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Nature of the Problem The aging of the human eye involves a series of changes in vi- sual performance that can be detected readily in the healthy adult. After age 40, visual acuity, range of focus, and color discrimination decrease and sensitivity to glare increases. These changes can lead cumulatively to significant visual deterioration in older people. Viewed in the context of employment, reduced visual func- tion does not necessarily have any effect on job performance but for some indivicluals, it will. This may be due to the fact that their work environment is not appropriately designed for visu- ally demanding tasks, because they have other health problems that exacerbate the effects of declining visual function, or be- cause their vision problems remain uncorrected. The negative consequences of age-related vision changes may include lower pro- ductivity, increased frequency of accidents, greater absenteeism, and ultimately the decision to leave the work force. It is of course in an employer's interest to be sensitive to the vision needs of older workers indeed, of all workers. A firm may save considerable time and money in building and sustaining a productive work force through health care and employment policies that give vision a prominent role. And since an increasing proportion of the population will be over 40 in coming years, the growing number of older workers may require the development of strategies to make their labor force participation more productive. Many firms already sponsor vision screening programs, typi- cally as part of preplacement and periodic physical examinations. Screening procedures are often limited to visual acuity testing, although other facets of vision may be tested given the physical 1
2 requirements of a job and safety considerations. For jobs in some companies, for example, color vision may be tested because nor- mal color vision is important for sorting complicated, color-coded electrical wiring. For jobs in other companies, in which depth perception is crucial for the safe handling of dangerous material, stereopsis one aspect of depth perception may be monitored so that workers wall not present a danger to thernseIves or their coworkers. Screening tests are used to determine whether an individuaT's vision is adequate for a certain job, or whether certain restrictions should be placed by the employer on a worker's performance of a job. For example, if a worker has experienced the loss of certain parts of the visual field through disease, the employer may wish to reassign the worker to a task that involves less detailed work. Alternatively, the employer may simply decide to keep the worker at the job but change the lighting conditions surrounding the task. For vision screening procedures to be effective for these various purposes, it is vital that the screening tests match the requirements of the task. On average, the visual functions of older workers differ signif- icantly from those of younger workers. These visual functions can and should be identified and tested. Many of the vision screening tests used today are inadequate to test the full visual capabilities of older workers. The tests frequently have no relevance to the work to be performed a problem that affects all workers. The screening procedures, furthermore, are not likely to include tests designed to detect the visual changes of older workerschanges that could impair job performance. And perhaps what is worse, older workers may be employed in job settings in which no thought has been given to vision screening or to their vision needs. About 25 million Americans are 65 and older; that figure will double in the next 25 years. And in the next 15 years, the baby boom wiD continue to increase the number of middle-aged workers. The demographic changes occurring in the U.S. labor force suggest that many employers should become more interested in the role of vision screening, job placement, and environmental design for sustaining the productivity and employability of work- ers. Several things are necessary, though, before employers who are interested in doing so will have the means to introduce or improve programs that take into account age-related changes in vision. First, more information is needed from scientists on the
3 implications of age-related changes in vision for the performance of specific tasks whether in manufacturing industries, informa- tion services, or other employment sectors. While vision research has generated a great deal of information about age-related visual changes in contrast sensitivity, color vision, and acuity, the connec- tion between those vision changes and job performance needs to be more clearly demonstrated. Furthermore, much of this knowledge about vision changes with age is based on studies of individuals under the age of 65. Second, more information is needed about the vision screening programs already in place in businesses throughout the nation. It is important to establish whether the vision tests currently being administered are appropriate for detecting the visual changes that normally occur with age and whether they are job relevant. It is also important to determine if other vision tests are available or could be developed for use with older workers. Third, more information ~ needed about job placement programs based on the visual capabilities of workers. Some companies have introduced job coding systems that include specification of vision skills. We need to assess the extent to which this approach has application for older workers and in settings other than the ones in which job coding is currently being used. Finally, it is important to develop and disseminate information on how work stations and the work environment could be made more responsive to the vision needs of older workers. Although there is much information currently available on environmental design, only a portion of it addresses the vision needs of older workers. Much more could be done ir1 this area. It should be made clear at the outset that the terms older worker or aging worker do not correspond to a particular worker or a particular age group. Visual processes age at different rates and present problems for people at different stages of their lives. Loss of focusing power (presbyopia), for example, typically manifests itself in people in their forties, but the ability to resolve moving targets (dynamic acuity) may not deteriorate for most people until they are well into their seventies. Moreover, for any single visual function, such as dynamic acuity, there are substantial differences among individuals of the same chronological age. We should also make clear that there is no "typically older worker. There are huge differences between individuals with respect to any one of the vision problems that are the subject of this report.
4 VISION CHANGES AND OLDER WORKERS Although there is a so able literature on aging and vision, little of this research has addressed the special problems of vision in the work setting. A useful first step would be the identification of those changes in vision with age relevant to an individual's ability to work, some of which are detailed below. Smaller Pupil Size and [oss of Focusing Ability While there are many normal changes of significance in the nondiseased aging eye, the most functionally important changes seem to be the reduction in pupil size and the loss of accommoda- tive or focusing ability. The area of the pupil governs the amount of light that can reach the retina. Because of smaller pupil size, older eyes receive much less light at the retina. At the conference, Ian Bailey reported that the light-adapted eye of a 20-year-old receives six tones more light than that of an 8~year-old. In dark- adapted conditions, the 2~year-old eye receives about 16 times more light. In comparison to younger persons, it is as though older persons were wearing medium-density sunglasses in bright light and extremely dark glasses in very dun light. Thus, for any detailed visually guided tasks on which performance varies with illumination, older workers require extra lighting. Presbyopia is the most common visual disorder in later life. This lack of accommodative ability limits the range of usable work- ing distances. Substituting an inflexible spectacle lens for a flexible ciliary lens places the older person at a distinct disadvantage. The range of clear vision is restricted, particularly for intermediate distances. Many machines and tasks (computers, music stands, library shelves, etc.) are not designed for comfortable bifocal viewing, requiring fatiguing and inefficient postural contortions. Nor do trifocals and variable focal lenses always solve the prow lem if they restrict the visual field and create new aberrations or awkward head and eye positions. When the task involves moving, climbing, or otherwise navigating under conditions of precarious stability, the presbyope may be a hazard to himself or herself as well as to others. Color vision and contrast sensitivity are also known to be affected by aging. Color vision changes cause some reduction of the ability to discriminate blues and blue-greens. The normal
5 yellowing of the lens of the eye is believed to be chiefly responsible for this effect. The aging lens and cornea often cause glare by light scatter- ing, especially for shorter wavelengths. Stray light and lenticular fluorescence washes out contrast. It is possible, however, - that the reduction in retinal luminance due to smaller pupil size also contributes to contrast sensitivity loss in older persons. In summary, reduced pupil size and loss-of focusing ability are two changes in vision that naturally occur with age. These changes, along with lens yellowing and light scattering by the ocular media, are probably the most significant changes in the older eye having some effect on an indiYidual's ability to work. Disease cannot be ignored, however, as a contributing factor to ocular changes and ~ addressed in the next section. Dmeas - Related Visual Disabilities Disease Is the most common cause of visual disability. Not only do systemic illnesses such as arteriosclerosis, hypertension, and diabetes have ocular consequences, but also the drugs used to control them can have visual side effects. Topical ocular dmeases are also more prevalent with aging. For example, the Eram~ng- ham eye study showed that acuity losses in the elderly could be accounted for by four major diseases: cataract, macular degener- ation, other retinal pathology, and glaucoma.) Ninety percent of persons age 65 and older whose better eye had a visual acuity of 20/30 or worse also had one of the four diseases. Such data clearly suggest where the emphasis (and cost-effectiveness) of prevention and treatment should be placed. David Michaeb observed at the conference that not only are the elderly prone to certain diseases, but they are also prone to the aggregate effects of illnesses whose onset is earlier and that may even be congenital. This pathological background must always be considered in the diagnosis of vision problems. Some eye diseases have major functional consequences result- ing from a loss of visual field or contrast sensitivity. Objects, obstacles, and hazards In the periphery become undetectable and ~ Leibowits, H.M., D.E. Krueger, L.R. Maunder, R.C. Milton, M.M. Kini, H.A. Kahn, R.J. Nickerson, J. Pool, T.L. Colton, J.P. Ganley, J.I. Loewenstein, and T.R. Dawber (1980), The Ft~arrungham Eye Stud Monograph Survey of Ophthalmology. Vol. 24 (Supplement) May-June.
6 mobility (either ambulatory or vehicular) becomes unsafe, par- ticularly in congested and complex environments. Indeed, Chris Johnson told conferees that when visual field loss is extensive, it can create a significant visual disability, especially for tasks involving spatial orientation or mobility skillet Johnson and his colleagues examined driving accident and conviction records of 10,000 persons for a 3-year period prior to testing to determine the relationship between peripheral visual function and driving performance.2 Persons with visual field am normalities were divided into two groups: (~) visual field loss in- only one eye and (2) visual field loss in both eyes. The driving records of age and sex-matched control subjects with normal visual fields were obtained for comparison. No differences were found in the accident and conviction rates of individuals with visual field loss in only one eye and their control group. However, the group with visual field lo" in both eyes had more than twice as many accidents and convictions as their control group with normal vi- sual fields. Johnson has concluded that binocular visual field loss is associated with poorer driving performance. Most visual disorders mentioned in this section produce a re- duction of contrast sensitivity, but, as Bailey told conferees, glau- coma and cataracts produce the most marked reductions. With these two conditions, visual acuity can remain good while contrast sensitivity can be functionally unpaired. This has substantial implications for tasks involving mobility. An example of a task requiring good contrast sensitivity ~ the recognition of steps or stairs. Often the treads and risers of stairs are made of the same material, so that it is only relative shading created by the lighting that allows the viewer to distinguish the horizontal faces from the vertical faces of the steps. The differences ~ brightness are often rather small. Bailey concluded that using steps or stairs is a sig- nificant challenge to individual with reduced contrast sensitivity, given that the task of identifying steps is one of detecting contrast differences rather than one of resolving spatial detail. In addition to the effects of normal aging of the eye, then, the functional consequences of dmease must be considered in any dim cussion of ocular changes among older workers. Restricted visual 2 Johnson, C.A., and J.L. Keltner (1983), The incidence of visual field lo" in 20,000 eyes and its relationship to driving performance. Archioce of Ophthalmology 101:371-376.
7 fields, reduced contrast sensitivity, and diminished color vision are perhaps the most significant dmease-related visual changes that influence an individual's ability to function in the work setting. Effects of Reduced visual Functioning on Job Performance It is one thing to say that an older worker may have reduced contrast sensitivity, and another to trace the unplications of such impairment to a particular job. Interviews with older workers, laboratory research, task analysis, and statistical analysis were among the techniques suggested at the conference to achieve that goal. For example, Meredith Morgan evaluated the decline in his own visual performance in a variety of tasks for purposes of the conference. Morgan told conferees: The most aggravating aspect of my vision today ~ the feeling that it doesn't work as effortlessly or as quickly as it did when ~ was younger. It seems to me that ~ must concentrate harder now and that ~ require higher levels of illumination than formerly did in order to have the same perceptual results. Just plain seeing in simplified situations, as in routine vision testing, seems as good and as quick as everbut perceiving the meaning of a complex, changing scene is definitely more difficult and slower. ~ see the parts ahnost as well as ~ ever did but the organizing of the perception as a whole seems to be more time-consum~ng and to require more attention. Self-reports by older persons about their visual problems can be of tremendous help in understanding the consequences of visual aging In work settings. Clinicians have long recognized the impor- tance of self-reporting. Michaeb repeated an old maxim: Alto define an illness, don't ask the doctorask the patient. Scientific investigators may mane significant advances in understanding the consequences of age-related changes in vision on job performance simply by asking older workers what problems they have noticed. Examples of that approach are described in the next section.
8 Surveys of Visual Problems of Older People William Kosnik reported to conferees that he and hm col- leagues at Northwestern University have developed a survey tech- nique that requires people to rate their own visual Stabilities. This survey technique provides valuable insights into the chang- ing visual capabilities of older persons in much the same way as reports by older workers themselves. Respondents, ranging in age from 18 to 95, were asked to rate how often they encountered difficulty with their derision in each situation described. The first problem area to emerge from the survey was slower speed in visual processing. This relates to the time it takes to perform a variety of visual tasks. Respondents reported that it took them more time to read than it did when they were younger. They were also less confident in performing tasks that depended on vision, such as going down steps, driving, doing hobbies, and the like. A second problem area involved difficulty seeing under condi- tions of poor illumination. Respondents reported having difficulty in distinguishing dark colors, such as distinguishing dark blue socks from black socks. Another problem area had to do with adapting to bright lights. Respondents reported having problems adjusting to bright lighting when going from a movie theater into daylight, for example. ~ order to determine how these visual problem areas change with age, Koenik divided the sample into an older group and a younger group, using a cutoff at the age of 50. The analysis showed that the older group had greater difficulty in the first two areas. These results indicate that the processing of visual input slows with age and that older people are adversely affected when lighting conditions are led than ideal. The third aggregated visual problem area, adapting to bright lights, was a complaint more commonly expressed by the younger group. In summary, the survey work described by Koenik identified several visual problem areas for older adults. The fact that older adults themselves recognize these limitations suggests that they are serious enough to have impact on the way they perform their daily activities. Of course, survey research does not specify how much illumination should be increased or how much more slowly visual tasks would need to be presented ~ order for older work- ers to perform the task safely and comfortably. Empirical research
9 is providing the answers to some of these questions. A survey approach can, however, help to identify some of the everyday vision challenges that are likely to trouble older adults. Laboratory Research Laboratory research has improved understanding of a number of problems of visual perception that tend to accompany aging and may have relevance to job performance. One example of a problem that has benefited from laboratory research ~ the decreased ability to deal with visual clutter. Robert Sekuler described for conferees a laboratory analogue to a visual problem that seems to be fairly common among older people: difficulty picking out one target from a cluster of targets. The research rests on the observation that, despite good acuity and fairly normal visual fields, an older person may experience difficulty spotting a friend in a crowd or reading a street sign In the midst of other signs. The task in Sekuler's laboratory analogue was to report where on a television screen a cartoon face had been briefly presenteda task sometimes called Radial local~zation.~ The target cartoon face was presented randomly on various meridia and at any one of three different eccentricities from fix- atione The target was foDowed by a spatially random mask that effectively limited visual processing to the period during which the face was actually on the television screen. Both older and younger observers performed equally well and virtually without error. One would conclude from these results that the two groups were equivalent in radial localization ability. However, when the target cartoon face was presented in the midst of "detractor" targets (emad rectangles), the older oh servers' performance declined precipitously; the younger observers' performance was affected only slightly. Sekuler concluded that, under conditions that mimic those of everyday life, the functional visual fields of older obser~rere appear to be dramatically con- stricted. The simulation method is another experimental technique de- signed to increase understanding of visual problems among older
10 persons. One example of simulation studies may be found in the work of Leon Pastalan.3 Pastalan's empathic mode} ~ a tech- nique that simulates selected age-related visual changes while an observer engages in various everyday tasks. Specially designed lenses worn by young observers simulate a combination of reduced retinal illumination and degraded retinal image. These lenses have a coating that both diffuses and attenu- ates (by 25 percent) the pawing light. The lenses reduce the acuity of the wearer, although the reduction is thought to underrepresent the extent of deterioration actually experienced by many older people. Participants in Pastalan's simulation studies have reported that glare from uncontrolled natural light and from unbalanced artificial light sources was the Angle most ubiquitous difficulty encountered. For matance, when participants walked up an able toward the front of a supermarket, the typical vast expanse of plate ala" across the front of the store obliterated most of the detail surrounding objects on bright days. Single intense artificial light sources produced more uncomfortable glare than combinations of less intense sources. Participants reported a number of other problems: I. Glare from uncontrolled natural light and from unbalanced artificial light sources. 2. Color fading (green/blue, most; red, least). 3. Difficulty perceiving the boundary between two contrasting surfaces, especially when two intense colors bounded each other. 4. Difficulty perceiving boundary between two related colors. 5. Depth perception was affected. 6. Adjusting to changes in illumination when moving from lighted area to dark area or vice verea. 7. hnp~rment of ability to Incriminate fine detail. There are limits to what laboratory research and simulation techniques can tell us about the vision problems of older workers. For example, one aspect of perception that has been extensively researched in the laboratory from the perspective of aging con- cerns the speed or rapidity of perception. Speed of perception 3 Pastalan, L.A. (1982), Environmental design and adaptation to the visual environment. In R. Sekuler, D. Kline, and K. Dismukes, eds., Aging and Human V"uat FUnchor~ New York: Alan R. Liss, Inc.
11 has been investigated with a number of laboratory procedures; the universal finding in research of this type is that adults with average ages in the sixties and seventies are either less accurate or require significantly longer durations to achieve the same degree of accuracy than adults with an average age of about 20. Because the rapidity, selectivity, and integration of perception are likely to be important elements in many complex occupational tasks, one might expect to find pronounced age-related impa~r- ments in a great many job activities dependent on quick percep- tual processing. In fact, however, there have been remarkably few well-documented, age-associated decrements in job performance. Notable exceptions are in the areas of professional athletics and certain jobs with severe time stresses. For the most part, one is struck by how few age effects have been found In actual work performance in which quick perceptual processing ~ involved. Tunothy Salthouse suggested to conferees that there might be several possible reasons for this failure to find age differences in work effectiveness comparable to those observed in laboratory studies. Laboratory averments may be more demanding than the evaluations typically performed concerning job effectiveness. It ~ also possible that adults, particularly older adults, are more motivated to perform well in their work activities than In the rather abstract tasks encountered in most research laboratories. A third interpretation of this discrepancy between laboratory and the workplace relates to the amount of experience people have hut on the tasks in which performance is being evaluated. Because many laboratory tasks are deliberately designed to minimize the influences of experience outside the laboratory, they can be consid- ered to consist of comparisons ofnovices. However, because most people have spent thousands of hours performing the activities of their job or daily life, they can be considered to be experts in these activities. Thus, results from the laboratory may not be general~zable to real-worId situations. David Walsh concurred with the view that the Wife connec- tion needs to be strengthened. He suggested that more knowledge is needed about the fragility of basic information processing mea- sures as predictors of everyday seeing. Knowing what to assess will also depend on the importance of particular stages of perceptual processing to a specific job. Finally, Walsh suggested, we need to know more about the underlying causes of perceptual changes.
12 Walsh added, as did a number of other conferees, that another important problem ~ that of individual differences. Not every older person shows the same decrement in a perceptual task, and a few older people actually perform a task better than some younger people. The primary implication is that investigators must take into account in designing their experunent that chronological age is not a very strong predictor of an individual's visual performance. In summary, laboratory research, surveys, and simulation -methods can contribute to understanding of the vision problems encountered by older workers as they age. Scientists will, however, have to addre" two significant methodological issues if the find- ings from such research are to have practical application. The first challenge is to develop better matches between visually oriented laboratory took and the real-worId tasks being studied. The other challenge is to arrive at abetter understanding of the factors that account for the high degree of individual differences reported by many investigators. On-Site, On-the-Job Research Although some data are available regarding visual ability and driving performance, for other jobs that are predominantly visual in nature~uch as visual inspection tasks or work at video display terIIiinals the data are limited on how performance is affected by changes that occur in vision with age. Pauline K. Robinson told conferees that the issue concerns the value of keeping older workers in the work force longer. Employers may find that the most con- vincing evidence for changing their employment practices comes from on-site, on-the-job research that measures visual decline and task performance. Although data are limited regarding how changes in visual function affect the performance of specific tasks, conference par- ticipants reported on one or two studies that have advanced un- derstanding of this topic through field research. James Fozard described a study carried out by the National Institute on Ag- ing's Gerontology Research Center that sought to minimize age differences in performance through optional office lighting. The investigators found that by increasing the illuIriination level in the office, the performance of clerical workers improved, with greater improvement evident among the older workers. Both groups ex- pressed a preference for higher levels of illumination, but only the
13 older group reported greater eye comfort at the highest light level used in the study. This type of field research, according to Fozard, could significantly increase understanding of the specific vision needs of older workers. The Acuminating Engineering Society of North America (TES) has conducted on-~te task analyses to guide the development of lighting recomunendations in a variety of settings, including the work setting. Such analyses may provide a useful starting point for researchers interested in on-the-job studies of vision among older workers. Alan Lewis, who is chair of the committee on lighting stan- dards of TES, explained to conferees that when illumination leveb are established by the lES for a specific location, the recommen- dations are developed through a multistage process. For interior spaces, such as offices, the procedure starts with the identification and classification of the visual task into stack categories" that have broad illurninance requirements based on task contrast, size, and duration. At this stage, the illum~nance recommendations consist of a range of values; the selection of a value within the range is based on weighting factors that depend on: (~) the average age of the worker In the space, (2) the demand for speed and/or accu- racy, and (3) the task background reflectance. For the age factor, a certain number is amigned to ages under 40, another aligned to ages 4() 55, and yet another ~ aligned to ages over 55. This factor is included to acknowledge the fact that older persons suffer from increased disability glare and have reduced contrast sensitivity. As an example, a typewritten page calls for an illumin~ce of from 200 lux to 500 lux. If the worker's age was 60 and the demand for accuracy was anportant, the illum~nance recommen- cation would be 300 lux. The recommendation for a worker age 30 performing the same task would be 200 lux. Thousands of tasks have thus been analyzed by the lES, al- though I.ewis added that the illuminance selection is only a start- ing point in the lighting design process. Freedom from direct glare and veiling reflections, color considerations, and myriad other fac- tors are every bit as unportant to the effectiveness of the lighted space as ~ illumination level. A leper amount of good quality iBum~nance can often be far more visually effective than a larger amount of light from a poorly designed lighting system. Guidance
14 on potential problems and recommended solutions for particular types of spaces can be found in the lES publications.4 One of the greatest challenges to investigators interested in the effects of age changes in vision on job performance is the role of prior experience in visually guided tasks. Sara Czaja told con- ferees that, if we look at an,~nspection task and break it down into task componentsvisual search (in which one searches an item, a target, or a flaw) and decision making fin which one sees something and decides whether it fads within acceptable standards), a non- intuitive result occurs. One would expect age decrements on those kinds- of tasks based on the reports in the literature. However, the data are limited and far from conclusive. One study found a slight age-related decline in the ability to d~scrimin ate between flawed and unflawed items; another reported no age effects; and a third showed a decrease In inspection error with age. According to Czaja, recent studies suggest that the amount of decrement in vi- sual search tasks may depend on familiarity with the task. In other words, well-practiced visual search activities may not exhibit age- related decline. Clearly, cognitive factors such as skill level need to be taken into account in any study of the impact of visual changes on task performance, as Salthouse also demonstrated. Statistics Reporting Systems As Stephen McConnell told conferees, there is a perception among lawmakers and the genera] public that because people are living longer, they are healthier. We really don't know if this assumption is correct or what people mean by the term healthy. Several studies indicate that workers are retiring from the labor force at much younger ages than previously. They may chose to do so to enjoy the benefits of good health in their retirement years or they may decide to retire because of health problems. DecIm~g vision could well be among those reasons why older workers leave the labor force, whether voluntarily or involuntarily. IN a paper prepared for the conference, Herbert Panes ret ported that the average retirement age ~ now about 62, and for large corporations it ~ closer to 59. Why do workers retire? In 4 Kaufman, John E. ed! (1984), INS Lighting Handbook. Rcfcrcnec. New York: Illuminating Engineering Society of North America; (1987), INS Lighting Handboolc: Application. New York: Illuminating Engineering Society of North America.
15 recent years the mandatory retirement age in many occupations has been increased from age 65 to 70. Parnes, using evidence from longitudinal surveys, found that, of ahnost ~ million retired men between the ages of 60 and 74, only 3 percent were required to retire. As many as 56 percent of the retirees appear to nave freely chosen retirement, and 35 percent had retired for reasons of health. While Parnes acknowledges that there is a conceptual problem in distinguishing between retirement for reasons of health and voluntary retirement, his longitudinal evidence indicates that the categorization is sound. Some of the retirements for reasons of health have to do with defective vision, but it is difficult to find the data that indicate the extent. Certain federal statistical reporting systems may have a role in understanding how declining vision influences job decisions among older workers e Richard Burkhauser described the results of a pseu- doclinical study that one of hm students conducted using data from the Social Security Adm~nistration.5 Mitchell was interested in the effects of the early onset of arthritis in work force partic- ipation. She found that individuals who developed arthritis at age 40 stayed in the work force 12 more years on average. The comparison group, who reported no health impairments at age 40, stayed in the work force 23 more years. Burkhauser suggested that similar studies might be conducted to deter~nine the effects of the early onset of visual imp averments on work force participation by age. The data from a number of surveys carry information about prevalence of visual impairment, disability, and employment hand- icap and were described for conferees by Coronae Kirchner. As she pointed out, however, there are many problems with these data of which investigators should be aware. The terms pathology, impair- ment, disability, and handicap mean different things in different surveys. Most surveys have neglected the older population because that group has not been considered of importance; the samples are not always sufficiently large or representative of the older popu- lation. Still, the data bases (Table I) could be of considerable interest to investigators. ~ Mitchell, Jean M. (1986), The Eject of Arthritis in Work Behavior. Unpublished doctoral dissertation, Vanderbilt University, May.
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17 Ronald Wilson told conferees that the 1990 census may carry questions about conditions (including visions that limit working, driving, and the like. These questions are being pretested at the present time and, if included in the 1990 census, could be another source of information for studies in this area. VISION SCREENING PROGRAMS IN T H lo WORKPLACE Data are inadequate on many problems that relate to visual impairment, aging, and the workplace. But no lack is more keenly felt than the near-total ignorance about the policies of large Ameri- can companies in this area. Of particular importance are company policies on vision screening. For example, what do large compa- nies do to screen their workers' vision? What steps are taken for periodic vision testing? What procedures are available for adjust- ing the workers' job environment in order to accommodate visual problems? Some answers to these questions were provided by two confer- ence participants representing companies with active vision care programs. Roberta Alex of Convair Division, General Dynamics Corporation, a defense contractor, described the screening pro- gram at that company. Alex explained that preplacement screen- ing examinations are performed to match the physical capabilities of an applicant tenth available jobs. Such a match considers job related physical requirements, the work environment, and the safe performance of the job. The physical examination includes a com- plete history and physical examination including visual acuity. The medical services office also routinely performs several thou- sand visual acuity certification tests on employees each year. If presbyopia develops, employees are required to obtain prescription lenses to meet job requirements. Alex added that employees may take advantage of the eye care program that provides a complete examination, lenses, and frames at a discount. Louise Birkholz of the Chicago-based SAC Electric Company described that company's program. The company has been in business since 1911 and manufactures high-voltage switches and fuses used by electric utilities and other large power consumers. S&C's company-sponsored v~ion-protection program dates back over 30 years. In the early 1950s, this company made the d~ cision to provide all employees with "appropriate" safety glasses
18 (prescription glades, if necessary). An optometrist came to the plant and gave eye examinations to all employees. To make the eye examination process as easy as possible, appointments were scheduled during working hours, minimizing excuses not to keep appointments. Plano and prescription safety glasses were then purchased by the company for employees in need of them. Following that initial round of examinations in the 1950s, the optometrist currently visits the company once or twice a month for follow-up examinations and examinations of new employees. An ophthalmologist ~ on call in case of eye injury or if special eye problems are detected by the optometrist. Employees receiving S&C-sponsored eye examinations include all new employees In manufacturing areas. For all employees age 60 and over, the company sponsors annual physical examinations in addition to the annual eye examination. Employees who are vehicle operators, such as forklift drivers, and all employees who work in the solid-state assembly area are examined annually. Em- ployee~ in manufacturing are" are examined once every two years, or sooner if necessary. The management of both SAC Electric and Convair consider their vision programs cost-effecti~re. The companies believe that the expense of running the vision programs is offset by improved productivity, retention of highly experienced workers, and job satisfaction. There are ways for workers with vision problems to receive care other than through their place of employment. If they are veterans, they may turn to the Veterans Administration (VA). Joseph Maino described one such program. VICTORS (Vision Impairment Cen- -ter to Optimize Remaming Sight) is a low-vision rehabilitation program designed to optimize services to the partially sighted and complement exiting eye clinics and blind rehabilitation centers. VICTORS' main goal is to keep working veterans on the job and return unemployed veterans to the work force. The VICTORS staff: (1) assists the visually unpaired veteran to optimize remain- ing vision, (2) suggests ways to modify work conditions or job task to better suit veterans' abilities, (3) refers eligible veterans for vocational rehabilitation training, or (4) refers veterans to state vocational rehabilitation agencies. The VICTORS staff works in concert with employees, employers, and state and VA vocational agencies to keep individuals in the work force.
19 Screening procedures are often inadequate to determine whe- ther an older individual's vision is suited to a particular job. Special problems may arise because older people fail to meet the prevailing vision screening standards that have been laid down as requirements for the job in question. This may lead to a person's being removed from the job or for the visual requirement's being waived. Of all the criteria of visual performance, acuity is the sim- plest and the most widely used. As Michaels told conferees, it is true that the SneDen chart ~ poorly standardized, poorly cali- brated, and sometimes poorly administered but it is surprisingly reliable in detecting problems, and, after a century of use, it has maintained that reputation. Bailey called attention to the fact that automated vision screeners have only one standard target luminance level, which might not be representative of the illuminance conditions at the job site. Instrumental vision screeners incorporate collections of tests that have usually been shown to be good at identifying visual capacities in young people. Many of the near-vision tests presented on instrumental vision screeners demand that the eye focus to a given close distance. The older person may not have a reading prescription adjusted for that particular distance. Furthermore, the near-vision distance chosen for the screener may not represent the working distance commonly used in the workplace. Ideally, every older person should have visual field record, according to Michaels, but sometimes this is not always practical. Visual field testing is recommended for any older person who gives headache as a primary complaint and who reports flashes, floaters, or cur- ta~ns in the visual field. Although different parts of the visual field interact as a whole, central fields should be separated from peripheral fields in testing. Donald Kline pointed out that as we learn more about the changes in the visual processing among older people and the sig- nificance of those changes for work performance, certain visual processes will logically emerge as candidates for testing. These include dynamic visual acuity and motion detection, visual field size, glare and glare recovery, distance perception, and visual search (which are taken up in a later section). In summary, more information is needed regarding vision screening programs in U.S. companies. It is likely that visual acuity testing is the most widely used vision screening procedure
20 in the work setting. While visual acuity testing serves an im- portant role in measuring a certain aspect of visual performance, many other aspects of vision can and should addressed. MATCHING WORMERS AND JOBS Once the visual requirements of tasks are identified and suit- able vision screening procedures are in place, appropriate job placement for ad workers, including those with vision Innitations, are essential. The Physical Placement Program of General Dynam- ics Corporation's Convair Division is an example of a program that strives to place workers in appropriate jobs through an elaborate coding system. Physical placement codes are applied to employees with physi- cal limitations to ensure that they are compatible with the assigned job classification, so that health problems will not be aggravated by the job and safe work conditions are provided for all employees. Alex reported to conferees: For instance, if a person has severe arthritis in his knees, he cannot, of course, be crawling around a fuselage drilling holes; he cannot climb ladders. If a person has a visual problem- monocular vision, let's say we have a code for that. Everyone in our plant with monocular vision must wear either prescrip- tion or piano safety glasses.... We have areas where people are doing final assembly. We certainly want to make sure that those working in final assembly have depth and color vision. . . . We want to make sure they are not diabetic; we want to make sure they don't have epilepsy; we want to make sure that they don't have any tremors in their hand. We look at the whole person, but we do pay great attention to the eyes. Table 2 provides a sample of the physical placement code definitions used by General Dynamics. The physical placement code assigned to an employee, according to Alex, signifies realistic physical limitations or potential hazards. Such a system may well have application in many other job settings. The physical placement program described by Alex is not age-specific, although many medical problems that often accom- pany aging are probably captured by that system. In all likelihood,
21 TABLE 2 Example of Phy~c~ Placement Code Definitions Category Symbol Definition General Physical Capacity Code U Specific Limitation or Restriction Code Unlimited Worker must not lift or exert effort over 35 pounce Worker must not lift or exert effort over 25 pounce Worker must not lift or exert effort over 10 pounds Worker must wear safety glasses at all times while on company property 1R 17 Worker must wear prescription lenses at all times while mooring about on company property Worker's job must allow 40% sitting in performance of job tasks Worker must not be assigned work in which distance or depths must be judged accurately Worker must not work in position in which accurate color vision is essential _. _ Based on Physical Placement Code Definitions, Convair Division, General Dynamice Corporation (R. Alex' 1986~.
22 any physical placement program could be improved by the addi- tion of visual screening procedures that more effectively capture job-relevant vision functions that change with age. WORKPLACE DESIGN The design of the workplace should allow workers, including those with vision problems, to perform required visual tasks effi- ciently and comfortably. In indoor office and factory workplaces, the major limitation on visual functioning typically results from a relative lack of illumination. As Kosnik pointed out, dunly lit environments may differentially impair performance of older work- ers. "The older worker's performance will be doubly compromised if small sized print, meters, labels, scales, or charts have to be read in poor or dim illumination. Localized, adjustable lighting for the work task can help older people by compensating for smaller pupil size. As Bailey pointed out, however, special care should be taller in providing extra illumination for older people so that glare is not introduced. Roberta Alex reported that Convair's Safety Department per- forms lighting surveys at workstations when requested. Con- vair can accommodate visually impaired employees by provid- ing supplemental lighting, magnification loops, or high magni- fication/high intensity portable inspection lamps. To illustrate further how Convair accommodates employees' vision needs, Alex described two case studies. In the first case, a 5~year-old man three years short of retirement developed diabetic retinopathy. The supervisor referred the employee to the medical services of- fice; it was established that the employee was under the care of a retinal specialist. The company, in consultation with the em- ployee and the union, placed the employee on permanent day shift to provide better lighting conditions. The firm also changed his job from drill press operator to machine parts finisher to eliminate work involving fine detail. In another case, a secretary who had been employed 19 years developed cataracts. She referred herself to medical services, according to Alex. She wanted to continue working for the six-month period preceding surgery. The action that was taken by the company was to provide the employee with a desk lamp and high intensity spotlight and to assign lengthy typing projects to other employees.
23 Another factor that may limit the performance of older work- ers is slowed processing of visual information, which manifests itself in a number of ways. According to Kosnik, "visual informa- tion that is scrolled on a video monitor may have to be displayed for a longer time in order to be read. Performance on externally paced visual tasks may show an age sensitivity that would be quite unexpected on the basis of ocular parameters alone." This is not to say that age-related changes in oculomotor parameters are not also of potential significance. For example, the vergence, pursuit, and vestibular-ocular response systems all may slow with aging and give rise to an apparent need for greater processing time. Walsh added, however, that "differences in the duration of an internal representation of a particular visual display are likely to have relevance only for work situations associated with sac- cadic eye movement such as reading or visual search. In most real-worId viewing situations, the eye is free to select continued external input until perceptual recognition is complete." Walsh believes that everyday seeing is more affected by age differences in selective attention. "Consider the task of a person faced with way-finding in an urban environment. Present on the retina of the eye is a complex pattern of light containing sets of features for to-be-recognized landmarks, street signs, terrains, etc. In order to orient and direct themselves through this space, the person must scan and process a rich array of elements. Assuming that each element is recognized after it is selectively attended to in a sequential fashion, a slowing of attentional selection would work in a cumulative way to slow performance. The implication in the work setting, according to Walsh, might be evident in the work of a person operating complex equipment, a situation in which slowed selective attention may lead the operator to be unable to function adequately. Changes in vision with age suggested to a number of confer- ees the need to consider training and retraining procedures for older workers. Czaja reported that the pervasiveness of computer technology means that many workers have had to learn to inter- act with computers on a daily basis. Czaja's research has shown that commercially available training strategies used to teach word processing are not effective for older learners. Czaja observed: "Perhaps even more basic are questions regarding the suitability of computer tasks for older persons. Few studies have examined whether there are age differences in task stress as a function of age
24 of the operator. These are import ant msues, as the number of jobs involving computers wall continue to increase, and this will unp act on the employment status of older persons. Unless we develop effective retraining strategies, older persons will not fit into the new work environment. If visual functioning ~ substantially reduced over time, espy cially due to disease, there are many changes that could be made in the workplace to keep workers with these problems on the job. It is useful to note that many individuals with macular disturbances often have an unusual need for strong illumination, according to Bailey, and that rather modest increases in illumination can some- tunes have profound effects on visual performance. In a paper prepared for the conference, Samuel Genensky pointed out that nearly all partially sighted people who have had appropriate visual aids prescribed, who are properly trained in the use of those aids, and who are motivated to use them, scan successfully perform such sight-intensive tasks as reading ordinary ink printed material, writing with a pen or pencil, moving about safely and alone in even an unfamiliar environment, ~d viewing a chalkboard or other distant Replay." The types of aids available to workers with limited sight are taken up in the next section. Hilda Kahne told conferees that it is important that any efforts to increase the employabilitiy of workers include a consideration of changes in job design, such as part-time employment. Kahne observed, "I am not sure how much the availability of part-time work will solve the problem for the visually impaired," although there would seem to be a role, in her opinion. In summary, although much remains to be learned, there Is already considerable information available on visual processing changes that occur with age. The information in had needs to be disseminated and discussed so that appropriate changes can be made eventually in the employment setting to benefit older workers. RESPONDING TO TO VISION NEEDS OF OLDER WORKERS Employers can save considerable time and money in building and sustaining a productive work force through health care and employment policies in which vision has been given a prominent role. In this section, we discuss what needs to be done to assist
25 employers in improving or introducing programs that take into account the changes in vision that occur with age. In discussing procedures for responding to the vision needs of aging workers, we lay out the steps necessary to make vision screening, job placement, and environmental design suitable for the changes in vision that occur with age. Estimating the Visual Requirements of Jobs Employers motivated by safety considerations have developed a profile of the physical requirements of certain jobs, although the extent of that practice is not known. Information presented at the conference suggested that the visual performance characteristics identified by some employers apart from acuity- include color vision and depth perception. While not age-specific, it is known that many of these visual characteristics are susceptible to age effects. Scientific findings on the visual processes that are susce~ tible to age effects and that are involved in visually guided tasks could help better identify visual requirements of jobs. This in turn might thereby enhance the employment of older workers. Corre- sponding to these other visual requirements are the age-sensitive visual skills of contrast sensitivity, glare and glare recovery, speed of visual processing, dynamic acuity, and night vision. Employ- ers motivated by safety considerations and employers motivated by productivity concerns may eventually have at their disposal a framework for estimating the visual requirements of any job. Vision Screening Research suggests that workers engaged In visually guided tasks may experience a number of problems with their vision as they grow older. These problems may interfere with the perfor- mance of those tasks. Smaller pupil size and lens yellowing affect the amount of light reaching the retina. Loss of accommodative ability creates limitations on the range or working distances for which the eye can be used. Glare from uncontrolled light sources may present a problem, and slower visual processing speeds may make it more difficult for the older worker to deal with cluttered visual scenes, rapidly presented visual information, or detail (espe- cially in conditions of poor illumination). Diseases affecting sight,
26 furthermore, may substantially reduce the visual fields of older workers. Although information is generally sketchy about the vision screening practices of American companies, it is probably the case that acuity testing is the most widely used screening procedure in preplacement and preemployment examinations of older workers. Depending on the visual requirements of the job, a number of vision screening procedures are recommended beyond acuity test- ing. Contrast sensitivity testing determines the threshold contrast required to detect objects (typically gratings) of varying spatial structure (spatial frequency). Acuity under low illumination can be measured using a variety of available techniques. Dynamic visual acuity is measured using acuity optotypes (such as Snellen letters), but under conditions in which these optotypes are moving and the observer must track them. The greatest drawbacks tothe implementation of these procedures are: (1) the possible low feasi- bility of testing for these visual skills in preplacement or periodic screening examinations, given the tune and/or sophistication of the equipment involved, and (2) the experimental nature of some of these procedures. Job Placement Once the vision requirements of the task have been specified and suitable vision screening procedures are available, employ- ers and workers can benefit from the appropriate match between workers and jobs. Physical codes can be developed for certain jobs that spell out precisely the expected visual capacity of an employee to work at that job. While not age-specific, many of the visual performance characteristics that will have been identified will be those in which age-effects are known to occur and be measurable. It was evident from the conference, however, that many vi- sual skins that change with age can be compensated for through adjustments in the design of the job, in the work environment, or through training. Hence, job placement procedures, practically speaking, may be used only in those situations in which a change in the task or the work environment is infeasible or the retraining of the worker is not advised for safety reasons.
27 Environmental and Job Design Employers sensitive to the changing visual needs of older work- ers can improve the safety and productivity of workers in a variety of ways. For nondisease-related visual changes, the older worker may benefit from better ibum~nation, more contrast in the mate- rial being used, reduced glare, larger print, and the like. If disease has led to more severe visual impairment, available options include part-time employment, job or task reassignment, or the provision of vision aids and retraining. Economists at the conference ar- gued that special workplace accommodations that result in worker retention are more cost-effective in the long run.
