Assistive Technologies for the Visually Impaired Older Adult

In this chapter, assistive technology is considered as “a broad range of devices, services, strategies and practices that are conceived and applied to ameliorate the problems faced by

individuals who have disabilities.”9

PL 100-407, the Technical Assistance to the States Act, provides the definition of a device:

Any item, piece of equipment or product system, whether acquired commercially off the shelf, modified, or customized that is used to increase, maintain, or improve the functional capabilities of individuals with disabilities.

Because this definition emphasizes the functional capability of older individuals with disabilities, it is important to our discussion of nonoptical technologies. The successful use of technology in the environment and for the task for which it is intended is the ultimate goal. Functional outcomes are the only important measure of success.

PL 100-407 defines assistive technology service as, “any service that directly assists an individual with a disability in the selection, acquisition, or use of an assistive technology device.” The broad spectrum of services that are recognized by this law include (1) evaluating the need for technology; (2) acquiring the technology;

(3) selecting, designing, repairing, and fabri-

cating assistive technology systems; (4) coordinating services with other therapies; and

(5) training individuals with disabilities and persons working with them to use the technologies effectively.

Technologies may be characterized in a variety of ways that are useful in a discussion of low vision rehabilitation. With the increasing need to look at the service delivery system of low vision as integrated with other forms of physical medicine and rehabilitation in the U.S. health care system, a logical outgrowth of the definitions of technologies and services provided earlier is to characterize low vision technologies in the framework of the technologies that provide improved functional outcomes for other disabilities.

ASSISTIVE AND REHABILITATIVE OR EDUCATIONAL TECHNOLOGIES

Technologies that help an individual carry out a functional activity are termed assistive. Technology can also serve as a part of the education or rehabilitation process. This technology can be thought of as devices or programs that assist in developing skills for the use of assistive technologies. For example, a flex-armed lamp used to provide illumination for reading is an example of nonoptical assistive technology for

enhancing visual ability. Software that assists in enhancing the use of a preferred retinal locus for reading is rehabilitation technology.

LOW TO HIGH TECHNOLOGIES

Often inexpensive, simple devices that are easy to use may be designated low technology, whereas more complex, more expensive, and more difficult to use devices may be designated as high technology. According to this distinction, typoscopes, canes, and slate and stylus may be thought of as low technology, whereas computer programs, refreshable Braille, and closed-circuit televisions (CCTVs) may be thought of as high technology.

According to Vanderheiden,26 an appliance is a device that provides benefit independent of an individual’s skill level. A tool is a device that requires the development of skill in its use. The distinguishing factor between tools and appliances is the skill level of the user; the benefit a tool provides is directly related to the skill of the user. These concepts can be easily applied with low vision devices. Some devices are intuitive, and their benefit is applied immediately on use, such as lamps and sun lenses. Others cannot be used and benefit cannot be derived unless the user is skilled, such as with computers or CCTVs. The more low vision devices are characterized as tools, the more the need for the appropriate selection of devices and skill acquisition by the user becomes apparent. Some users are able to benefit immediately from a device. Persons whose visual fields are intact are often able to read immediately with spectacle magnifiers with merely a brief demonstration of the focal distance and field of view. Those with central scotoma, however, may require extensive practice and training to identify and use their preferred retinal locus accurately and to develop visual strategies for recognizing words and maintaining comprehension despite slow rates of reading. In this case, the need for practitioners’ expertise in prescription and the need for extensive training are related to the attributes of the user as much as the attributes of the tool.

MINIMAL TO MAXIMAL TECHNOLOGIES

Both persons who are visually impaired and the technology they might require can be considered along a continuum of disability. The dis-

ability related to beginning age-related macular degeneration may require only stronger bifocal or half-eye lenses, protection from glare outdoors, a flex-armed lamp for task lighting, and other minimal technology. A person who has lost vision because of diabetic retinopathy, however, may require maximal technology that includes a computer with speech or Braille output or a long cane or guide dog for safe and efficient travel. These approaches may make use of environmental adaptations such as audible traffic signals, texturized subway guides, and other tools and techniques for independence, safety, and quality of life. Minimal technologies may be those that augment rather than replace function and have been termed orthoses, or orthotic devices. The term prosthetics or prosthetic device is used to describe those devices that replace function. Although these terms were originally developed to describe braces of various types or devices that replace body parts, the terms have been broadened to include all assistive technology devices.

General Technologies

General technologies are those that are used across a wide range of applications; they are designated as positioning systems, control interfaces, and computers. Although the principles of ergonomics are not widely known or used in low vision service delivery in the United States, they are nonetheless at work in the environments of persons with low vision who are using assistive technologies. When ergonomic positioning is incorrect, persons tire faster and may blame fatigue, headache, or body pains on the low vision device instead of the uncomfortable positioning.

Commercial to Custom Technology

The continuum in this category includes products commercially available to everyone, to products commercially available to those with low vision, to customization of commercially made products, to a completely customized product. Designers and manufacturers of products that are commercially available to everyone are beginning to use the principles of universal design. These principles have led to products available to the general public that are designed to recognize that enhancing the ability to use

vision is important, especially to older persons. Computers are now designed so that universal adaptability includes increasing the print size on the screen. Any kitchen supply store carries measuring cups and spoons with large size markings.

When an older person is no longer able to achieve task function with a commercial universal design technology, then commercial technology designed for persons with low vision can be used. For example, a user with low vision can no longer read the computer screen with the built-in enlarged type. A variety of commercially available devices may assist, such as magnification software (e.g., Zoomtext, Ai Squared, Manchester Center, Vt.) and optical magnifiers.

Ways of categorizing technologies are available to older persons. A few rising tides will carry technology development in this field, including (1) the increasing numbers of older persons who will develop low vision in the coming years, especially baby-boomers; (2) the concept of universal design that will include the demands and requirements of these aging boomers; (3) the increase in miniaturization of computer components; and (4) the increase of “wearable” computer design that will allow access to information with a wide variety of interfaces. As technology is developed at a dizzying pace, many of the design obstacles that have created barriers for the development and deployment of low vision technologies in the past will be removed. Barriers related to optical concepts; the difficulties in designing, developing, and marketing to a low-incidence disability population; and the separation of low vision from other physical medicine and rehabilitation populations are being swept away. As more research is helping define the visual difficulties of normally sighted older persons, the past categorization of low vision is becoming outdated. Many more people have visual difficulties than were previously realized, and they need to understand how to access technologies that will allow them to achieve the independence and quality of life that they expect.

Visual Function

Visual impairment inhibits gaining sensory information from the environment. The clinical

visual functions and descriptions of the types of visual impairments experienced by older persons are described in other chapters. However, in relation to technologies, visual limitations can be characterized in terms of intensity (size), frequency or wavelength (color or contrast), and visual field (central or peripheral or both). Low vision technologies may enhance the visual image by increasing the size, enhancing the contrast, or displacing the visual target in the visual field. But a variety of technologies use other ways of displaying visual information.

Perceptual Function

The onset of visual impairment creates difficulties with the ability to see targets and interferes with the ability to decode visual information and make sense of what is seen. Factors of visual perception are affected by low vision and the use of assistive technology. In the process of attempting to improve the view of an object by increasing its size, visual perceptual skills may be simultaneously decreased by eliminating cues for perception such as perspective and motion parallax. Perceptual cues related to convergence and binocular disparity are eliminated when monocular devices are used The effective use of assistive technology forces the user to acquire or improve perceptual skills, such as part-to-whole relationships and visual closure, to integrate visual images that will allow effective functioning with a different view of the world.

Cognitive Function

Cognitive function is important to learning new skills. Individuals who will benefit from technologies must learn to do new things in new ways. The importance of cognitive function has been recognized by Medicare policies that require cognitive testing by some screening, usually the Folstein Mini-Mental State Examination,7 and that practitioners state how users who score lower than the cutoff will benefit from the service. Cognitive function decreases if the user does not have access to stimulation. Many normally sighted older persons are able to read, watch stimulating television, complete crossword puzzles, and engage in a variety of mentally stimulating tasks that assist them in

keeping their cognitive skills. Those techniques are denied, however, to persons with low vision who are not able to access these activities. Low vision devices, training, and daily practice enhance visual function and may also enhance cognitive function and keep the minds of older persons stimulated.

However, even persons who have diminished cognitive function can still benefit from technologies if goals for low vision rehabilitation are switched from independence to reducing caregiver burden. Some low technologies can be used despite decreased cognitive function (such as illumination controls, increased contrast in the environment). Even some high technologies can be useful for individuals with diminished cognitive function if the activity is a familiar one, such as reading materials that are well loved, familiar, and comforting that can still be enjoyed by speech output or on CCTV. Caregivers may get other tasks completed while the person with low vision and reduced cognition is occupied.

Psychosocial Functioning

Everyone who works in low vision has a story of some individual who has shown great promise of benefit with a low vision device and then did not use it because he or she did not want to be seen using it. Human beings value appearing as much as possible like peer groups and being viewed as strong and capable. Anxiety and depression are common reactions to loss, and age-related visual impairment is complicated by the other losses associated with aging. Older adults may hold many negative stereotypes associated with visual impairment: increased helplessness, inhabiting a world of darkness, increased vulnerability to crime, and the perception that devices mark them as different or to be pitied. Older adults may attempt to pass as fully sighted to avoid having others project these negative stereotypes onto them. But attempting to pass as fully sighted may cause other difficulties. For example, older adults with low vision do not recognize faces well, and the lack of a friendly hello when passing acquaintances may be interpreted as unfriendliness. Failure to use alternative techniques for identifying targets and moving in the environment may lead to falls, burns,

incorrect medication dosages, or other safety hazards.

In a study of low vision device use among veterans, most of whom were older men with macular degeneration, family support was the most powerful predictor of continued use of devices up to 2 years after their prescription. Providing information and support to family members who are experiencing the impact of an older relative’s vision loss can be powerful. The entire family experiences visual impairment and the caregiving system, not just the older person, and both social and psychological concerns must be addressed. The loss of vision by one family member can disrupt roles in the family, create economic demands, and add stress when tasks previously performed by the older adult must be performed by someone else.

Assisting older adults with low vision in continuing social activities, such as hobbies, crafts, games, and traveling, can help them maintain important contacts with family and peers. Social support and contact were associated with less depression in older adults with low vision.16 Support groups can assist older adults with low vision in completing and implementing their rehabilitation as well as facilitating adaptation to vision loss.27 Peer support or mutual aid groups that meet regularly to share concerns may be especially beneficial for older adults. Facilitating assertiveness for older adults is recommended because it is linked to less depression and more social support.16 Social skills training in assertiveness for older adults with low vision has been shown to be effective in decreasing depression and deriving greater satisfaction in life.15

Motor Control

Manipulating low vision devices is difficult for some older users because of problems with motor control. Hand tremors and arthritis may weaken hands and cause pain. Prospective closed-caption television users may have difficulty manipulating an x-y platform. Low vision devices may cause difficulties with balance and increase the likelihood of falls. According to one study eye position in space was an active, integrated component of standing.10 Both the oculomotor system and the head motor system in older persons are coordinated to direct gaze

and, when necessary, work to suppress the vestibulo-ocular reflex. A breakdown in the gaze control mechanisms in older persons could contribute to the risk of falling and fallrelated injuries.

Ergonomic Positioning

Principles of ergonomics applied to workstations have shown that increased comfort and decreased energy expenditure can increase the work output of persons in a variety of situations.19 Ergonomics can be defined as “(1) the science of fitting the workplace to the worker, or (2) a biomechanical approach to workplace design.”1 Physiological changes that accompany the aging process include sarcopenia, reduced bone mineral density, reduced maximum oxygen uptake, and reduced muscular strength. Morbidities related to these physiological changes include musculoskeletal instability, osteoporosis, reduced endurance, and a reduction in overall functional ability.14 If an ergonomically incorrect environment further stresses persons with these known age-related physiological changes, many may experience elevated levels of discomfort.

In a study of ergonomic positioning for older persons who read with devices, reading rate was significantly improved by ergonomic positioning of older readers with low vision, and discomfort while reading was significantly reduced.28 The study demonstrated that readers who are using low vision devices can benefit from short-term and inexpensive ergonomic interventions that significantly improve reading and may increase the amount of time the reader can spend reading comfortably. Solutions presented by various sources were easily adapted for workstations by readers with low vision in this project.6,13,20

NONOPTICAL DEVICES

Devices for Ergonomic Positioning

The clinician should first consider the patient’s reading or work environment. The desk or work area should be at an appropriate height for the specific task to be performed. The selection of the chair should be taken seriously. The ABC’s of chair selection should be followed (armrests, backrests, chair height, and seat). To help the patient select the best chair, a tool such

Fig. 15-1 Reading stands.

as the Ergonomics Seating Evaluation Form (http://ergo.human.cornell.edu/ahSEATING.html) can be used to evaluate the quality of different chairs.

Once the basic ergonomic platform is specified, other tools can be used to position the reading or work material appropriately. In general, the postural and positioning demands are best met with reading stands, easels, copy stands, lapboards, clamps, computer monitor stands, and adjustable tables. Posture and positioning devices are especially important to older adults with arthritis, Parkinson’s disease, or other infirmities that affect the ability to hold and manipulate objects.

Tinker25 showed that reading is improved when the reading material is positioned at a right angle to the patient’s line of sight and set 45 degrees down from the vertical. For most applications, simple bookstands or easels provide the best solution to this ergonomic problem. These may include the Eschenbach slanted reading stand and Able Table and Wooden Reading Stand (Able Table Co., Weir Enterprises, Santa Cruz, Calif.) (Fig. 15-1). For reading material on sheets of paper, an inexpensive clamp-on copyholder usually works well. If the reading material is heavy or if it needs to be positioned closer to the patient the Shafer Reading Stand (American Printing House for the Blind, Louisville, Ky.) can be used. When a patient reads in bed, the Posture Rite Lap Desk (Hoyle Products Inc, Glennville, Calif.) has a nonglare, hard surface attached to a fabric cushion (see Fig. 15-1). For computer work, a monitor stand

can be used to position the monitor at the best reading distance.

Relative Size Devices

Print

The most commonly used adaptive devices are those that use relative size magnification. These super-sized aids include large print, telephone dials, watches, thermometers, clocks, checks, crossword puzzles, thermostats, calendars, sheet music, and games.

The amount of relative size magnification is the ratio of the size of the original object to that of the enlarged object. For example, if the size of standard print is 1 M and 2.5 M print is used instead, the magnification is 2.5×.*

Other factors leading to improved readability must be considered when using large print. These include print darkness, paper weight and color, letter and line spacing, margin size, and font. In general large print should have clean edges and be of such a size that the lower case o is approximately 2.7 mm in height. The paper should be lightweight and have good opacity and high contrast. Line length should be no less than 6 inches, and hyphenation should be kept to a minimum. Finally, periods and commas should be larger than normal.2

Large print has both advantages and disadvantages. The advantages include simplicity, ease of use, and acceptance by most people. Large print may also be used in conjunction with low power optical devices as a training tool. Once the individual learns how to use the low power magnifier with the large print, he or she can then more easily progress to higher powered magnifiers with standard-size print.

The primary disadvantage of large print includes the limited amount of magnification, production costs, and limited availability. Few large-print books exceed 18-point type and therefore have only 1.8× magnification. This

low magnification is of little benefit for individuals with visual acuity of 20/400 or less. Production costs soar as print size increases. The number of larger print pages required is governed by the square of the amount of magnification needed. For example, if the size of the print is doubled, four times the number of pages are needed. Other costs such as storage and shipping also increase as print size is enlarged. Although the availability of largeprint documents and books has improved over the years, obtaining the latest best seller or most textbooks in large-print versions is still difficult. Several resources for large-print products are available. These include the American Printing House for the Blind and the National Library Service for the Blind and Physically Handicapped. Easily obtainable large-print periodicals and newspapers include Reader’s Digest and the New York Times. Large-print editions of dictionaries, bibles, and cookbooks can be found in most bookstores.

Other Devices

Many devices used to accomplish various activities of daily living also come in supersized formats. The ability to manage finances is an important activity of daily living. Writing checks and balancing a checkbook are key to retaining independence. In addition to check writing guides that can be used with standardsize checks, large-print checks and check registers are available (Fig. 15-2). A large-print check register available from LS&S (Northbrook, Ill.) uses a spiral binding, which allows the register to lay flat. It has seven entries per page and a

Fig. 15-3 Large-print watches, phone dial, playing cards, and thermostat.

total of 26 pages. Deluxe Check Printers (Shoreview, Minn.) has a large print check, the Guide-Line, that is available from most banks and comes with a large-print check registry. For older individuals with access to the Internet, online banking and bill paying may make using paper checks obsolete.

Large-print rotary phone dials and largeprint push-button overlays or phones can be purchased. Keep in mind that most large-print phones only provide large numbers. The letters are either missing or are still relatively small (Fig. 15-3). For severely vision impaired persons, voice-activated dialing or operator-assisted dialing may provide a better solution.

The ability to tell time is also a necessary activity of daily living. Large-face clocks and watches are obtainable from several distributors. Typically the clock or watch has a white face with large black hands and numbers (see Fig. 15-3). Some large-print watches use lightemitting diodes (LEDs) or liquid crystal displays (LCDs).

All people need to play. Fortunately, many games may be obtained in large-print editions. Various companies have everything from largeprint bingo to jumbo-faced playing cards (see Fig. 15-3). Other large-print games include Scrabble, checkers, chess, and Uno. For those who enjoy crafts, spread-eye needles, largeprint embroidery designs, large-print tape measures, and other sewing and knitting aids are available.

Devices for Illumination and Contrast Control

Illumination

Without light vision is impossible, and without contrast discrimination is impossible. Most eye and vision disorders affect the ability to use available light or reduce the ability to discriminate objects in the environment; consequently, magnification alone is not always enough to improve vision function. Increasing contrast and reducing spatial frequency are typically both used in low vision rehabilitation.

In general, vision performance improves as light increases. So how much light is enough? For normal subjects, performance improves logarithmically, rising rapidly from a low level of illumination until an asymptote is reached.3,23

Eye diseases that tend to reduce retinal illumination without light scatter benefit from increased illumination. Individuals who have ocular disorders that both reduce illumination and scatter light may not benefit from more light. As a matter of fact, increased light may actually reduce vision and vision function. This phenomenon is seen when doing a glare test on an individual with cataracts. Acuity under dim room light is typically better than when the room lights are turned on. On the whole, individuals with macular disease do better with increased illumination, whereas those with cataract may do worse. Individuals with glaucoma do approximately the same as normals (more light equals better performance).11,18,24 Other eye diseases associated with glare and photophobia include aniridia, achromatopsia, albinism, clinically significant diabetic maculopathy, retinitis pigmentosa, and various cone dystrophies. Many treatments for ocular disease can also affect the need for illumination. For example, laser photocoagulation may increase glare and reduce the ability to adapt to changing levels of illumination, whereas the use of miotics to treat glaucoma, which also constricts pupil size, results in the need for increased illumination.

Higher levels of illumination can result in glare, which in turn can reduce visual performance or even result in visual discomfort. When glare causes discomfort or pain (photophobia) it is called discomfort glare. When it interferes with vision performance, it is referred

to as disability glare. There are several ways to control glare. The type, size, brightness, and position of the source can be changed, the contrast between the light source and the surroundings can be changed, or filters that change the quality or quantity of light entering the eye can be used.

The eye care professional can help the patient select the appropriate light for a given task. Fortunately, numerous types of lights (fluorescent, incandescent, neodymium, halogen) are commercially available. The least expensive but most difficult to control is natural sunlight. Although many people with vision impairment prefer sunlight, it can produce discomfort and reduce the individual’s ability to adapt quickly to changing light conditions. Sunlight is most often controlled by the use of light filters, visors, and clip-on side shields or by using hats with brims.

Many older persons do not function well with fluorescent light. Standard fluorescent illumination is harsh; provides little contrast; and accentuates blues, greens, and yellows. Because it contains a higher percentage of ultraviolet light, it can make the eye’s lens fluoresce, resulting in glare or haze. Newer fluorescent lights are now available with a range of color temperatures that mimic incandescent light. Because fluorescent lights “burn” cooler than most other types of lights, they may be useful in situations in which the person must be close to the light source.

Incandescent illumination puts out light of longer wavelengths and is considered a “warm” light, appearing more yellow than blue. An incandescent light source tends to be pinpoint and directional and produces more contrast and shadows than fluorescent fixtures. Incandescent lights require the use of diffusers and shades to reduce glare. Because the longer wavelength of incandescent light is not scattered as much as the longer wavelength of fluorescent lights, it is usually preferred by individuals with cataracts, corneal edema, or other media opacities that tend to scatter light. Many older persons prefer small, movable, adjustable incandescent light sources when reading or performing other tasks.

The Chromalux (Lighting Manufacturers & Distributors, Inc., Barrington, Ill.) bulb (neodymium light source) produces illumina-

Fig. 15-4 Typoscopes, yellow acetate filter, and writing guides.

tion that is similar to sunlight. Available in 60and 100-W frosted bulbs, use of a neodymium light source may increase short-term task performance.8

Halogen light, although bright, produces a great deal of heat and ultraviolet rays. Although some low vision devices incorporate halogen lights with a rheostat, the typical halogen light fixture is not useful for most people with vision impairment.

Light position is important to control glare and intensity. The ideal light source should be movable, be adjustable, and have a rheostat to control output. It should be placed on the side of the better-seeing eye and positioned to avoid glare. If the light does not contain a rheostat, moving the light closer to or further from the material being viewed can control intensity. Keep in mind the intensity varies by the square of the distance from the source—moving the light twice as close makes the illumination four times as bright.

The typoscope, invented by Charles Prentice in 1897, effectively reduces stray light and glare from surrounding text and acts as a line guide when reading (Fig. 15-4).22 When the typoscope is combined with a yellow acetate filter, contrast also increases.4

Pinhole glasses, stenopaic slits, and controlledpupil contact lenses have also been used as a diagnostic tool to determine if glare and photophobia are contributing factors to the patient’s complaint.

Fig. 15-5 NoIR and corning light filters.

Light Filters

Clinicians prescribe light filters to reduce glare and photophobia, improve residual visual function, reduce adaptation time, and improve orientation and mobility. Unfortunately, little objective evidence supports clinically significant improvement in visual performance with light filter use.12 A literature review by Eperjesi et al12 regarding the impact of light filters on visual acuity, contrast sensitivity, and visual field did provide some insight into what type of light filter may be best for a specific ocular condition. So why are light filters prescribed? For many individuals, tints do seem to improve vision function and occasionally even improve the level of vision impairment (better acuity or improved contrast sensitivity).

Available Filters

NoIR Medical Technologies (South Lyon, Mich.) manufactures two types of light filters: the NoIR and UVShield. According to the company, the UVShield provides visible light and 100% ultraviolet light protection and the NoIR blocks near infrared and 100% ultraviolet and offers visible light protection. Currently NoIR offers more than 25 UVShield and 18 NoIR filters. These polycarbonate filters retain their shape and have several different form factors, including large and standard fit-overs, clip-ons, and standard sunglass styles. Fit-overs also

Fig. 15-6 CCTV.

have polycarbonate side shields that are the same color as the front; consequently, they are ideal for blocking stray light that comes in from the side or above most standard light filters (Fig. 15-5). Children and infant versions are also available (http://www.noir-medical.com/). (See Chapter 11 for information on available glass photochromic lenses.)

ELECTRONIC MAGNIFICATION

Closed-Circuit Television

The CCTV is an effective low vision rehabilitation device that provides electronic magnification and, in some cases, image enhancement to allow vision-impaired persons to perform such tasks as reading and writing. The basic CCTV consists of a monitor; camera; various controls for magnification, contrast, and polarity; and an x-y table (a reading platform that moves vertically and horizontally so the material can be viewed) (Fig. 15-6). This device typically provides up to 60× magnification and allows the user to control image size, brightness, contrast, and image polarity (black letters on a white background can be reversed to white letters on a black background). Individuals can also view the monitor binocularly, write and read at a comfortable distance and change viewing distance and magnification to maximize the linear

in low vision accessibility options. In Windows XP, go to Start → Accessories → Accessibility → Magnifier. The Windows XP built-in magnifier is a screen enlarger that enlarges a portion of the display, making the screen easier to read. The Windows XP accessibility option can enlarge the screen up to nine times and can also increase contrast. The Apple Macintosh operating system includes a program called CloseView. The built-in program is also a screen enlarger. It magnifies all screen images (text, graphics, menu bar, and the mouse cursor) up to 16 times. Additionally, CloseView can inverse the Macintosh display (so that text appears white on a black background instead of vice versa; see http://www.apple.com/disability/vision/easyaccess. html). Although the Windows magnifier and CloseView are not intended as replacements for a full-featured screen-enlargement utility, they may be all that is required for individuals with mild or moderate vision loss.

A larger monitor may help other computer users. For example, increasing the monitor size from 15 inches to 22 inches increases the magnification by almost 1.5 times. Other choices include using a monitor stand or arm so the user can move the monitor closer to take advantage of relative distance magnification. If the individual moves the monitor from a working distance of 40 cm to 10 cm, magnification is increased by a factor of four. Other inexpensive options include snap-on screen magnifiers and screen polarizers. For older computer users with poor typing skills, the computer’s keyboard characters can be enlarged by using key tops with large-print characters or by using press-on large-print characters.21

Although this chapter primarily describes nonoptical devices that assist vision-impaired older adults, remember that in some instances telemicroscopes may also be used to read the computer screen. One device that allows the individual to look at the computer monitor and keyboard, across the room, and at reference material all without having to manually re-focus is the Ocutech (Chapel Hill, N.C.) autofocus telescope (Fig. 15-10).

Older individuals with visual acuity of 20/200 or less may also benefit from the use of stand-alone large-print computer programs. The number of large-print access computer programs continues to increase every year. A

Fig. 15-10 Eschenbach near telescope, designs for vision near telescope, and the Ocutech autofocus telescope.

Fig. 15-11 ZoomText computer screen magnifier.

review of all these programs is beyond the scope of this chapter, but a few well-established programs that provide most of the functionality vision-impaired computer users need are described.

Two of the most commonly used programs for Windows include ZoomText and MAGic (Freedom Scientific Inc., St. Petersburg, Fla.; Fig. 15-11). Both programs come in several versions and offer up to 16× magnification, mouse pointer enhancements, flexible color contrast and, depending on the version, speech output. (See http://www.aisquared.com and http://www. freedomscientific.com.) Free trial versions of the software are available before purchase.

Nonvisual computer access is required when screen-magnifying software fails to meet the needs of the vision-impaired person. Fortunately numerous options are available. For Windows, two of the most used programs include Window-EYES (GW Micro, Fort Wayne, Ind.) and JAWS (Freedom Scientific). Braille access solutions also exist. Obviously, when a profoundly visually impaired person is evaluated, working with the state Agency for the Blind or other local or regional aging resources is important. These rehabilitation agencies may have assistive technology specialists to determine the most appropriate nonvisual computer access technology for the person.

HEARING AIDS AND ASSISTIVE LISTENING DEVICES

Among adults aged 70 years or older, 18.1% report vision impairment, 33.2% note a hearing loss, and 8.6% have both a vision and a hearing loss.5 Several kinds of hearing aids are available. The primary types include behind the ear (BTE), in the canal (ITC), and completely in the canal (CIC) (Fig. 15-12). A BTE hearing aid fits behind the ear and has a small ear hook that extends over the top of the auricle into the ear canal. The ITC is small enough to fit into the ear canal and looks like a large ear plug. The CIC is the smallest device and is almost completely inserted into the canal, thereby making it nearly invisible (see Fig. 15-12).

Assistive listening devices (ALDs) are typically much larger than hearing aids and usually consist of a headphone and microphone (Fig. 15-13). Use of an ALD can be advantageous, especially when background noise exists. Unlike most traditional hearing aids that amplify all

B

A

C

Fig. 15-12 BTE (A), ITC (B), and CIC (C) hearing aids.

Fig. 15-13 External assistive listening device.

Fig. 15-14 Telecommunication device for the deaf.

sounds equally, ALDs amplify the primary signal, not the competing noise. ALDs that use an FM sound system are found at movie theaters, concert halls, and churches. Infrared sound systems are available for home TVs and various telephone amplifiers, and telecommunication devices for the deaf are also available to help the hearing-impaired older person (Fig. 15-14). (See Chapter 9 for a more complete discussion of age-related auditory impairment.)

Helen Keller, who was both blind and deaf, noted that she would prefer to have her hearing back instead of her vision because she believed that although blind people were cut off from things, deafness cut her off from people.19 Therefore the optometrist and the ophthalmologist should consider the need for hearing aids or assistive listening devices when working with older persons.

The performance of activities of daily living is improved with the use of assistive devices.

Unfortunately, many eye care practitioners tend to underestimate the usefulness of these aids. Additionally, most vision-impaired patients are unaware of the multitude of available assistive devices; consequently, the eye care practitioner should provide information and make recommendations to help patients select the best devices for a given task.

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SUGGESTED READINGS

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National Institute for Occupational Safety and Health: Musculoskeletal disorders and workplace factors: a critical review of epidemiological evidence for work-related musculoskeletal disorders of the neck, upper extremity and low back, Cincinnati, 1997, NIOSH.

North Carolina State University: Principles of universal design, Raleigh, NC, 2001, The Center for Universal Design.

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