Many tape recorders and players contain variable speed adjustments to reduce the time spent listening.
- Speech compressors are machines that control the speed of the audio of a tape by deleting portions of the pauses between words or by shortening vowel sounds. The material is rerecorded in the shorter version, and the sound of the speech is not affected.
- Accelerated speech is text that is recorded at normal speed, but reproduced and played at an accelerated speed. Highly accelerated speech may produce a distortion in the sound of the voice, although some models contain pitch-controlling options.
- Talking books and other recorded texts are available through talking book programs or the Library of Congress. Books on cassette tape are also available through commercial publishers.
- Synthetic speech is the computerized production of sounds into words and is used in the voice output of reading machines and computers.
- The Kurzweil reading machine is a talking device that uses a computer-controlled camera to scan lines of print. A voice synthesizer “reads” the print to the user.
- Talking adaptive aids are tools that supply a voice reading of the information normally gained by sight. Such aids include the talking scale, clock, watch, timer, blood-pressure monitor, thermometer, blood-glucose monitoring kit, talking wallet (which identifies bills of $1-$10 denominations), label makers, calculators, and computer-speech output.
- Personal reading machines, or optical character recognition (OCR) system, is a type of read-aloud device that operates along the lines of a photcopier. An internal camera scans print and then reads it aloud using a synthetic voice. They can read almost anything printed, but do not work with handwritten material. It can be used on its own or connected to a computer. When linked to a computer, the scanned material can be converted into various forms including Braile, large print, voice, or computer files.
Tools and instrument aids include rulers, yardsticks, and tape measures with raised tactual readings or braille markings; saw guides with raised markings at specific degree points; drill guides and squares; calipers; and micrometers with raised-dot markings. Light probes and metal or voltage detectors locate light or flame, metal objects, or live electrical current. They sound an audible signal to alert the user. Travel aids allow the user to move in an environment safely and independently. Such aids include folding or ridged canes and electronic travel aids that are prescribed by an optometrist or ophthalmologist and include the laser cane, the pathsounder, the sonic guide, and the Mowat sensor, all of which require specialized training to use. Electronic travel aids send out light beams or ultrasound waves that come in contact with objects in the path. When the beam or waves hit an object, the device responds by vibrating or emitting a sound. They are used by approximately one per cent of all visually impaired persons. Orientation aids familiarize a visually-impaired traveler to the layout of a particular building or site. Orientation aids include tactile maps, three-dimensional maps that have raised lines and are read with the fingertips, models, three-dimensional scale representations of the site, and verbal recordings of site descriptions or travel routes.
Watches, clocks, and timer aids are available in a variety of forms. Watch covers are designed to open so the user can feel the hands in relation to the raised dots at each hour. Time-pieces may be tactually marked with dots at each hour or at set intervals on the dial. Many feature large print or bold, high-contrast numbers. Some designs announce the time audibly at the touch of a button, and others automatically announce the time at set intervals.
Writing and communication aids enable users to perform writing and reading tasks independently. Braille books, magazines, musical materials, and maps are available to those who read Braille. Large-print materials employ larger lettering for use by those with partial vision. Written materials are recorded on tape or gramophone and are available to visually impaired persons.
A script-writing guide is a template with an opening that corresponds to one line of space on a lined page. The device can be lowered one line at a time as the writer progresses down the page. Many designs allow adaptations for drawing vertical lines and for use on nonstandard-size paper. Bold-line paper is lined writing paper with heavy, dark lines in place of standard light blue lines. The bold lines are often used with a thick-tipped felt pen and may be all that is necessary to allow persons with low vision to write independently.
Templates or stencils are available in myriad forms for tasks that range from envelope addressing to cheque writing. They are made from plastic or metal and have openings or windows that correspond to the type of document. Many templates can be made to order to suit the user’s needs or documents. A signature guide is a template that has one opening to place on the signature line. A raised-line drawing kit involves a penlike stylus for forming letters or drawings on special plastic paper or mylar covering a drawing board. Drawn lines are visible and can be tactually traced. A similar device, a dot inverter, involves embossed dots that can be used to make simple maps or figures.
Thermoform is a system that uses an oven to heat plastic sheets. The heated sheets can be embossed into dots or shapes including braille letters or maps. The thermoform sheets can be used to duplicate braille pages from a master sheet.
Label markers include designs that make adhesive-backed or magnetic labels in large print, braille, raised-line letters, or “talking” labels. Three-D markers allow writing three-dimensional letters or figures that can be felt with fingertips. The ink may be brightly colored and may be used on cloth, plastic, and metal.
Braille writers or braillers are used to type braille. A slate and a stylus are portable writing devices for printing braille. The optacon is a reading device used by those who read braille. The user sweeps a line of print with a small camera held in one hand. The other hand rests on a console that receives the print and converts it to a series of vibrating pins that simulate print letters. Standard typewriters or word processors can be used for those with touch typing skills.
Computers that print braille or standard print are available with speech output. Many advances in computer access for visually impaired persons have been made in recent years. Special tools are available that convert documents into text, which can be read by a screen-reading program that synthesizes text as audible speech. In some cases, regular computers can be converted and made accessible to blind or visually impaired users.