OCCUPATIONAL HEALTH PRACTICE IN
COMPUTERS
PRESENTATION BY
DR . P.RAMESH BABU
DY.M.S,BHPL
ERGONOMICS
WHAT IS IT
DEF: “ FITTING THE JOB TO THE WORKER”
WORD Ergonomics – derived from Greeck
ergon
nomos
: work
: Natural laws
Ergonomists study human capabilities in relationship to work demands.
POSTURE
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In recent years, ergonomists have attempted to define postures which
minimize unnecessary static work and reduce the forces acting on the
body. All of us could significantly reduce our risk of injury if we could
adhere to the following ergonomic principles:
All work activities should permit the worker to adopt several different,
but equally healthy and safe postures
Where muscular force has to be exerted it should be done by the largest
appropriate muscle groups available.
Work activities should be performed with the joints at about mid-point
of their range of movement. This applies particularly to the head, trunk,
and upper limbs.
THE PROBLEM

Here, however, we arrive at a serious problem - and a challenge to
conventional ergonomic thinking: In order to put these
recommendations into practice, a person would have to be a skilled
observer of his or her own joint and muscle functioning and would have
to be able to change his or her posture to a healthier one at will. No one
develops this sort of highly refined sensory awareness without special
training. Therefore, in order to derive the benefits of ergonomic
research, we must learn how to observe our bodies in a new way.* Any
attempt to improve workplace conditions can have only limited success
if this issue is ignored.
A SOLUTION

One training program that cultivates precisely these skills is the
Alexander Technique. It has a long history of helping people develop the
subtle coordination of thought and physical action required to monitor
and alter harmful patterns of posture and movement. In short, it
enables its students to put ergonomic principles into practice, and thus
helps them reduce their risk of developing a repetitive strain injury.
Ergonomics:
Training in ergonomics involves;
 Designing of machines.
 Tools
 Equipment
 Manufacturing process.
 Lay out of the places of work.
 Methods of work.
 Environment
in order to achieve greater efficiency of both
man & machine.
Objective of Ergonomics
“ to achieve the best mutual adjustment
of man and his work, for the
improvement of human efficiency and
well being”
uses of computer
What
not
COMPUTERS
Working for hours on end with a computer is now a fact of life.
simple 7 point checklist will help you recognize and avoid the most
common problems:
C ontact stress
O rganisation
M onotony
P osture
U ncomfortable environment
T etchiness
E xercise
Role of a DOCTOR
“ Occupational health should aim at
 Promotion & Maintenance of highest degree of
Physical
Mental
Social well – being of
workers of all occupations
 Prevention among workers of departures from health caused by their
working conditions.
 Protection of workers in their employment from risks resulting from
factors adverse to health
 Placing & Maintenance of the worker in an occupational environment
adopted to his physiological & psychological equipment
SUMMARY: “ THE ADOPTATION OF WORK TO MAN & EACH MAN TO HIS
JOB”
OCCUPATIONAL HEALTH
LEVELS OF APPLICATION:
 Health promotion.
 Specific protection.
 Early Diagnosis.
 Treatment.
 Disability limitation
 Rehabilitation
TOOLS:
• Epidemological approach
•Statistics
•Health screening
•Health education
ERGONOMICS-COMPUTERS
Computers are, of course, here to stay:.
Ergonomic considerations,
eg furniture, heights, angles, etc. have a bearing and
it is important to get these easily adjustable
external elements correctly organised.
Rather than looking at the problem from the outside, in terms of "good
chairs", the "right position", or the "correct way to lift", what about
considering the more fundamental internal aspects of how we organise
our balance and co-ordination? These are the things which influence
how comfortable we stay, how tired we get, how alert or mentally
"sharp" we are and how prone to injury or stress we become. They are
also the elements over which we can learn to have a direct and instant
personal control.
QUESTIONS ASKED
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correct type of chair, stool, desk, or table to be used in order to prevent
the bad habits which these pieces of furniture are supposed to have
caused
TO AVOD;
basic patterns of good "Use of the Self"; that is, how to optimise
performance and minimise the risk of suffering a range of musculoskeletal injuries
INTRODUCTION to Computers

Computers has become an integral part of life.

We come across it at every stage of life, right from
banking to gaming to education , infact this
presentation is also a gift of computers, but every
good thing comes with a price.

Bad Form Lead To Painful Computing, Ergonomic
Injuries

New studies show that if you don't use the proper
form when working on a computer, there is every
chance of getting discomfort, pain and even injury.

New research shows it takes more than just an
ergonomic desk chair or a split keyboard to
prevent health problems affecting millions of
computer users.

But that doesn't mean computer users should
resign themselves to a life of chronic pain, said Dr.
Erik Peper and Katherine Hughes Gibney of San
Francisco State University's (SFSU) Institute for
Holistic Healing Studies.
INTRO CONTD …
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Much like developing a golf swing or a tennis serve, if you don't use the proper
form when working on a computer, you chance discomfort, pain and even injury.
Therefore the need for people to develop healthy computing habits extends beyond
those working in positions such as data entry, which are normally associated with
repetitive motion injury.
However, Peper and Hughes Gibney resist the common descriptor "repetitive
motion injury," noting that muscle groups are used repetitively all the time without
injury.
Instead, they see repetitive motion as one factor among many that contribute to a
cluster of symptoms they call "computer-related disorder" (CRD).
"Because computer use is pervasive in modern society, by the time people hit the
corporate market, they have unwittingly learned bad computing habits and so they
are already at risk for CRD."Businesses spend millions of dollars teaching
employees how to use software, but they neglect training on how to work on
computers productively while maintaining health.“
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Ergonomics doesn't provide all the answers. You can be working in the 'optimum
ergonomic position' and still be tense."
The problem is "dysponesis" -- inappropriate muscle tension.
HISTORY
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ENIAC, short for Electronic Numerical Integrator And Computer, was the first
all-electronic computer designed to be capable of being reprogrammed by
rewiring to solve a full range of computing problems.
ENIAC was developed and built by the U.S. Army for their Ballistics Research
Laboratory with the purpose of calculating ballistic firing tables. ENIAC was
conceived of and designed by J. Presper Eckert and John William Mauchly of
the University of Pennsylvania. The computer was commissioned on May 17,
1943 as Project PX, constructed at the Moore School of Electrical Engineering
from mid-1944, and formally operational from February 1946 having cost
almost $500,000.
Physically ENIAC was a monster—it contained 17,468 vacuum tubes, 7,200
crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5
million hand-soldered joints. It weighed 30 short tons (27 t), was roughly 2.4 m
by 0.9 m by 30 m, took up 167 m² and consumed 160 kW of power.
These computers itself were a big hazards
Computers have evolved in these decades from this monster to slim gadget like
laptops
FIRST
NOW YOUR GOING TO SEE COMPUTER
ENIAC
ENIAC
Transistors size variation
PROBLEMS
Awkward Postures, which might include: prolonged work with hands
above the head or with the elbows above the shoulders; prolonged work
with the neck bent; squatting, kneeling, or lifting; handling objects with
back bent or twisted; repeated or sustained bending or twisting of
wrists, knees, hips or shoulders; forceful and repeated gripping or
pinching.
Forceful Lifting, Pushing Or Pulling, which might include: handling
heavy objects; moving bulky or slippery objects; assuming awkward
postures while moving objects.
Prolonged Repetitive Motion, which might include: keying; using
tools or knives; packaging, handling, or manipulating objects.
Contact Stress, which might include: repeated contact with hard or
sharp objects, like desk or table edges.
Vibration, which might include: overuse of power hand tools.
Ergonomics and Health Issues
•
Ergonomics Defined
•
Repetitive Stress Injuries
•
Avoiding Repetitive Stress Injuries
•
Eyestrain
•
Electromagnetic Fields
Ergonomics and Health Issues Ergonomics Defined
Ergonomics is the study of the physical relationship
between people and their tools – such as computers.
Extended or improper computer use may result in a
number of ailments, such as:
•
Repetitive injuries
•
Carpal tunnel syndrome
•
Eyestrain
•
Exposure to electromagnetic fields
Ergonomics and Health Issues Repetitive Stress Injuries
• Repetitive stress injuries (RSIs) result from using the
body continuously in ways it was not designed to
work.
• RSIs have appeared in office workers who spend a
lot of time using the computer keyboard and mouse.
• Carpal tunnel syndrome is a common type of
repetitive stress injury, which may be caused by
extended or improper use of a computer keyboard.
Ergonomics and Health Issues Avoiding Repetitive Stress Injuries
•
One of the easiest ways to avoid RSIs is to use
ergonomically correct furniture, including an
ergonomically designed chair and keyboard.
•
An ergonomically correct chair features adjustable
height, lower-back support, and armrests. It should
allow you to type with your forearms parallel to the
floor.
•
An ergonomically correct keyboard is designed to allow
the hands to rest in a natural, comfortable position so
you can type without overreaching or getting fatigued.
Lower back support
Armrests
Adjustable height
Angles place hands
in a natural position
Ergonomics and Health Issues - Eyestrain
•
Many computer users find their vision deteriorating
after a while. This is caused by using the PC too long,
poor positioning, or other factors.
•
To avoid eyestrain, don't stare at the screen too long,
place the monitor from 2 to 2 ½ feet away, avoid glare,
and keep the screen clean.
•
Use a monitor that holds a steady image without
flickering. Look for a dot pitch no greater than .28
mm and a refresh rate of at least 72 Hz.
Ergonomics and Health Issues Electromagnetic Fields
Electromagnetic fields (EMFs) occur during the
generation, transmission, and use of low-frequency
electrical power. Some people are concerned that EMFs
are linked to cancer.
To reduce your risks from EMF exposure:
•
Take frequent breaks away from the computer.
•
Sit at arm's length from the system unit and monitor.
•
Use a flat-panel display (which does not produce
EMFs).
OCCUPATIONAL HAZARDS IN USING COMPUTERS
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Cumulative trauma disorder (CTD), and Repetitive stress injury
(RSI)
Work-related musculo skeletal system disorders (WMSDs)
carpal tunnel syndrome
back pain
Osteoarthritis
tendonitis
tenosynovitis
"pitcher," "golfer" or "tennis" elbow
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Computer Electromagnetic Radiation and Its Health Effects
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COMPUTER VISION SYNDROME
sore and tired eyes,
blurred vision and
eye fatigue after prolonged use of their terminals.
CARPAL TUNNEL SYNDROME
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According to the Bureau of Labor Statistics, “disorders
associated with R.T.D” account for about 60% of all
occupational illnesses. Of all these disorders, carpal
tunnel syndrome is the condition most frequently
reported.
The carpal tunnel receives its name from the 8 bones in
the wrist, called carpals, that form a tunnel like structure.
The tunnel is filled with flexor tendons which control
finger movement. It also provides a pathway for the
MEDIAN NERVE to reach sensory cells in the hand.
Repetitive flexing and extension of the wrist may cause a
thickening of the protective sheaths which surround each
of the tendons.
The swollen tendon sheaths, or tenosynovitis, apply
increased pressure on the median nerve and produce
Carpal Tunnel Syndrome
MOTOR-thenar muscle at the base of the thumb
atrophies, and strength is lost .
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SENSORY- subjective or objective hypoesthesia
coinciding with median nerve distribution, heat and cold
sensation lost .
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Tinel’s Sign (i.e. distal tingling resulting from proximal
nerve percussion);
ANATOMY
Phalen's sign

Test for Carpel Tunnel Syndrome (CTS). Hold the position for one minute; if pain or
numbness and tingling are felt this is highly suggestive of CTS
positive wrist flexion test
CTS ctd..
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Paresthesias, unusual tingling and the sensation of numbness, paralleling the
nerve’s path, are prime complaints.
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Diagnosis :
Clinical
Electromyogram and a nerve conduction study
gives quantitative support for nerve compression.
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Prevention:
modified layouts of work stations
maintain wrist in a more natural position during work
exercise breaks.
CTS :Rx
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Treatment of CTS may involve surgery to release the compression on the median nerve and/or
use of antiinflammatory drugs and hand splinting to reduce tendon swelling in the carpal
tunnel. Such medical interventions have met with mixed success, especially when an affected
person must return to the same working conditions.
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Effective conservative treatment of CTS should include:
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Chiropractic manipulation of the wrist, forearm and hand
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Ice massage (10 to 12 minutes) several times a day
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minimizing any irritating activities
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wrist strengthening exercises
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wrist stretching exercises
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possible use of wrist brace or splint while sleeping
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applying sound ergonomic principles
COMPUTER VISION SYNDROME
Some visual display users have reported
 sore and tired eyes,
 blurred vision and
 eye fatigue after prolonged use of their terminals.
It is natural for some people to experience visual discomfort if
they've been using their eyes intensively over a long period of
time, whether it is working at a display, studying for an exam
or doing close work.
While eye fatigue may be uncomfortable, it is not damaging to
the eye. It also is a temporary condition and goes away with
rest.
Computer Electromagnetic Radiation and Its Health Effects

The safety of users is a primary consideration when VDTs (Vedeo display
terminals)are introduced into the work environment. VDTs are essentially
electrically identical to television sets. Both VDTs and television sets produce
electromagnetic emissions (sometimes called radiation) from CRT (Cathode ray
tube); the phosphor, which is the chemical composition that coats the inside of the
CRT screen; and from associated electronic components.

Although OSHA has no specific standards that apply to computer workstations or
extremely low frequency electric and magnetic field exposure, there are standards
on radiation, noise, and electrical hazards.
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The radiation levels emitted by video displya terminals are below the occpuational
exposure standards. in many cases ,the levels are below the dectection capabality of
survey instrumentation used.considering the radiation measurments, biological
injury thresholds, and occupational exposure standards, the VDT does not present
a radiation hazards to VDT operator.

There is no significant evidence that the occurence of catract, birth defects ,
miscarriages, or skin rashes is related to radiation exposure from VDTs. Thus,
there is no justification for providing additional (RADIATION ) shielding of the
VDT or lead aprons for the operators or for transferring pregnant women to other
jobs to reduce the irradiation exposure.

Millions of people work with computers every day. There is no single “correct” posture or
arrangement of components that will fit everyone. However, there are basic design goals to
consider when setting up a computer workstation or performing computer-related tasks.

Ergonomics is the vital link between safety, quality, and production. The improved
worker performance and well-being generated through ergonomic implementation can help
management meet their goals of quality and corporate excellence.
Creating the Ideal Computer Workstation:
plan to create an ergonomically sound workstation for computer users, including:
Illustrated guidelines on how to adjust your furniture, computer equipment, and work
aids.
Information on how to organize your work area and tasks.
Checklists to evaluate the ergonomics of your current workstation and for use as
specification lists when purchasing new equipment.
This guide seeks to accommodate most, not all, office workers. If you are very small,
very large, or are visually impaired, you may require accommodations different than those
included in this guide. If that is the case, refer to your safety or occupational health office.
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The Work Area
Upright sitting posture
The user's torso and neck are approximately vertical and in-line, the thighs
are approximately horizontal, and the lower legs are vertical.
Standing posture
The user's legs, torso, neck, and head are approximately
in-line and vertical. The user may also elevate one foot on a rest while in this posture.
Declined sitting posture
The user's thighs are inclined with the buttocks higher than the knee and the angle between the
thighs and the torso is greater than 90 degrees. The torso is vertical or slightly reclined and the legs are vertical.
Reclined sitting posture.
The user's torso and neck are straight and recline between 105 and 120 degrees from the thighs.
MONITORS
QUICK TIPS
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Put monitor directly in front
of you and at least 20
inches away.
Place monitor so top line of
screen is at or below eye
level.
Place monitor perpendicular
to window.
Choosing a suitable monitor and placing it in an appropriate
position helps reduce exposure to forceful exertions, awkward
postures, and overhead glare. This helps prevent possible health
effects such as excessive fatigue, eye strain, and neck and back
pain.
MONITORS
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Consider the following issues to help improve your computer
workstation:
Viewing distance
Viewing angle (height and side-to-side)
Viewing time
Viewing clarity
You should choose a monitor and consider its placement in conjunction
with other components of the computer workstation, including the
keyboard, desk, and chair.
MONITORS
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Potential Hazards
Monitors placed too close or too far away may cause you to assume
awkward body positions that can lead to eyestrain.
–
Viewing distances that are too long can cause you to lean forward and
strain to see small text. This can fatigue the eyes and place stress on the
torso because the backrest is no longer providing support.
–
Viewing distances that are too short may cause your eyes to work harder
to focus (convergence problems) and may require you to sit in awkward
postures. For instance, you may tilt your head backward or push your chair
away from the screen, causing you to type with outstretched arms.
Monitors
Sit at a comfortable distance from the monitor where
you can easily read all text with your head and torso in
an upright posture and your back supported by your
chair.
Generally, the preferred viewing distance is between
20 and 40 inches (50 and 100 cm) from the eye to the
front surface of the computer screen.
Note: text size may need to be increased for smaller
monitors.
Put monitor directly in front of you and at least 20 inches away.
Place monitor so top line of screen is at or below eye level.
Place monitor perpendicular to window
Monitors
Provide adequate desk space between the
user and the monitor (table depth). If there
is not enough desk space, consider doing
the following:
Make more room for the back of the
monitor by pulling the desk away from the
wall or divider; or
Provide a flat-panel display, which is not as
deep as a conventional monitor and requires
less desk space); or
Move back and install an adjustable
keyboard tray to create a deeper working
surface.
Flat-panel displays take up less room
than conventional monitors
Monitors
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Potential Hazard
Working with your head and neck
turned to the side for a prolonged
period loads neck muscles
unevenly and increases fatigue
and pain
Position your computer monitor
directly in front of you so your head,
neck and torso face forward
when viewing the screen. Monitors
should not be farther than 35 degrees
to the left or right
If you work primarily
from printed material,
place the monitor slightly
to the side and keep the
printed material directly
in front. Keep printed
material and monitors as
close as possible to each
other.
Monitors
Display screen is too high
Potential Hazard
A display screen that is too high or low will cause
you to work with your head, neck, shoulders, and
even your back in awkward postures. When the
monitor is too high, for example, you have to work
with your head and neck tilted back. Working in
these awkward postures for a prolonged period
fatigues the muscles that support the head.
Possible Solutions
Comfortable viewing angle
The top of the monitor should be at or slightly below eye level. The
center of the computer monitor should normally be located 15 to 20
degrees below horizontal eye level .
The entire visual area of the display screen should be located so the
downward viewing angle is never greater than 60 degrees when you
are in any of the four reference postures. In the reclining posture
the straight forward line of sight will not be parallel with the floor,
which may increase the downward viewing angle. Using very large
monitors also may increase the angle.
Remove some or all of the equipment (CPU, surge protector, etc.)
on which the monitor may be placed. Generally, placing the
monitor on top of the CPU will raise it too high for all but the
tallest users.
Elevate your line of site by raising your chair. Be sure that you have
adequate space for your thighs under the desk and that your feet are
supported.
Monitors
Stresses because of bifocal lenses Bifocal users typically
view the monitor through the bottom portion of their
lenses.
This causes them to tilt the head backward to see a
monitor that may otherwise
be appropriately placed. As with a monitor that is too
high, this can fatigue muscles that support the head.
Lower the monitor (below recommendations for non-bifocal users) so you
can maintain appropriate neck postures. You may need to tilt the monitor
screen up toward you.
Raise the chair height until you can view the monitor without tilting your
head back. You may have to raise the keyboard and use a foot rest.
Use a pair of single-vision lenses with a focal length designed for computer
work. This will eliminate the need to look through the bottom portion of the
lens.
VIEWING CAPACITY
Potential Hazard
Monitors that are tilted significantly either
toward or away from the operator may distort
objects on the screen, making them difficult to
read. Also, when the monitor is tilted back,
overhead lights may create glare on the screen.
This can result in eyestrain and sitting in
awkward postures to avoid eye glare.
Possible Solutions
Tilt the monitor so it is perpendicular to your line of sight, usually by tilting the
screen no more than 10 to 20 degrees. This is most easily done if the monitor has
a riser/swivel stand. A temporary solution involves tilting the monitor back
slightly by placing a book under the front edge. Note: Tilting the monitor back
may create glare on the screen from ceiling lighting and a glare screen may be
needed.
Monitor support surfaces should allow the user to modify viewing distances and
tilt and rotation angles.
Monitors
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Rest your eyes periodically by focusing on objects that are farther away (for
example, a clock on a wall 20 feet away).
Stop, look away, and blink at regular intervals to moisten the eyes.
Alternate duties with other non-computer tasks such as filing, phone work, or
customer interaction to provide periods of rest for the eyes
Factors that reduce image quality make viewing more difficult and may lead to eye
strain. These factors include
– electromagnetic fields caused by other electrical equipment located near
computer workstations, which can result in display quality distortions; and
– dust accumulation, which is accelerated by magnetic fields associated with
computer monitors and can reduce contrast and degrade viewing conditions.
Computer workstations should be isolated from other equipment that may have
electrostatic potentials in excess of +/- 500 volts.
Computer monitors should be periodically cleaned and dusted.
Computer maintenance is required
Keyboards
Put the keyboard directly in front of you.
Your shoulders should be relaxed and your
elbows close to your body.
Your wrists should be straight and in-line with
your forearms
Keyboards
Keyboard Placement - Height

Adjust the chair height and work surface height to maintain a neutral
body posture. Elbows should be about the same height as the keyboard
and hang comfortably to the side of the body. Shoulders should be
relaxed, and wrists should not bend up or down or to either side during
keyboard use.

Remove central pencil drawers from traditional desks if you can't raise
your chair high enough because of contact between the drawer and the
top of the thighs. The work surface should generally be no more than 2
inches thick.
Keyboards
A keyboard tray (may be needed if the work surface or chair
cannot be properly adjusted. The keyboard tray should
Be adjustable in height and tilt,
Provide adequate leg and foot clearance, and
Have adequate space for multiple input devices (for
example, a keyboard and pointer/mouse).
Keyboards
Side view illustration showing the
recommended range for keyboard
placement
Keyboards
Keyboard that is too far away
Keyboard that is too close
Possible Solutions
Place the keyboard directly in front of you at a distance that allows your elbows to stay
close to your body with your forearms approximately parallel with the floor.
A keyboard tray may be useful if you have limited desk space or if your
chair has armrests that interfere with adequate positioning
Keyboards
Upward bending of the wrist
Side bending of the wrist
Tented and raised keyboard design
Split keyboard design
Keyboards
Alternative keyboards allow the user to place the keypad
and mouse on either side of the keyboard.
Pointer/Mouse
Pointing devices such as a mouse
now come in many sizes, shapes,
and configurations. In addition to
the conventional mouse, there are
trackballs, touch pads, finger tip
joysticks, and pucks, to name a few.
Selection and placement of a
pointer/mouse is an important
factor in creating a safe computer
workstation.
Keep the pointer/mouse close to the keyboard.
Alternate hands with which you operate the pointer/mouse.
Use keyboard short cuts to reduce extended use
Pointer/Mouse
Mouse placement that is too far away and not
in the same plane as the keyboard
Appropriate mouse placement
Pointer/Mouse
Keyboard with a built-in touchpad
Sensitivity and speed (how fast the pointer
moves on the screen when the pointing device
is moved by the hand) should feel
comfortable and be adjustable. The pointer
should be able to cover the full screen while
the wrist is maintained in a straight, neutral
posture.
Sensitivity should be set so you can control
the pointing device with a light touch. Most
current devices have sensitivity settings that
can be adjusted through the computer control
panel.
Avoid tightly gripping the mouse or pointing
device to maintain control.
A trackball's exposed surface area should be
at least 100 degrees (Figure 9). It should feel
comfortable and rotate in all directions to
generate any combination of movement.
Pointer/Mouse

Fingertip joystick for a
notebook computer
Pointer/Mouse
Trackball device in laptop
Pointer/Mouse
Mouse wrist rest
Use a mouse pad with a wrist/palm rest to promote neutral
wrist posture
Substitute keystrokes for mousing tasks, such as Ctrl+S to save,
and Ctrl+P to print.
Other Input Devices
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Touch pads allow you to move the cursor on the
computer
screen by simply gliding your finger across a
small pad. Unlike mouses, trackballs, and other
pointing devices, touch pads
have no moving parts to clog or break, so they
never require disassembly for cleaning.
Touch screens allow you to point directly at an
object. They require little or no training, are
faster than other pointing devices, and require
no extra work surface. However, the
disadvantages of touch screens include arm
fatigue, smudges, optical interference, and
increased glare.
Voice input allows you to “talk” to your
computer. Currently, programs can understand
and respond to natural speech
delivered at rates of up to 160 words per
minute.
Other Input Devices
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Pen-like devices enter and manipulate information through
contact with the computer screen or a horizontal pad through
pressure, light, electromagnetic disruption, or radio frequencies.
A pen pad requires about as much room on the work surface as a
mouse. If pen technology is used on a horizontal pad, a
workstation must provide adequate nonglare lighting for both it
and the computer screen.
A gesture glove is worn on your hand and responds to hand and
arm motions.
glove is most useful for high-tech applications, such as
sophisticated engineering projects, where it might be used to turn
the page in a 3-D landscape.
Handwriting recognition programs are available but they are
still primitive, witherror rates of up to 10%.
MOBILE COMPUTING
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General Mobile Computing Rules of the Road
When using your notebook computer in your work or home office, you
may be more comfortable using a standard keyboard and display along
with comfortable furniture.
Use a chair that gives you good lower back support. In a mobile
computing environment, consider propping a pillow, rolled-up towel or
other soft object against the back of your chair. Sitting on a soft object
such as a cushion is an easy way to adjust an otherwise non-adjustable
chair such as those typically found in a kitchen or hotel room.
Keep your forearms, wrists and hands in a relaxed, neutral position.
This can be accomplished by adjusting the height of either the work
surface or your chair.
Keep your thighs parallel to the floor and your feet flat on the floor or a
footrest. In a mobile computing environment, consider placing your feet
on a book, briefcase or other solid object.
MOBILE COMPUTING
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Keep your head in a comfortable position. A 15-degree downward viewing angle is
optimal.
Maintain a comfortable viewing distance. 20 to 30 inches is optimal

Position your display so as to avoid glare or reflections from overhead lighting,
outside sources of light, or even reflections off of your own shirt. Consider closing
blinds, turning off some overhead lights and/or orienting the display perpendicular
to the light source.

Keep your display screen clean and set the contrast and brightness to levels that
allow you to see the screen clearly. Remember that LCD displays are not as bright
as standard displays.

Frequent short work/rest breaks are especially important in a mobile computing
environment. In addition, it is especially important to listen to your body and take a
work/rest break when the first signs and symptoms of discomfort arise. You may
also want to try some basic stretching exercises.
Never operate your notebook computer while trying to drive.
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Wrist/Palm Supports
Use a wrist rest to maintain straight wrist postures and to minimize
contact stress during typing and mousing tasks
Wrist/palm rests encourage neutral
wrist postures
Document Holders
Documents should be at the same height and distance as the monitor.
Document Holders
Example of in-line
document holder
Desks
Desk surface should allow you to place the monitor
directly in front of you, at least 20 inches away.
Avoid storing items, such as a CPU, under desks.
Desks
Poor mouse and keyboard placement
because of desktop clutter
Potential Hazards
Limited space on the work surface may cause users to place
components and devices in undesirable positions. This
placement may lead to awkward postures as you reach for a
pointer/mouse or look at a monitor that is placed to the side.
Possible Solutions
Work surface depth should allow you to:
View the monitor at a distance of at least 20 inches (50 cm), and
Position the monitor to achieve the appropriate viewing angle,
which is generally directly in front of you.
The location of frequently-used devices (keyboard, phone, and
mouse) should remain within the repetitive access (primary work
zone)
Recommended zones for workplace components
Potential Hazard
Some desks and computer equipment
have hard, angled leading edges that
come in contact with a user's arm or wrist
This can create contact stress, affecting
nerves and blood vessels, possibly
causing tingling and sore fingers.
Possible Solutions
To minimize contact stress,
Pad table edges with inexpensive materials such as pipe insulation,
Use a wrist rest, and
Buy furniture with rounded desktop edges.
Footrest
Potential Hazard
Desk surfaces that are too high or too
low may lead to awkward postures,
such as extended arms to reach the
keyboard, and raised shoulders.
Possible Solutions
Raise work surfaces by inserting stable risers such as boards or concrete
blocks under the desk legs if necessary.
Remove center drawers of conventional desks to create additional thigh
clearance if necessary.
Lower work surfaces by cutting off desk legs if necessary. If the work
surface cannot be lowered, raise the chair to accommodate the user. If
needed, provide a footrest to support the user's feet Provide height-adjustable
desks. Clearance for the legs, under the desktop, should generally be
between 20-28 inches (50-72 cm) high
Areas Under the Desk or Work Surface
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Potential Hazard
Inadequate clearance under the work surface
may result in discomfort and performance
inefficiencies, such as the following:
– Shoulder, back, and neck pain due to users
sitting too far away from computer
components, causing them to reach to
perform computer tasks; and
– Generalized fatigue, circulation restrictions,
and contact stress due to constriction of
movement and inability to frequently
change postures.
Possible Solutions
Provide, to the extent possible, adequate
clearance space for users to frequently change
working postures (see recommended
dimensions). This space should remain free of
items such as files, CPUs, books, and storage .
Be sure clearance spaces under all working
surfaces accommodates at least two of the
three seated reference working postures, one
of which must be the upright seated posture.
Chairs
The backrest should conform to
the natural curvature of your
spine, and provide adequate
lumbar support.
The seat should be comfortable
and allow your feet to rest flat on
the floor or footrest.
Armrests, if provided, should be
soft, allow your shoulders to relax
and your elbows to stay close to
your body.
The following parts of the chair are important elements to consider in creating a
safe and productive workstation:
Backrest
Seat
Armrest
Base
You should adjust your chair along with appropriately placing your monitor,
keyboard, and desk.
Chairs
Adjustable chair
and backrest
Natural S-curvature of the spine
Seat pan with a rounded,
"waterfall" edge
Shoulders in various positions
Office chair with adjustable armrests
Telephones

Use a speaker phone or head
set for long conversations.
Awkward posture during telephone use
Conventional headset
Breaks required frequently
micro breaks or rest pauses
Workstation Environment
Arrange your office to
minimize glare from overhead
lights, desk lamps, and
windows.
Maintain appropriate air
circulation. Avoid sitting
directly under air conditioning
vents that "dump" air right on
top of you.
Lighting
Blinds are on the windows and
the monitor
is placed at an angle (perpendicular)
Bright light entering from a window
Glare
Glare from overhead light source
Monitor with a glare screen
Light: Generally, a large number of low powered lamps
rather than a small number of high powered
Ventilation
Air circulation
Air ventilation diffuser
Exposure to chemicals, volatile organic compounds (VOCs), ozone, and particles
from computers and their peripherals
(for example, laser printers) may cause discomfort or health problems
Possible Solutions
Enquire about the potential for a computer or its components to emit pollutants.
Those that do should be placed in well-ventilated areas.
Maintain proper ventilation to ensure that there is an adequate supply of fresh air.
Allow new equipment to "air out" in a well-ventilated area prior to installing.
Ergonomic Tips for Computer Users
Ergonomics:
Study of how people physically
interact with their work – fitting
the job, the equipment and the
work environment to the worker.
Office of Horrors
Ideal Office
Additional Setup Steps
• Eliminate any reflection on your monitor.
• Position any additional equipment in
accessible places.
Exercises for the office
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One of the biggest injury risk factors is static posture.
Try to spend at least 5 minutes every hour away from your computer.
Remember to ONLY stretch to the point of mild tension.
Try to incorporate the stretches into your daily routine.
This slide provides some illustrations of simple active stretches to perform at the
office.
Hand Exercises

Tightly clench your hand into a fist and release, fanning out the fingers. Repeat
3 times
Back and Shoulder Exercises

Stand up straight, place your right hand on your left shoulder and move
your head back gently. Do the same thing for the right shoulder
Head and Neck Exercises
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Move head sideways from left to right and back to left
Move head backwards and then forward
Computer and Desk Stretches …

Sitting at a computer for long periods often cause neck and shoulder
stiffness and occasionally lower back pain. Do these stretches every
hour or so throughout the day or whenever you feel still. Also be sure to
get up and walk around the office whenever you think of it. You’ll feel
better.
… Computer and Desk Stretches …
… Computer and Desk Stretches
THANK YOU
Data taken from NIOSH, CDC, OSHA, ILO,DOD -AMERICA.