Work, Aging, and Vision Report of a Conference (1987) / Chapter Skim
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1 Nature of the Problem
1 Nature of the Problem
Pages 1-27
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Screening procedures are often limited to visual acuity testing, although other facets of vision may be tested given the physical 1
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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 workers—changes that could impair job performance.
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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.
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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.
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Some eye diseases have major functional consequences resulting from a loss of visual field or contrast sensitivity. Objects, obstacles, and hazards In the periphery become undetectable and ~ Leibowits, H.M., D.E.
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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 inonly one eye and (2)
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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.
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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.
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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.
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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.
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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.
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Employers may find that the most convincing 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 participants reported on one or two studies that have advanced understanding of this topic through field research.
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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.
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In other words, well-practiced visual search activities may not exhibit agerelated 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.
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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 pseudoclinical 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 participation.
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The physical examination includes a complete history and physical examination including visual acuity. The medical services office also routinely performs several thousand visual acuity certification tests on employees each year.
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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.
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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)
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MATCHING WORMERS AND JOBS Once the visual requirements of tasks are identified and suitable 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 Dynamics Corporation's Convair Division is an example of a program that strives to place workers in appropriate jobs through an elaborate coding system.
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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.
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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 workers.
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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 saccadic 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.
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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 sometunes 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.
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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.
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Depending on the visual requirements of the job, a number of vision screening procedures are recommended beyond acuity testing. Contrast sensitivity testing determines the threshold contrast required to detect objects (typically gratings)
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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 argued that special workplace accommodations that result in worker retention are more cost-effective in the long run.
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