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Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
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OCR for page 28
2
Solutions
If employers know about or had access to the information
reviewed at the conference, they would be able to unprove or
introduce programs that take into account the changing vision
capabilities of their workers. The preceding section described work
that needs to be done by the scientific and business communities
before such programs can be put into place in their entirety.
But employers need not wait. There are many steps that
could be taken now to improve the performance of workers based
on current knowledge. This section identifies some of the possi-
bilities raised by conference participants, which include providing
suitabIc sometimes very inexpensive visual aids for older work-
ers; providing opportunities for training and retraining on the
job; raising illumination; introducing other selected modifications
in the design of the work environment; adopting certain avail-
able screening procedures; and redesigning jobs. Taken separately
or together, these actions could bring enormous returns to both
workers and employers.
COMPENSATING FOR DECLINING
VISUAL FUNCTION
In 1890 William James published a psychology text that even
now, nearly a century later, contains many powerful insights.
Among them ~ a proposed general law of perception: Whilst
part of what we perceive comes through our senses from the object
before us, another part (and it may be the larger part) always
comes out of our own mind."
28
OCR for page 29
29
Though one may not agree with James's claimed proportions-
it may not be the larger part of perception that comes out of our
own mmds—it ~ hard to deny that the act of seeing draws on far
more than just the neural information that ~ momentarily avail-
able from st~rnulating the eyes. A number of studies suggest that
the past experiences that older people are able to draw on in the
performance of certain tasks may overcome certain age effects in
visual function. Practice ~ the principal agent creating important
skill differences between experienced and inexperienced workers.
And the expertise that comes with practice ~ certainly among the
older worker's strong suits.
One such study, reported by Salthouse, examined transcrip-
tion typing, that is, typing from printed copy.6 This is an interest-
ing activity from our current perspective because there is a large
number of typists at many leveb of experience at all ages, and
typing is a perceptual-motor skill that laboratory results suggest
declines with age. However, the Salthouse study yielded some
surprising results.
Typists ranging from 19 to 72 years of age and with a range of
typing speed from 17 to 104 net words per minute participated in
a series of typing-like tasks. The sample was deliberately selected
to result in a near-zero correlation between age and typing skill
because the primary research question was not whether typing
speed declined with age, but rather what were the differences
between typists of different ages with the same overall level of
skill.
Two of the initial measures obtained from each participant
were the average time between successive keystrokes (interkey in-
terval) while perfortn~ng normal typing, and the average time
between keystrokes while performing a standard reaction time
task. These activities are structurally quite similar in that both
involve rapid keystroke responses to visually presented alphabetic
characters, but the stimuli in the choice reaction tone task were
presented discretely, with the next stimulus presented only after
the response had been registered from the previous stimulus. The
important finding to note from this study is that the age trends
differ substantially for the two tasks despite considerable super-
ficial similarity. Performance on the reaction time task exhibits
6 Salthouse, T.A. (1984), Effects of age and skill in typing. Journal of
E~crimcntal Psychology: Gcncral 113:345-371.
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30
quite typical age-related increases indicating poorer performance
with increased age, yet performance of these same individuals on
the typing task was virtually independent of age.
Subsequent manipulations in the project were designed to ad-
dress two questions: (~) Why ~ there no age trend in the speed
of typing when there ~ a pronounced age trend among the same
individuab in the speed of responding in reaction tune task? and
(2) Why are people of all ages so much faster in their keystrokes
in typing than in reaction tune? Tentative answers to these ques-
tions came from a variation of the test, In which the number of
preview characters in the display was systematically varied while
typing; the average interkey interval was then measured as a func-
tion of the size of the preview window. The results indicate that
average interval between keystrokes increases as the number of
visible characters decreases below about 7 characters. This fi~-
ing suggests that skilled typists begin processing characters to be
typed well in advance of the current character. In fact, if only a
single character ~ presented and typists are prevented from using
this type of anticipatory processing, performance closely resem-
bles that characteristic of the reaction time task. An examination
of the age trends on these measures suggested to Salthouse that
older typists employed a form of anticipatory processing to com-
pensate for their slower perceptual-motor processes. This finding
resembles those of Czaja.7
Other types of compensatory skills were described at the con-
ference by Morgan:
When ~ go from outdoors to indoors, it takes me much longer
than anybody else in my group to find out what's going
on.... ~ am relatively more certain that ~ don't see as well
anyway, no matter how weld ~ dark-adapt. ~ also notice that
have some difficulty separating blue colors. ~ can't tell some-
tunes whether the thing is lavender or pink. It so happens that
in time ~ can arrive at the correct conclusion by introspection:
if ~ am certain of the color, it's probably lavender; if I'm not
certain, it's probably pink.
~ don't have as much trouble driving at night as one might
think. Because ~ expect to have trouble driving at night,
have cut down my night driving. But ~ have great difficulty
7 Czaja, S. and C. B. Drury (1981), Age and pretraining in industrial
inspection. Nunwn Factors 23:485-494.
OCR for page 31
31
driving at twilight e In part, it is due to the fact I have great
difficulty In visual search, in finding the particular area the
scene that I want to pick out that makes sense to me. I've
gotten into the habit of taking a dry run to somebody's home
that I have never visited before. I will drive to it in the middle
of the afternoon to find out where it is, so that I won't get lost
getting there in twilight.
The ability of older workers to develop compensatory skills
and the role of practice should never be underestimated when
considering visual changes among older workers.
BETTER VISION SCREENING PROCEDURES
Screening tests are often used to determine whether an indi-
vidual's vision is adequate for a particular job. Vision screening
procedures, however, "e often not very job specific.
Kline reviewed a number of visual screening procedures that
may be of interest to employers. In older workers, effective visual
field size may be reduced, which argues for the inclusion of visual
field tests in any screening procedure. At the present tune, a few
states require a visual field determination for a driver's license.
As Michaels pointed out, every patient should have visual field
records, but this is not always practical. As visual field extent
is shown to be of importance in jobs involving visual search, for
example, or in information-dense scenes, visual field testing may
become more desirable and thus a standard part of screening
procedures for older workers.
Many visual screening procedures that could be used by em-
ployers are still In the experimental phase. The contrast sensitiv-
ity function (CSF), for example, provides a more comprehensive
statement of spatial vision abilities than do more traditional acuity
measures, according to Kline. It does so by determining threshold
contrast required to detect objects (typically gratings) by varying
spatial structure (spatial frequency). It is likely that some work
tasks depend more on intermediate spatial frequencies that are
better assessed by the CSF than by standard acuity tests. Unfor-
tunately, as Kline points out, although work is proceeding in this
direction and test patterns are readily available, the diagnostic
value of the CSF has yet to be demonstrated for such tasks.
OCR for page 32
32
Standard acuity testing gives little indication of a person's
ability to distinguish detail in a rapidly moving object. More con-
sideration should be given to tests to assess the visual fitness of
older workers for tasks involving discrimination, such as occurs in
driving or In ~moving-part" industrial operations. Such standard-
ized tests have yet to be developed, however.
As Michaels pointed out, the examination of the aging eye
does not differ in essentials from that of any other eye except
that it takes more time, more tact, and more patience. fit takes
more time because older people frequently have many nonspecific
complaints, poorly expressed, and sequentially muddled. Some
symptoms may go unreported because of memory loss, fear, or
indifference. It takes more tact because, in the nature of things,
some senescent diseases are not only chronic but irreparable. It
takes more patience because the aged eye often suffers multiple
defects which must be sorted out. As more consideration is given
to the introduction of more or different procedures to screen the
visual capabilities of older workers, some thought will need to be
given to the question of who wiD administer the tests and decide
which tests are needed. A great deal of sensitivity should be
applied in using procedures that may rame concerns about vision
functions that heretofore have not been given much thought by
most workers.
PROVIDING VISUAL AIDS
What simple changes might be made in the workplace in
order to accommodate visually Unpaired workers? There are many
simple magnification devices and techniques that can be put to use,
such as a device to increase the relative size of the material to be
used.
Bruce Rosenthal illustrated the point that it ~ possible to be
quite clever in meeting people's vision needs:
~ would like to tell you what happened with one of my patients
who is 84 years old. He was flying out to the West Coast to
work on a case. He ~ a lawyer, and it was a $350 million
case. He said, ~I really would like to have some notes with
me. What can ~ do? ~ don't want to use my lens because
have to hold it up very close. He really didn't want to use
his high-powered lens because he didn't want to have anybody
OCR for page 33
33
look at horn askance and think he really didn't know too much
about the case. What we ended up doing was something very
simple that everybody here can do. We got hold of one of the
newer copiers which magnifies about 22 percent. We sent his
notes through the copier once, a second time, then again.
think we did it about 20 times. He ended up with a few letters
on 11~ x I8~ size paper. That solved his problem. He brought
reams of paper into the courtroom, and he won the case.
Another technique involves moving the object toward the
viewer's face, in effect, magnifying the image on the retina. There
are high-powerec} reading spectacles that focus for a Chinch work-
ing distance, although some people function much better using a
hand magnifier. Stand magnifiers are devices that have plus lenses
that are built into rigid housings. These are useful for arthritics
or people who have a difficult time holding the lens steady, since
the magnifier sits in a rigid housing.
Genensky, In a paper prepared for the conference, also iden-
tified the role of closed circuit television as a versatile visual aid
currently available to partially sighted workers in some settings.
Closed circuit television permits the control of the magnification of
material seen on the screen as well as its brightness and contrast.
Simpler nonoptical aids are also available. The typoscope LS
certainly the simplest aid. This a piece of fairly stiff cardboard
that is rectangular in shape and contains a rectangular slit or
window in the middle. The typoscope is usually small enough to
encompass all or a portion of a few lines of print when it Is placed
on a page. Morgan observed: ~! very seldom find reported in
the literature the problem of spatial interaction In reading printed
material. It ~ the lack of border on the printed page as much as
the fact that there ~ lack of space between the words and between
the lines that makes it difficult to read. One of the solutions to
the problem ~ a typoscope.... ~ need a white typoscope. ~ put
it down on the paper, and ~ immediately increase the contrast
between the print [and the background). Now ~ have a nice, white
background, which allows me to figure out the line of print."
In summary, many optical aids are available to augment de-
clining sight.
OCR for page 34
34
RETRAINING OLDER WORMERS
The compensations older people make in response to declin-
ing sensory functioning suggest that learning, and therefore sys-
tematic training or retraining programs, could be helpful with
respect to the visual performance of older workers. To what ex-
tent can training be used to approve performance directly through
the development of compensatory strategies? Czaja reported at
the conference that research has shown that appropriate training
strategies can often enhance the task performance of older persons.
Several studies have shown that a problem-solving discovery ap-
proach that munimizes rote memory is effective for older learners.
It is also important to provide learners with immediate feedback
to maximize the unlearning of incorrect responses and also to give
them enough time to avoid deleterious pacing effects. Successful
learning is important both ~ its own right and in helping to avoid
negative attitudes that act as a barrier to the acquisition of new
skins.
Learning and training are important areas to consider. And
the issue of aging and training, which has not been examined very
much from an industrial point of view, should be addressed from
two different perspectives. The first is training in learning strate-
gies. Czaja reported on evidence that suggests that the elderly
are led likely to use cognitive strategies or learning strategies:
Tithings like mnemonic aide and mediators and organizing learn-
ing material. We have done some research on training older people
to perform industrial inspection tasks. One thing we found was
that providing them with Retraining on component skills that
were relevant to the inspection task carried over later to subs
quent inspection performance. We tried to provide pretraining and
learning to learn kinds of skills, like organizing material, making
size judgments, and the like."
The second perspective concerns how to train people for spe-
cific tasks. Czaja and her colleagues found that the success of older
people In learning to perform new tasks or new jobs is highly de-
pendent on the type of training method employed. "We certainly
found this in our work when we looked at industrial inspection. We
varied training. We used passive, traditional kinds of industrial
approaches. We varied that with active, self-discovery feedback,
and we found that this approach was superior. In fact, if people
OCR for page 35
35
were provided with that kind of training, they could successfully
learn to perform those tasks.
Czaja cautioned, however, that as people are being trained
they are also forming attitudes about having to learn a new skill.
"We did not find any age differences in attitude. We did find,
however, that after training, people who reported a negative ex-
perience in the training session and who felt that they did poorly
had a significant change in attitudes and were not too keen on
using [the new skiing.
MODIFYING Tom: WORKPLACE
In indoor office and factory workplaces the major limitation
on visual functioning of older workers results from a relative lack
of illumination of the unage on the retina. As Fozard reported
to conferees, one study measured the time required by women in
two age ranges from (1~27 years and 4~57 years) to complete a
visual search task under three levels of illumination, 53S, 1,076 and
1,614 Jux. Performance times decreased with increasing levels of
illumination in both age groups but more so for the older women.
Other findings were that both groups expressed a preference for
higher levels of illumination, and the older but not the younger
women experienced greater eye comfort at the two higher levels.
Adequate iBum~nation includes the ability to manipulate the
lighting arrangement both to properly illuminate the object of
visual attention and to control for glare. To achieve this it is
necessary to provide workers with a degree of control over both
general—usually ceiling illumination as well as local illurn~na-
tion usually lamps~f smaller areas. Provision of this degree of
control is necessary but may not be sufficient, inasmuch as most
people are accustomed to thinking of lighting in terms of a fixed
entity, such as ceiling fixture or a piece of furniture, that should
not be moved around simply for functional convenience. For these
reasons the opportunity to manipulate lighting sources should be
supplemented with some training designed to show people how to
manipulate the visual environment to their advantage.
Environmental intervention can also mitigate the effects of
age differences in adapting to changes in illumination. Changes
that require shifts between very different levels of illumination
can be especially difficult for older people. In raising light levels,
however, it is important to avoid glare problems caused by creating
OCR for page 36
36
excessive differences In brightness. One way to achieve this is to
provide workers with individual control over both general and local
iBurn~nation levels.
Video Replay terminal present special problems for the vision
of older workers. With care, special glasses can be worn to brig
the video screen to clearest focus for an individual, but commonly
the keyboard and reference documents are located at other dis-
tances. So the individual working at a video display workstation
must either accept blurred vision or change posture in order to
view the keyboard or the reference documents. Thoughtful work-
place design or the use of trifocab or progressive focal lenses can
reduce these problems.
Working-~mtance problems are not just associated with video
displays. Inspection of large diagrams or drawings, reference to
large notice boards, and a multitude of various construction and
manipulative tasks often require critical vision over a range of dif-
ferent viewing distances. Such tasks often present serious difficul-
ties to older bifocal wearers who must change their head position or
posture when they change their viewing from one object distance
to another. Some of these problems are intrinsically unavoidable,
but in many cases specially designed spectacle lenses or redesign
of the work task can make work more comfortable and efficient.
Kosnik pointed out that dimly lit environments may differen-
tially impair the performance of older workers. And older workers'
performance will be doubly compromised if small-s~zed print, me-
ters, label, scales, charts, etc., have to be read in poor or darn
illumination. Older workers may have more difficulty reading or
locating targets when the visual scene Is cluttered with other
objects. As a result, visual acuity, assessed with one target at a
tune or assessed with widely separated targets—may not provide
an accurate guide to the functional acuity that the older worker
brings to the job.
Pastalan offered a number of specific suggestions for enhancing
the safety of older workers through appropriate environmental
design. These include the use of sign systems that employ high
contrast between symbol and background; the introduction of
textured surfaces to reduce glare; the use of redundant cueing
around machines and hazardous areas; the use of extreme contrasts
in transitional zones (e.g., indoor-outdoor entrances); and the use
of red-yellow colors where accents are required. Clearly, there is
OCR for page 37
37
no shortage of ideas for changes that can be made in the workplace
to facilitate the work of people with visual deficits.
JOB REDESIGN
Despite its demands, paid work is a critical component of
adult life, and finding ways of extending a work attachment for the
visually impaired as well as for other workers ~ very ~rnportant.
As Kahne pointed out, "Not only is it the customary source of
economic support for individuals add their dependents, for many
persons it makes possible valuable pension benefits and offers the
only source of health insurance protection at reasonable cost prior
to age 65. It often provides, as well, psychological support of
'community' and a sense of self-identity."
Can part-time work ever be a viable alternative to meet the
needs of older workers for whom vision problems significantly im-
pede the performance of their tasks? There is a lack of information
to answer that question, but Kahne observed that institutional
change to extend work attachment for the visually impaired will
not be easy. Nonetheless, part-time employment may well be one
of the more desirable approaches to responding to the employment
needs of older workers whose declining vision has become a serious
impediment to their employability.
Representative terms from entire chapter:
visual field
