Eliminating

1

• Eliminating
• Computer
• Eyestrain

2
Contents

• Introduction
• Lighting
• Workstation Configuration
• Vision Optometry

3
Introduction
4
Eyestrain complaints are typically reported by
three of four people who use computers for
extended periods. One researcher has estimated
that each year about 10 million people seek eye
exams for computer-related eyestrain.
5
Trends indicate that people are spending more
time using computers at home and at work.
Additionally, due to baby-boomer demographics,
more age-related eyestrain can be anticipated.
6
There is no evidence to suggest computer use will
damage eyesight. However, as with any type of clo
se work, nearsightedness may develop faster than
it typically would if close work is limited.
Close work can also induce temporary
nearsightedness which could impact tasks such as
driving. Finally, eyestrain can lead to discomfor
t and reduced productivity.
7
People working at computers for extended periods
may experience

• Vision impairment (e.g., temporary blurred
  distance vision)
  
• Headache
• Ocular discomfort such as sore or dry eyes
• Musculoskeletal problems (e.g., neck and back
  pain) induced when poor postures are assumed to
  compensate for visual deficits or poor visual
  ergonomics

8
People often experience vision deficits that
become more pronounced with demanding visual
tasks. Common problems include

• Reduced close focusing related to aging, known as
  presbyopia
  
• Insufficient focusing speed
• Binocular insufficiency (eyes do not track well
  together)
  
• Farsightedness (the ability to focus well on
  distant objects but poorly on close objects)

9
Many people experience eyestrain because they
need glasses but do not have them, or the glasses
they wear were not properly prescribed or fitted.
10
Eyestrain Reduction Tips

• Close your eyes for several seconds (preferably
  when the boss is away)
  
• Relax your focusing and convergence muscles by
  looking at distant objects
  
• Use eye drops, but not those with red-out agents

• Work on non-computer tasks or take a mini-break
  at least every half-hour

11
People who work at computers are likely to
experience dry eyes - for several reasons.
Some people naturally produce little ocular
lubricating fluid. Additionally, contact lenses i
nterfere with the distribution of this
lubricating fluid across the eye surface.
Dry office air and drafts from air supply sources
may also increase eye dryness.
12
Blink rates are another factor leading to
increased eye dryness. Studies have demonstrated
that people tend to blink less when working at a
computer than during other activities.
A conscious effort to blink frequently is
recommended.
Relaxed - 22 per minute
Reading a book - 10 per minute
Reading text on a computer - 7 per minute
13
Lighting
14
When estimating appropriate lighting levels,
consider the task types to be performed at the
computer. Low ambient light levels may be accepta
ble with jobs that are screen-intensive (e.g.,
desktop publishing). On the other hand, data inpu
t tasks will likely be improved with somewhat
higher ambient light levels, especially if the
source document characters are small or are of
low-contrast.
15
In general, computerized offices should have
one-third to one-half of the ambient light found
in traditional paper-based offices.
If your office light fixtures seem too bright,
try removing one or more lamps (note that some
fixtures do not light with a lamp removed).
Contact Custodial Services for assistance.
16
In addition to using less light, the light should
also be uniform to avoid bright light directly
striking the eye or reflecting from the computer
screen.
17
Natural light can aesthetically enhance an
office, but it typically creates poor visual
ergonomics. If bright sunlight enters computerize
d offices, blinds or other light-reducing window
treatments should be installed.
18
Interior designers occasionally specify motorized
view-preserving shades for large windows.
The shade fabric has tiny holes that allow
occupants to see outdoors while significantly
reducing indoor light levels.
19
Computer monitors should be set at right angles
to windows and to long runs of overhead fixtures.
The orientation depicted at right reduces scree
n glare and eliminates bright light directly
striking the eye.
20
Light fixtures of the type depicted at right are
often satisfactory when located above the
computer monitor. However, as the distance from
the monitor increases, this fixture type may
create screen glare or direct glare in the
operators eyes.
21
Parabolic luminaires (fixtures) focus light
downward. This reduces both direct and indirect (
screen) glare creating a visual environment well
suited to computer use.
22
Parabolic luminaires are designed to reduce
horizontal light transmission and thus
eyestrain. A side effect of this lighting design
is that walls are dark and some occupants may
find the space gloomy. To counter this effect, de
signers often add lighting specifically to
brighten the walls.
23
Traditional fluorescent and parabolic luminaires
are considered sources of direct light.
Pendant luminaires (at right) are suspended from
the ceiling with the lamps oriented up. This
lighting is termed indirect since the light is
reflected off the ceiling. From an aesthetic/de
sign standpoint, the ceiling can be a bit bright,
but the resulting uniform light is ideal for
computing.
24
There are several products on the market that
combine direct and indirect light in one
luminaire. The adjacent photo depicts a luminair
e in which a plastic sleeve can be rotated to
create direct or indirect light, allowing
occupant control over the ratio of direct to
indirect light.
25
If reducing light levels and changing monitor
orientation has not sufficiently reduced screen
glare, an anti-glare screen may be warranted.
A quick way to check for screen glare is to sit
at your computer with the monitor off. Glare
problems will become apparent, as depicted at
right.
26
Anti-glare screens can dramatically reduce screen
glare, but they also inherently degrade screen
images (for example, by reducing screen
brightness). Generally, the more expensive units
perform better. You may wish to select anti-glare
screens that have been certified by the American
Optometric Association.
27
Low light levels are best for work at computers,
yet we need relatively high light levels to read
books and papers. To solve this problem, its bes
t to reduce light from overhead sources and add
adjustable task lighting to illuminate paperwork.
The task light should be constructed and oriente
d to avoid screen glare and/or direct light into
the eye.
28
The most common source of fluorescent light
flicker results from bulbs near the end of their
service life. This can be verified by replacing f
lickering bulbs with new ones.
In very rare cases, there can be wiring problems
that induce electrical surges called harmonics
that cause light fluctuation. An electrician can
verify this for you.
29
Visual Arrangement of the Workstation
30
Viewing close objects causes the focusing and
convergence muscles in the eyes to work harder.
Moving your monitor back may reduce eyestrain (a
distance of 20 - 26 is suggested).
Lowering your monitor may also reduce
computer-related eyestrain. Placing your monito
r directly on the desk top is recommended (not on
top of the computer/CPU).
31
To reduce neck strain, its best to orient the
chair, keyboard and monitor in roughly the same
direction, as depicted here.
32
If you reference source documents frequently,
document/monitor orientation may influence
eyestrain symptoms. Documents are best oriented h
orizontally with respect to the monitor.
33
Vertical orientation is nearly as good as
horizontal. Slant boards like the one shown may
also improve posture when document viewing and
marking is required.
34
Oblique (diagonal) orientation is less than
optimal.
35
Laying documents flat on the desktop may lead to
visual and musculo-skeletal strain.
36
Monitor Characteristics
37
Computer users are encouraged to optimize
contrast, brightness and other monitor settings.
38
Computer users are also encouraged to check
display property settings. Refresh rates of 75Hz
or higher are suggested, and users may prefer to
vary the monitor resolution setting.
Ask your computer support staff for details.
39
Black text on a white background promotes
contrast and reduces eyestrain.
Black text on a white background optimizes
contrast and makes a good choice where large
blocks of text are displayed.
Color text and/or color backgrounds reduce
contrast and should be used with discretion.
White or light text on black or dark backgrounds
can lead to increased screen glare.
Color text on color background reduces contrast
and is not recommended for large text blocks.
White or light text on a black or dark background
increases screen glare and can reduce depth of
focus.
40
Computer monitors emit several kinds of
electromagnetic radiation. To date, there is no
evidence that radiation from computers
represents a health hazard. For additional inform
ation, see the National Institute of Occupational
Safety and Health (NIOSH) report at
http//wwwetb.nlm.nih.gov/monograp/ergo/hazards.ht
ml?
41
Large computer monitors have both advantages and
disadvantages. They are great for applications li
ke desktop publishing. The large screen image a
llows reduced mousing and scrolling. This in
turn limits screen image re-targeting.
Potential problems include

• Reduced viewing distance due to larger monitor
  cabinet
  
• Lower screen resolution

Reading speed may increase or decrease depending
on use patterns and visual acuity.
42
Vision Optometry
E L P O M F R E E O T L P Z T L P E F Z O R I
F Y O U C A N R E A D T HI S G O O D F O R Y O
U
43
If you are experiencing computer-related
eyestrain and are considering having your eyes
checked, here are some things to keep in mind

• Your eye care provider should ask for details
  about your work and work environment
  
• If you suffer from computer-related eyestrain,
  have your vision tested at your screen viewing
  distance
  
• Many people have better than 20/20 vision

44
Our vision tends to deteriorate naturally with
age. Below are some age-related vision facts

• Presbyopia (losing the ability to focus the
  eyes), starts at age 10 and is complete by age
  70
  
• Visual acuity declines with age
• The amount of light needed to read increases by 2
  to 3 times between the age of 20 and 60
  
• Glare becomes more troublesome with age

45
If your visual status is such that you are a
candidate for multifocal lenses, consider that

• Reading bifocals are essentially incompatible
  with computer use
  
• One survey has found that 85 of patients who try
  no-line (progressive addition) lenses like them,
  but also found that some patients feel dizzy or
  nauseous when wearing them
• Trifocals are available with a wider intermediate
  segment for computer viewing
  
• Many eyeglass prescription options are available

46
Most experts agree that lens tints serve only a
cosmetic function. If you are concerned about the
color of light in your environment, you can
change computer screen colors and/or the color
of office light bulbs. Anti-reflective coatings w
ill reduce glare on the eyeglass lens, but do not
reduce screen glare.
47
EHS staff are available to perform lighting
surveys and computer eyestrain evaluations for
ISU personnel. Call 294-5359 for details.
Additional information on vision and eye care can
be found at the American Optometric Association
website http//www.aoanet.org/
48
In summary

• Place your computer monitor back and low
• Use bright light for paper, dim light for
  computers
  
• When working with computers and paper materials
  simultaneously, use less overhead light than
  found in traditional offices and add task
  lighting
• If you experience computer-related eyestrain,
  worksite evaluations and comprehensive optometric
  exams are recommended

49

• finis