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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
OCR for page 2
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 workers—changes
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
OCR for page 3
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.
OCR for page 4
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
OCR for page 5
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.
OCR for page 6
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.
OCR for page 7
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 ever—but 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 doctor—ask 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.
OCR for page 8
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
OCR for page 9
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 presented—a 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
OCR for page 10
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.
OCR for page 11
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.
OCR for page 17
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
OCR for page 18
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.
OCR for page 19
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
OCR for page 20
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,
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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~.
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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.
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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
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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
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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,
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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.
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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.
Representative terms from entire chapter:
visual field
