Prolonged Computer Use
Health complaints associated with prolonged computer use as perceived
by computer users
Lamiaa Amin Awad , Lecturer
Community Health Nursing Dept, Faculty of Nursing, Mansoura University
Sahar Mohamed Soliman, Lecturer
Community Health Nursing Dept, Faculty of Nursing, Mansoura University
Amel Ibrahim Ahmed , Lecturer
Community Health Nursing Dept, Faculty of Nursing, Mansoura University
Computers have become ubiquitous in the office work place and their use is growing. They have
many advantages for inventory management, record management, electronic communication and office
automation. Computerized jobs are more sedentary; require more cognitive processing, mental attention
and less physical expenditure of energy. Many jobs that require heavy daily computer use have been
found to be stressful. The length of working in front of video display units (VDT) may be a direct cause
of reported health complaints among computer users. This study is conducted to relate the duration of
exposure to health effects resulting from computer use. The present study was carried out in different
computer workstations at Alexandria and Mansoura cities. These work stations were chosen from
technical schools and private computer offices. The study included 600 computer users (271 from
technical schools and 329 from private computer offices). A structured questionnaire sheet was
developed and used to assess the personal data of participants, appropriateness of workstation
environment, and ergonomic criteria of computer station in addition to health complaints of the studied
computer users. The results indicate that the majority of the studied population complained of
musculoskeletal and eye discomforts
Introduction
concluded that visual system discomfort is a
common problem when working with VDTs and
there was no evidence of damage or permanent
impairment to the visual system, but it only
appears in the form of visual fatigue, headache
and blurring of vision (6). A study of NIOSH
indicated that; 75% of VDT users complained of
occasional aching or burning eyes at work,
followed by blurred vision, also it was found that
up to 90% of computer uses report visual
problems and eye irritation (7).
Other health complaints are musculoskeletal
problems reported in 22% of computer users; these
problems appear in the form of low back pain,
hand pain and stiffness in the neck and shoulders.
Moreover; muscle tightness and tenderness occur
due to repetitive movement, support of the head
in a fixed posture to look at the screen and holding
the arms over the keyboard for prolonged periods,
also it may be due to poor ergonomics of
workstation (7-12). Musculoskeletal problems
occurring with computer use may range from
simple muscle fatigue or neck and back ache to
cumulative trauma disorders; which are
associated with tasks that require repetitive
motions occurring over long periods of time. A
study conducted on 21 patients who suffered from
Today, almost every one interacts with
computers on a daily basis for several reasons
such as creating ideas, producing documents,
retrieving information and corresponding with
friends. Along with the expanding use of this
technology adverse health changes for computer
users was reported. An increased number of
computer workstations in the work place have
resulted in health concerns related to vision and
body aches and pains. Problems associated with
computer workstations are generally temporary
and can often be solved using simple corrective
measures (1). Many studies in several developed
countries have reported that visual display
terminal (VDT) has adverse health effects on
visual system, musculoskeletal system; also causes
stress
related
disorder,
skin
disorder,
photosensitive epilepsy, and adverse pregnancy
outcome. Visual symptoms that may be
experienced by computer operators are visual
fatigue, blurred or double vision, burning and
tearing eyes, headaches and frequent changes in
eyeglass prescription (2-4). The American
Optometric Association AOA reports that over 10
million patients a year schedule eye exams due to
computer-related vision problems. WHO (2001)(5)
ASNJ. Vol.5, No. 1, 2006
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Prolonged Computer Use
neuropathy revealed that 86% of them reported
aggravating factors of computer use during the
months prior to the onset of symptoms, these
factors are high work intensity, overwork and
exceeding work duration causing an unusual
strain (13). Also, one study conducted in 1998 on
382 high school students indicated that 4% had
been diagnosed with carpal tunnel syndrome as a
result of computer use (14).
Regular computer use is associated with an
increase in skin irritation most probably due to
high level of dust particles that are attracted to the
skin by a build-up of static electricity caused by
the screen (15). Moreover, job stress manifested in
VDT operators in the form of irritability and
depression (16).
not complete the questionnaire form, while 65
students complained from computer related
symptoms before using computer, these were
excluded from the study. The total number of
students enrolled in the study was 271 students.
2- A number of 400 questionnaire sheet was
distributed throughout the randomly selected
eight private computer offices, out of them 329
computer users were included in the study. The
rest were excluded from the study: 118 did not
complete the questionnaire and 51 not conforming
the study criteria.
The total number of the study participants
was 600 computer users.
Criteria of the target population
1- Age up to ≤ 45 years
2- Computer work duration ≥ one year
3- Free from computer related symptoms
before working in computer field;
these symptoms are musculoskeletal
complaints (backache, hand pain hand
numbness, neck pain, and leg pain),
visual complain and eye irritation
symptoms, headache or irritability.
Tool:
A structured questionnaire form was
developed by the researchers. It consisted of 31
closed ended questions and 5 open ended
questions. It was used to assess the following:
1- Personal characteristics of the participants
such as age, gender and level of education
2- Data of using computer such as, reasons
and duration of using computer
3Appropriateness
of
workstation
environment such as room temperature, light,
ventilation, presence of air draft and noise.
4- Ergonomic criteria of computer station
such as, seat, key board, mouse and monitor
criteria to be described as comfortable or not as
perceived by participants. In addition to questions
that describe the size and shape of mouse and
distance of the monitor from user.
5- Health complaints of the studied computer
users as perceived by them. A list of computer
related symptoms namely; musculoskeletal
complaints (backache, hand pain hand numbness,
neck pain, and leg pain), visual complain and eye
irritation symptoms, headache or irritability to be
checked, according to its presence before or after
using computer.
Aim of the study:
To identify health complaints associated with
prolonged computer use as perceived by
computer users.
Materials and methods:
Study design:
The study was a cross- sectional survey to
investigate the effect of prolonged computer using
on human health.
Settings:
The present study was carried out in twelve
computer workstations at Alexandria and
Mansoura cities. These work stations were chosen
from four technical schools and eight private
computer offices.
The technical schools were chosen by using
multistage sampling technique as follows: Two
districts were chosen randomly from each city
(middle and eastern districts in Alexandria and
western and eastern districts in Mansoura) A list
of nine technical schools having computer
branches in the four selected districts were
obtained. Out of them technical schools that have
computer branch were selected (five schools in
Alexandria and four schools in Mansoura). From
these technical schools two were selected
randomly in each city (one school from each
district).
The eight private computer offices were
chosen by simple random technique (five located
in the middle and eastern districts of Alexandria
and three from western and eastern districts of
Mansoura).
Subjects:
1- All students studying computer science
enrolled in the second and third year in the
selected four technical schools were included in
the study (500 students). Of these 94 students
refused to participate in the study, 70 students did
ASNJ. Vol.5, No. 1, 2006
Method:
1-Administrative process:
a- Informal visit to the schools and
workstations was done by the researchers to
introduce the study and obtain their
cooperation.
66
Prolonged Computer Use
b- Oral approval was obtained from
schools managers and workstations directors.
c- Oral approval was obtained from
participants to be included in the study.
2-Development of the study tool:
a- The researchers developed the
questionnaire form after reviewing of recent
literatures then the content validity was tested
by experts in that field.
b- A pilot study was carried out on 20
computer users. These were chosen randomly
from other computer workstation to ensure
the clarity of the questionnaire.
3-Data collection:
a- Data collection was conducted
during the period from October 2004 to March
2005 through the interview of participants
during visits to work stations on two days per
week to explain the aim of the work, the
meaning of questions and the method of
questionnaire filling. Each visit consumed
approximately 1.30 to 3 hours.
b- Data was scanned to exclude
individuals who do not fulfill the stated
criteria of the target population.
Statistical analysis
SPSS package (version 0.9) was used for the
statistical analysis of the obtained data. Kendall'stau- b test was used to estimate the correlation
between prolongation of computer usage and the
occurrence of health complaints.
Generally, the majority of computer
workstations
have
a
comfortable
work
environment as perceived by the studied
population regarding temperature, ventilation,
light and quietness. As regards to ergonomic
features more than two thirds have a appropriate
seat height and seat base while 51.5% have a
suitable seat back. Almost one quadrant of them
have arm and/ or foot rest in their workstations.
Also nearly half of the studied computer users
have appropriate angle of key board to elbow and
key board fixers. Three quadrants use curvedsmall mouse and appropriate monitor distance
(around 75cm) and monitor level in relation to
vision span, also most of monitors are clear and
have comfortable brightness table (3).
Table (4) shows that the most prevailed health
complaints
among
computer
users
are
musculoskeletal complaints (neck pain in 48.5%,
backache in 47.3%, hand pain in 43.7%, hand
numbness in 27% and leg pain in 27%) and visual
complaints (blurring of vision in 50.8%, eye
fatigue in 46.7%, eye tearing 37.8%, eye redness
26.2% and eye itching 22.3%). Moreover; 24.7%
and 11.5% of the studied population complain of
headache and irritability respectively. All of these
complaints started after at least one year of using
computer.
Table (5) describes the frequency of health
complaints in relation to their onset. Eye
complaints and musculoskeletal complaints have
the highest frequency within the first and second
years of using computer (3.2% and 14.5% of eye
complaints, especially eye fatigue, blurring of
vision and eye irritation in the form of tearing and
itching.) and (2.8% and 12.5% of musculoskeletal
complaints especially hand pain and neck pain)
respectively. While Psycho- sensory complaints
(headache and irritability) obviously appeared
within the second and third year of using
computer.
Table (6) illustrates that duration of work and
daily working hours have a positive significant
correlation with the most of health complaints. All
eye complaints are significantly correlated with
duration of work except eye tearing which is
insignificantly correlated with this factor. Also,
eye complaints are significantly correlated with
daily working hours except deterioration of vision
is insignificantly correlated with this factor. While
all musculoskeletal complaints which are
significantly correlated with both duration of
work and daily working hours except leg pain and
hand numbness showed insignificant correlation.
In addition irritability is significantly correlated
with duration of work and daily working hours.
Results
It's apparent from demographic characteristics
of computer users in table (1) that the ages of the
computer users included in the study ranged from
13 up to 45 years and distributed in three age
groups. The first group ≤18 constitute 48.3% of the
studied population with a mean age of 16.8± 1.3
years, the second group aged from >18 to less than
30 years and they present 29.4% of the studied
population with a mean age of 23.1± 3.3 years, and
the third group aged >30 years to include 22.3% of
studied population with mean age of 36.6± 1.3.
The overall mean age is 23.1±8.1 years, more than
half of them are males.
Concerning computer using pattern; the mean
duration of work is 4.9 ±3.6 years and the mean
daily working hours is 3.7±2.8 hours. All of the
participants reported that they don’t get a rest
period during working hours. About 45% of the
studied population is studying computer science
followed by 35 % working in computer field as
programmers or typist, and the rest of the studied
population is using computer for retrieving
information or entertainments table (2).
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Prolonged Computer Use
All of the studied population neither take
break nor make physical exercise during work.
Discussion:
The computer's role as an essential office and
home technological resource has developed faster
than has general public understanding of potential
health problems from poor body alignment and
effects of long hours in front of a keyboard and
screen. Moreover, since these conditions typically
do not cause acute pain or other immediate
warning signs, many people are slow to connect
their initial discomfort to their computer use and
associated poor ergonomics (17).
This study revealed that 70% of the studied
population suffered
from
musculoskeletal
discomfort namely, neck pain, hand pain and
backache. These results are in agreement with
other studies that reported a high prevalence of
musculoskeletal discomfort among computer
users in the form of neck pain, backache and hand
pain (18-21). This musculoskeletal complaints; may
be due to poor ergonomic environment that may
lead to cumulative trauma, unhealthy posture,
fixed position for extended period of time and/ or
lacking for performing simple physical exercise to
improve blood circulation.
Computer vision syndrome is the number one
cause of eye strain in the computer work station.
Working at the computer is visually demanding, it
requires excessive ocular motility, continuous eye
focusing and alignment demands (22- 23). Problems
occur when these demands exceed the visual
ability of an individual. Studies conducted in
Egypt (2000) (3), Australia (2000) (24) and Italy
(1999)(25) found that eye discomfort was associated
with computer use, mainly eye strain,
deterioration of vision, aching or burning eyes and
blurred vision. All of mentioned results agreed
with the present study that revealed several eye
complaints that are eye fatigue, blurring of vision,
redness of eye, itching eye and deterioration in
vision that lead to changing eye glass. Also the
revealed headache and irritability among the
studied population were reported by other
researchers as a result of using computer (1, 26).
These complaints may be due to the emission of
chemical vapors and hotness from computers that
contain a lot of plastics, and/ or prolonged
focusing on computer screen.
Extensive and prolonged use of computers at
the work place and at home today, has given rise
to a range of computer related health complaints.
There are three broad categories of health
problems, visual, musculoskeletal, and mental
stress. The reasons for these problems are
repetitive activities such as data entry and using
ASNJ. Vol.5, No. 1, 2006
the keyboard, prolonged periods looking at the
monitor,
working
with
intense
mental
concentration, or alternatively, long periods of
monotonous tasks (27).
The more the hours users spent in front of a
computer screen the higher the incidence of
computer syndrome. Gerr and Monteilh C 2004 (28)
reported an association between health outcomes
and daily hours of computer use. The present
study indicated a significant effect of work
duration on eye discomfort, musculoskeletal
discomfort and irritability either with duration of
working years or duration of working daily hours.
This result was similar to Al-Wehedy et al. (1999)
(21) and Jensen 2004 (29) who found that the
duration of computer use predicate a high
prevalence of musculoskeletal disorders and
headache that increase significantly with
increasing the working years and daily working
hours. Jackson et al 1997 (30) revealed that
prolonged exposure to computer screen may lead
to visual and general work related symptoms
twice as frequently as those who spent less time
working computer screen. Shimai et al 1986 (31)
and Nakazawa et al 2002 (32) reported a positive
correlation
between
musculoskeletal,
eye
discomfort and length of computer service. The
length of daily working hours is considered as a
risk factor for the development of musculoskeletal
complaints among computer users (33). In addition,
Rechichi et al 1996 (34) found that the main factor
determining visual fatigue in VDT operators is the
amount of time spent. Also, Travers and Stanton
2002 (35) found that visual disturbance
manifestation appeared to increase as duration of
video display terminals (VDT) increased.
Many studies recommended that individual
should have recovery time ranged from 10 to 15
minutes each hour during computer work. Also
regular stretch break ranged from 30 o 60 second
every half hour is needed to improve blood
circulation and decrease the level of discomfort
that is associated with sitting in one position (29, 36).
Conclusion
The study indicated that the prevalence of
general disorders among computer users increase
significantly with the duration of computer use
and the number of working hours, also complaints
started after at least one year of using computer
and increased by time.
Recommendations
So it is recommended to perform a periodical
medical checkup for early detection of sign and
symptoms related to computer use, take at least
ten minutes break each work hour and perform
simple exercise during working time.
68
Prolonged Computer Use
Table I: Distribution of the studied population according to personal characteristics
Item
Number
600
Percentage%
Mean of
ages (X±S.D)
Personal data
Age in years
<18-
290
48.3
16.8±1.3
18-
176
29.4
23.1± 3.3
30+
134
22.3
36.6± 1.3
Overall mean of ages
23.1± 8.1
(X±S.D)
Gender
Male
328
54.7
Female
272
45.3
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Prolonged Computer Use
Table II: Distribution of the studied population according to features of computer using
Number
Item
600
Percentage%
Number of years in using computer
>5-
371
61.8
5-
136
22.7
10+
93
15.5
X±S.D
4.9±3.6
Number of daily working hours in using computer
>5-
436
72.7
5-
124
20.7
10+
40
6.7
X±S.D
3.7±2.8
Reasons of using computer
Studying computer sciences
271
45.2
Working in computer field
210
35
Entertainment
67
11.1
Retrieving information
52
8.7
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Table III: Distribution of computer workstation according to physical environment criteria
as described by the studied population
Number
Item
600
Percentage%
Workstation environment
Suitable temperature
480
80
Suitable ventilation
449
74.8
Suitable light
420
70
Quiet room
378
63
Appropriate seat height
417
69.5
Comfort seat base
402
67
Comfort seat back
309
51.5
Presence of foot rest
145
24.2
Presence of arm rest
133
22.2
Presence of key board fixer
299
49.8
Appropriate angle of key board to elbow
259
43.2
Curved
513
85.5
Straight
87
14.5
Small
431
71.8
Large
169
28.2
Appropriate distance from user
447
74.5
Appropriate to vision level
378
63
Comfort brightness
488
81.3
Comfort clearance
468
78
Ergonomic appropriateness
Seat criteria
Key board criteria
Mouse criteria
Shape
Size
Monitor criteria
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Table IV: Distribution of health complaints among the studied population
Number
Item
600
Percentage%
Musculoskeletal complaints
Neck pain
291
48.5
Hand numbness
284
47.3
Hand pain
262
43.7
Legs pain
162
27
Backache
141
47.3
Blurring of vision
305
50.8
Eye fatigue
280
46.7
Eye tearing
227
37.8
Eye redness
157
26.2
Eye itching
134
22.3
Deterioration of vision
96
16
Headache
148
24.7
Irritability
69
11.5
Eye complaints
Psycho- sensory complaints
Person may be presented by more than complaints
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Prolonged Computer Use
Table V: Distribution of health complaints according to their onset of occurrence
Occurrence
Occurrence
Complaints
within the second
within the first year
year
Occurrence
within the third year
Number
Percentage%
Number
Percentage%
Number
Percentage%
Number=
14
3.2
63
14.5
358
82.3
Eye tearing
11
2.5
27
6.2
189
43.4
Eye fatigue
10
2.3
43
9.8
227
52.2
Blurring of vision
7
1.6
43
9.8
255
58.6
Eye itching
7
1.6
17
3.9
110
25.3
Eye redness
6
1.4
24
5.5
127
29.2
Eye complaints
435
Deterioration
4
vision
0.91
22
5.1
70
16.1
Musculoskeletal
complaints
12
2.8
52
12.5
356
84.7
Hand pain
10
2.3
34
8
218
51.9
Neck pain
6
1.3
37
8.5
248
59
Hand numbness
5
1.2
28
6.6
137
32.6
Backache
3
0.7
21
5
251
59.7
Leg pain
2
0.5
23
5.5
117
27.8
5
3.1
41
25.3
116
71.6
Headache
5
3.2
32
19.7
111
68.5
Irritability
0.0
0.0
9
5.5
60
38.3
Number=
420
Psychosensory complaints
Number=
162
Person may be presented by more than complaints
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Prolonged Computer Use
Table VI: Correlation between computer work duration and occurrence of
health complaints
Duration of work
Complaints
Daily working hours
r
P
r
P
0.097
0.006
0.246
0.000
0.286
0.000
0.294
0.000
Eye redness
0.282
0.000
0.256
0.000
Eye tearing
0.056
0.114
0.205
0.000
Eye itching
0.068
0.056
0.157
0.000
0.085
0.017
0.019
0.593
Neck pain
0.208
0.000
0.172
0.000
Hand pain
0.138
0.000
0.246
0.000
0.014
0.694
0.062
0.086
Backache
0.228
0.000
0.220
0.000
Leg pain
0.023
0.517
0.007
0.847
Headache
0.069
0.051
0.040
0.268
Irritability
0.229
0.000
0.246
0.000
Eye fatigue
Blurring of
vision
Deterioration
vision
Hand
numbness
P ≤ 0.05
r = correlation coefficient
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Prolonged Computer Use
international scientific conference: Work
with Diplay units. Stokholm, 2003; 17-20.
References
1Kaplan and Sadock's. Anxiety
disorder. In: Synopsis of Psychiatry:
Behavioural sciences and clinical psychiatry.
8th ed. Giza. Mass publishing co: 2001; 583584.
12Al-Wehedy A, Hammad S.M, AlGilany A. Some health hazards among
computer users. Benha Medical Journal,
2000; 16 (3) :601–615.
13Jørgen Riis Jepsen, Upper limb
neuropathy in computer operators? A
clinical case study of 21 patients. BMC
Musculoskelet Disord. 2004; 5: 26.
2World Health organization (WHO).
Update on visual display terminals and
workers' health. Geneva: World Health
Organization, 1999.
14Jones, C.S. and B.Orr. ComputerRelated
Musculoskeletal
Pain
and
Discomfort Among High School Students.
Am. J. Health Stud; 1998; 14: 26.
3Emara
AM.
Health
Hazards
associated with work on video display
terminals A WHO consideration. Egyptian J
Occup Med; 2001; 15 (1): 105 – 108.
15Asia Monitor Resource Center
(AMRC). 1993; Handbook on computer and
health. Quated from Al-Wehedy A,
Hammad S.M, Al-Gilany A. Some hazards
among computer users, Benha Medical
Journal, 1999; 16 (3) :601–615.
4Lim, S.Y, Carayon, P. An integrated
approach to cumulative trauma disorders in
computerized
offices:
the
role
of
psychosocial work factors, psychological
stress, and ergonomic risk factors. In: smith
MJ, Salvendy G, Advances in human
factors/ergonomics, 2001; 19A.
16Smith
M.J,
Cohen
B.GF,
Stammerjohn L.W. An investigation of
health complaints and job stress in video
display operations. Hum Factors, 2001; 23:
387– 400.
5World Health Organization (WHO).
Video Display Units (VDUs) and human
health, Fact Sheet No. 201. 2001;
http://www.who.int/inffs/en/fact201.html
17Guidelines for Office Ergonomics.
Computer and Workstation Equipment,
2006; 6: 6105.
6Computer program (3M). Office
ergonomics,
2000;
www.3m.com/intl/kr/office/pdf/ecrgono
mic_2.pdf
18Lai, K.W. Computer use and
potential health risk. Computers in New
Zealand Schools, 1995; 7 (2): 43-47.
7Sauter S. Predictors of strain in VDT
users and traditional office workers. In:
Grandjean E. Ergonomics and health in
modern offices. London Taylor and Francis;
2001; 129 – 135.
19Frank AL. Effects on health
following occupational exposure to video
display terminals. Lexington: University of
Kentucky. Department of Preventive
Medicine and Environmental Health Report,
2000; 40536: 84.
8Pascarellis E.F, Kella J.J. Soft tissue
injuries related to use of the computer
keyboard: a clinical study of 53 severely
injured persons. J Occup Med; 2001; 3: 522 –
532.
20Solana. Sweden. Work with video
display
units.
National
Board
of
Occupational Safety and Health (NBOSH),
Quoted from WHO (World Health
Organization)
(1987):
Visual Display
Terminals and Worker's Health. WHO Offset
Publication Geneva; 1985; 99.
9Rempel D.M, Harrison R.J, Barnhart
S. Work related cumulative trauma disorders
of the upper extremity. JAMA; 2001; 267: 838
– 842.
10Armstrong T.J, Foulke J.A, Bernard J,
Gerson J, Remple D.M. 2002; Investigation of
applied forces in alphanumeric work. Am Ind
Hyg Assoc; 55:30-35.
21Waheed A, Fouad M, Bassiouni H,
Abdel-Aziz M. Health hazards of visual
display terminals among exposed workers in
Suez Canal cities. Mansoura Med ; 2000; 30
(2): 15-40.
11Ong C.N, Phoon W,O. Influence of
age on VDT work. In: Proceedings of an
22the
ASNJ. Vol.5, No. 1, 2006
1
Croasmun J. Easy on eyes= better on
job. Ergonomic today TM; 2002;
Prolonged Computer Use
31Shimai S, Iwasaki S, Takahashi M,
Narita S, Suzuki H. Survey on subjective
symptoms in VDT workers: complaint rate
and years of service. Sangyo Igaku; 1986; 28
(2): 86- 95.
http://www.ergoweb.com.
23Guetschow J. New ergonomic lines.
Ergonomic
today
TM;
2000;
http://www.ergoweb.com.
24Turner P.J. Visual requirement for
VDT operators. Australian Journal of
Optometry, 2000;65: 58-64.
32Nakazawa T, Okubo Y, Suwazono Y,
Kobayashi E, Komine S, Kato N, Nogawa K.
Association between duration of daily VDT
use and subjective symptoms. Am J Ind
Med; 2002; 42 (5): 421- 6.
25Rubino FG, di Bari A and Turbati M.
Epidemiological analysis of discomfort signs.
Boll Oculist; 1999; 68: 113-123.
26Bongers PM, Winter CR, Kompier
MAJ and Hildebrandt VH. Psychosocial
factors at work and nusculoskeletal diseases:
a review of the literature. Scand J Work
Enrviron Health; 2001; (19) 5:297-312.
27MANOJ DASG,
Movements
International Yoga for computer related
health problems, Manoj Dash; 2005;
http://groups.yahoo.com/group/Yoga.
28Gerr F, Marcus M, Monteilh C.
Epidemiology of musculoskeletal disorders
among computer users: lesson learned from
the role of posture and keyboard use. J
Electromyogr Kinesiol; 2004;14(1):25-31.
33Waersted
M,
Wstgaard
R.H.
Working hours as a risk factor in the
development of musculoskeletal complaints.
Ergonomics, 1991; 34 (3): 265- 76.
34Rechichi C, De Moja C.A, Scullica L.
Psychology of computer use XXXVI. Visual
discomfort and different types of work at
video display terminals. Percept Mot Skills,
1996; 82 (3 Pt 1): 935- 8.
35Travers P.H, Stanton B.A. Office
workers and video display terminals:
physical, psychological and ergonomic
factors. AAOHN J; 2002; 50 (11): 489- 93.
29Jensen C. Development of neck and
hand-wrist symptoms in relation to duration
of computer use at work. Scand J Work
Environ Health; 2003; 29(3):197-205.
36Sheedy J.E. The bottom line on fixing
computer- related vision and eye problems.
Journal of the American Optometric
Association. 1996; 67 (9): 515.
30Jackson A.J, Barnett E.S, Stevens A.B,
McClure M, Patterson C, MeRynolds M.J.
Vision screening, eye examination and risk
assessment of display screen users in a large
regional teaching hospital. Ophthalmic
Physiol Opt; 1997; 17 (3): 187- 95.
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