Digital eye strain: prevalence and associated factors among information technology professionals, Egypt

Abstract

Digital eye strain (DES) is a growing occupational and public health problem and one of the most frequent reasons for seeking medical care. The objectives of this study are to identify the prevalence and to study some associated personal, ergonomic, and environmental factors of DES among information technology (IT) professionals at Tanta University, Egypt. An interview questionnaire was used to collect data related to socio-demographic, job, ergonomic and environmental characteristics. Computer vision syndrome questionnaire (CVS-Q) was used for the assessment of DES. It was used to measure ocular and visual symptoms related to computer use. CVS-Q includes 16 symptoms that are scored using two rating scales, one for frequency and the other for intensity. A total of 108 IT professionals were included. Prevalence of DES was 82.41%. The most common symptoms were headache (81.5%), burning of the eye (75.9%), and blurred vision (70.4%). Significant predictors of DES were female gender (OR = 2.845), age ≥ 35 years (OR = 1.112), daily computer use more than 6 h (OR = 1.351), duration of work more than 10 years (OR = 1.793), wearing corrective glasses (OR = 5.009), distance from the monitor less than 20 in. (OR = 4.389), not using antiglare screen (OR = 0.214), no brightness adjustment of screen (OR = 0.015), not taking break time during computer work (OR = 0.007), exposure to air pollution (OR = 5.667), use of the air conditioner (OR = 23.021), and exposure to windy environments (OR = 3.588). Prevalence of DES was found to be high among IT professionals. Significant predictors of DES were female gender, older age, wearing eyeglasses, long duration of computer use, unadjusted ergonomic workstation, and dry environment. DES is a problem that can be prevented by increasing knowledge and awareness about DES by providing computer users with eye health education, periodic training on a proper ergonomic computer workstation, and adjustment of the suitable comfortable workplace environment.

Full text

RESEARCH ARTICLE
Digital eye strain: prevalence and associated factors
among information technology professionals, Egypt
Hanaa Abdelaziz Mohamed Zayed
1
&Shimaa M. Saied
2
&Eman Ali Younis
2
&Salwa A. Atlam
2
Received: 24 September 2020 /Accepted: 8 January 2021
#The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature 2021
Abstract
Digital eye strain (DES) is a growing occupational and public health problem and one of the most frequent reasons for seeking
medical care. The objectives of this study are to identify the prevalence and to study some associated personal, ergonomic, and
environmental factors of DES among information technology (IT) professionals at Tanta University, Egypt. An interview
questionnaire was used to collect data related to socio-demographic, job, ergonomic and environmental characteristics.
Computer vision syndrome questionnaire (CVS-Q) was used for the assessment of DES. It was used to measure ocular and
visual symptoms related to computer use. CVS-Q includes 16 symptoms that are scored using two rating scales, one for
frequency and the other for intensity. A total of 108 IT professionals were included. Prevalence of DES was 82.41%. The most
common symptoms were headache (81.5%), burning of the eye (75.9%), and blurred vision (70.4%). Significant predictors of
DES were female gender (OR = 2.845), age ≥35 years (OR = 1.112), daily computer use more than 6 h (OR = 1.351), duration of
work more than 10 years (OR = 1.793), wearing corrective glasses (OR = 5.009), distance from the monitor less than 20 in.
(OR = 4.389), not using antiglare screen (OR = 0.214), no brightness adjustment of screen (OR = 0.015), not taking break time
during computer work (OR = 0.007), exposure to air pollution (OR = 5.667), use of the air conditioner (OR = 23.021), and
exposure to windy environments (OR = 3.588). Prevalence of DES was found to be high among IT professionals. Significant
predictors of DES were female gender, older age, wearing eyeglasses, long duration of computer use, unadjusted ergonomic
workstation, and dry environment. DES is a problem that can be prevented by increasing knowledge and awareness about DES
by providing computer users with eye health education, periodic training on a proper ergonomic computer workstation, and
adjustment of the suitable comfortable workplace environment.
Keywords Digital eye strain .Information technology professionals .Weather
Introduction
The expressions digital eye strain (DES) and computer vision
syndrome (CVS) are used interchangeably. One of the major
consequences of the digital revolution is the increase in the use
of electronic devices. Despite their advantages, the use of
computers and other visual display terminals (VDTs) for a
prolonged time may have harmful effects on vision, leading
to a greater risk of computer vision syndrome (CVS) or digital
eye strain among their users (Artime Ríos et al. 2019).
Computer vision syndrome is defined as a “series of ocular
and visual symptoms which are caused by using the comput-
er,”and these problems are progressive and can cause signif-
icant and frequent discomfort for computer users. Nearly 60
million people suffer from CVS globally with a million new
cases occurring each year (Sen and Richardson 2007). The
discomfort associated with this disorder results in an increased
error rate and reduced job satisfaction and work productivity.
The problem has become a workplace concern among com-
puter users especially in those occupationally exposed
(Izquierdo et al. 2007;Rosenfield2011; Tesfa et al. 2019).
It is reported that more than 75% of daily activities of all
occupations need to use the computer since 2000 (Blehm et al.
2005). Visual-related complaints are the most commonly
Responsible Editor: Lotfi Aleya
*Hanaa Abdelaziz Mohamed Zayed
hanazayed55@yahoo.com
1
Department of Occupational Health and Industrial Medicine, Faculty
of Medicine, Tanta University, Tanta, Egypt
2
Department of Public Health and Community Medicine, Faculty of
Medicine, Tanta University, Tanta, Egypt
Environmental Science and Pollution Research
https://doi.org/10.1007/s11356-021-12454-3

stated health problems occurring among the majority of com-
puter workers (Charpe and Kaushik 2009).
Eyestrain, blurred vision, headache, and dry eyes are the
most common complaints associated with DES (Lee et al.
2020). Eye strain is characterized by two groups of symptoms:
external symptoms including burning, tearing, irritation, and
dryness and internal symptoms such as strain, ache, and head-
ache behind the eyes that are associated with accommodative
stress (Sheedy et al. 2003).
Researchers in their studies reported the prevalence ofDES
among video display terminal (VDT) workers was about 80%
as compared to 23% for musculoskeletal disorders (Zakai
et al. 2017). Another study found that the prevalence of DES
ranged from 64 to 90% among computer workers (Hayes et al.
2007). In Egypt, a study reported that the prevalence of DES
among bank workers was 85.2% (Kamal and El-Mageed
2018).
Working practices, workplace environment, and worksta-
tion ergonomic design are important determinants of DES
symptoms among computer users. Ergonomic studies recom-
mended office ergonomic and medical interventions in addi-
tion to computer operators training on office ergonomic to
improve visual health and productivity in computer-related
occupations (Amick et al. 2012).
Environmental factors like smoke, air pollution, air condi-
tioning, and windy environments were reported to be related
to manifestations of DES (Sharma 2011;Leetal.2014).
Information technology workers spend their workday in front
of computer screens. In India, a study reported 7 from each 10
information technology (IT) workers had symptoms of DES
(Bansal et al. 2013).
Few published studies have been performed to explore
DES among Egyptian computer users; thus, the present study
was conducted to determine the prevalence and associated
factors contributing to DES among IT professionals at a large
University in Egypt.
Participants and methods
Study design
It is a cross-sectional study.
Time and sitting of the study
This study was performed during a period of 6 months from
the first of April to the end of September 2020 at information
technology units in the 14 colleges affiliated to Tanta
University. Each college has an information technology unit.
Tanta University is an Egyptian University located in Tanta
City in Gharbia Governorate. Tanta city is the capital of
Gharbia Governorate and is located between Cairo and
Alexandria, 94 km north of Cairo and 130 km southeast of
Alexandria. Tanta University includes 14 colleges in addition
to one Technical Nursing Institute as follows: Medicine,
Dentistry, Pharmacy, Science, Commerce, Law, Arts,
Engineering, Education, Agriculture, Nursing, Specific
Education, Physical Education, and Computing and
Information.
Study population
All computer workers (n= 126) who were in service during
the study period, used the computer for at least 1 year, and
working on the computer for at least 3 h/day were included.
Employees who had ocular problems before employment or
due to another cause such as accidents or a previous operation,
systemic disease such as collagen vascular disease or endo-
crine disease (thyroid disease), and age more than 50 years
were excluded.
Sample size
The sample size was calculated by utilizing the Epi Info soft-
ware developed by CDC, Atlanta, Georgia, USA (Epi Info™
7.2.2.6). The estimated prevalence of DES among IT profes-
sionals was 70% (Arumugam et al. 2014) with a margin of
error of 5% and 95% confidence limit and a design effect of 1
with an increase by 20% of nonresponse rate; the required
sample size was estimated as 110 persons. After the applica-
tion of exclusion criteria and discarding the incomplete ques-
tionnaires, the effective number of eligible participants was
108 IT professionals.
The study was approved by Tanta Faculty of Medicine
Research Ethics Committee (REC) and informed consent
was obtained from all participants.
Data collection
Each participant completed two questionnaires: the anamnesis
and history of exposure questionnaire and the computer vision
syndrome questionnaire (CVS-Q).
1. Anamnesis and history of exposure questionnaire was
developed by the researchers and included the following
parts:
(b) Basic data related to demographic profile and job char-
acteristics such as the duration in the present job, hours
of computer use per day, previous occupations, and fre-
quency of breaks during working on computers, work-
days, and rest days in a week. Wearing eyeglasses or
contact lenses.
(c) Questions to assess some ergonomic factors related to a
computer workstation and included distance of eyes from
Environ Sci Pollut Res

the monitor, level of the top of the screen in relation to the
eyes, presence of glare, use of an antiglare screen, bright-
ness adjustment, and taking breaks during computer use.
(d) Questions to assess the association between ocular symp-
toms and environmental workplace weather such as the
use of air conditioning, air pollution, and exposure to
windy environments including an indoor situation (a re-
volving fan) or outdoor in a windy environment and low
humid environment. The validity of the questionnaire
was checked by five experts of occupational health and
industrial medicine, who reviewed the questionnaire for
clarity, relevance, comprehensiveness, understanding,
and applicability. Reliability was estimated (after a pilot
study to test the questionnaire) by αCronbach’stestand
its result was equal to 0.82.
2. Computer vision syndrome questionnaire (CVS-Q) was
used for the assessment of DES.
A reliable and valid questionnaire was designed and vali-
dated by Seguí et al. (2015), and it was adopted and used to
measure perceived ocular and visual symptoms during or im-
mediately following computer work.
The questionnaire includes 16 symptoms that are scored
using two rating scales, one for frequency and the other for
intensity. The responses to the two rating scales for each
symptom were combined multiplicatively into one rating scale
for the analysis, resulting in a single symptom severity score.
The questionnaire has 16 symptoms which include burning,
itching, feeling of a foreign body earing, excessive blinking,
eye redness, eye pain, heavy eyelids, dryness, blurred vision,
double vision, difficulty focusing for near vision, increased
sensitivity to light, colored halos around objects, feeling that
eyesight is worsening, and headache.
To measure the frequency of occurrence, that was, how
often the symptom was presented, a rating scale of 0–3points
was used, with the following categories: never = 0, occasion-
ally = 1 (sporadic episodes or once a week), often = 2 (two or
three times a week), and very often or always = 3 (almost
every day). The three levels of intensity of the symptom were
categorized similarly, on a scale of 1–3 points, where moder-
ate = 1, intense = 2, and very intense = 3. The total score of the
questionnaire was calculated by the following expression:
Score = ∑(frequency of symptom occurrence) ×(intensity
of symptom)
If the total score was more than or equal to 6 points, the
worker is considered to suffer from DES.
Data management
The collected data were analyzed using SPSS 25.0 software
(IBM Corp. Released in 2017. IBM SPSS Statistics for
Windows, Armonk, NY). Descriptive variables were
presented as mean ± SD, frequency, and percentages. The
chi-squared test was used to test for the association between
categorical variables. Student’sttest was used to compare
means. Logistic regression analysis was done to detect the
independent predictors of DES. Adjusted odds ratios and their
95% CI were calculated.
The adopted significance level was Pvalue ≤0.05.
Results
A total of 108 information technology professionals were en-
rolled in this study. Their mean age was 32.2 ± 5.97 years and
a mean duration of computer use was 7.2 ± 3.6 years for a
mean of 7.2 ± 2.8 h per day. Most of the studied participants
were females (63%) and the majority of them had a university
education and above 94.4%. Approximately one-third
Table 1 Socio-demographic and work characteristics of studied
computer workers
Characteristics Study participants n=108
n%
Gender
Male 40 37.0
Female 68 63.0
Residence
Urban 79 73.1
Rural 29 26.9
Age groups (years)
<35 62 57.4
≥35 46 42.6
Mean ± SD 32.2± 5.97
Educational level
Secondary and technical 6 5.6
Bachelor’s degree and above 102 94.4
Wearing corrective glasses
Yes 35 32.4
No 73 67.6
Wearing contact lenses
Yes 5 4.6
No 103 95.4
Duration of computer use (years)
<10 72 66.7
≥10 36 33.3
Mean ± SD 7.2±3.6 years
Duration of daily computer use (hours)
< 6 36 33.3
≥67266.7
Mean ± SD 7.2 ± 2.8 h
Environ Sci Pollut Res

(32.3%) have worn corrective eye glasses and 5 workers
(4.6%) have used contact lenses (Table 1).
The most commonly reported symptoms of digital eye
strain were headache (81.5%), followed by burning of eye
(75.9%), blurred vision (70.4%), feeling that sight is worsen-
ing (70.4%), eye pain (63.9%), and eye redness (56.5%)
Fig. 1.
According to the scoring scale of CVS-Q used in this study,
out of the total 108 studied computer workers, 89 (82.41%)
had DES with a mean of total score which was 15.4 ± 8.7
compared with a mean of 3.3 ± 1.4 for workers without
DES. Significant associations were found between DES and
female gender (P=0.038), age (P= 0.036), duration of daily
computer use (P= 0.002), duration of lifetime computer use
(P< 0. 000), and wearing glasses (P=0.025)Table2.
Ergonomic computer workstation characteristics were re-
corded to have significant associations with DES; distance
from the monitor (P= 0.003), use of antiglare screen (P=
0.004), brightness adjustment (P< 0.000), and taking breaks
during computer use (P<0.000)Table3.
A significant relationship in a form of aggravation of DES
symptoms was found regarding exposure to environmental air
pollution (P= 0.012), use of air conditioning (P< 0. 001),
exposure to windy environments including an indoor situation
(a revolving fan) or outdoor in a windy environment (P=
0.015), and low humid environment (P<0. 001)Table3.
Logistic regression analysis showed that the significant in-
dependent predictors of DES among IT professionals were
female gender (OR = 2.845), age ≥35 years (OR = 1.112),
daily computer use more than 6 h (OR = 1.351), duration of
work more than 10 years (OR = 1.793), wearing corrective
glasses (OR = 5.009), distance from the monitor less than
20 in. (OR = 4.389), not using antiglare screen (OR = 0.214),
no brightness adjustment of screen (OR = 0.015), not taking
break time during computer work (OR = 0.007), exposure to
air pollution (OR = 5.667), use of the air conditioner (OR =
23.021), and exposure to windy environments (OR = 3.588)
Table 4.
Discussion
In this study, the prevalence of DES among studied IT
workers was 82.41%. Our result was similar to that reported
among computer-using bank employees at Minia City, Egypt
(85.2%) (Kamal and El-Mageed 2018). However, the preva-
lence reported in our study was higher than that reported by
Rafeeq et al. (2020) (69.7%) and Artime Ríos et al. (2019)
(56.9%).
Ranasinghe et al. used different diagnostic criteria for DES
and reported a prevalence of 67.4% among computer office
workers in a developing country (Ranasinghe et al. 2016).
They defined the presence of any one of the ocular symptoms,
either intermittently or continuously for at least 1 week during
the previous year as the presence of DES. This may be sub-
jected to the recall bias of the participants. However, we used
the frequency and severity of 16 symptoms in every partici-
pant for the assessment of DES.
A higher prevalence of DES (97.4%) among IT profes-
sionals was reported by Raja et al. (2015). Other studies re-
ported 73% prevalence of DES among computer-using bank
workers (Assefa et al. 2017) and 73.9% among data
75.9
57.4
31.5
50
45.4
56.5
63.9
44.4 47.2
70.4
36.1
30.6
61.1
30.6
70.4
81.5
0
10
20
30
40
50
60
70
80
90
100
Percent
Symptoms of DES
Fig. 1 Distribution of ocular and visual symptoms among study participants
Environ Sci Pollut Res

processors and secretaries (Alemayehu et al. 2014). In India, a
study found that the prevalence of visual complaints was
46.3% among computer operators (Bhanderi et al. 2008).
Another study that was carried out on bank workers found
that the prevalence of ocular symptoms was 31.9% (Mocci
et al. 2001). Various prevalence rates of DES could be ex-
plained by differences in the characteristics of the samples,
methodologies, and the instruments used for data collection.
The current study reported a mean age of 32.2± 5.97 years
among studied workers which was in agreement with other
studies (Davari et al. 2017; Brindha et al. 2015)thatreported
means of ages of 30.2± 7.15 and 29 ± 7.6 among computer
users and information technology professionals, respectively;
increasing use of computers by younger age groups could
explain this low mean of age.
Our study revealed that DES was more prevalent among
workers aged ≥35 years with a significant association (P=
0.036). This result was in agreement with Uchino et al. (2013)
who reported age more than 30 years as a risk factor for DES.
The present study found a significant association of DES
with female gender (P= 0.038), which was in agreement with
Toomingas et al. (2014) and Uchino et al. (2013), who report-
ed a higher frequency of computer-related eye strain among
females than males.
This study showed that the most frequent ocular symptoms
were headache (81.5%), burning of the eye (75.9%), blurred
vision (70.4%), feeling that sight is worsening (70.4%), eye
pain (63.9%), and eye redness (56. 5%). This finding was very
similar to that reported by Rafeeq et al. (2020); they showed
headache (95.2%), blurred vision (84.3%), dryness (68.7%),
heavy eyelid (68.7%), eye redness (66.3%), and eye pain
(63.9%) as the most prevalent symptoms.
Also in line with our results, eye strain (97.8%) and head-
ache (82.1%) were the most common ocular complaints re-
ported by Bali et al. (2007). Also, our results were in accor-
dance with Shalaby et al. (2018) who reported eye fatigue
(63%), eye burning (45%), blurred vision (34.3%), and red-
ness (27.7%) as the most prevalent visual symptoms among
VDT users. Sen and Richardson (2007) reported headache
(61%) and redness (46%) as the commonest ocular complaints
in their study which was similar to our results.
The current study showed a significant association between
DES and duration of computer use in years (OR = 1.793,
P< 0. 001). This result was in agreement with Kamal and
El-Mageed (2018) who stated that ocular complaints had a
statistically significant positive correlation with the duration
of computer use. Also, other studies stated that the duration of
the computer work was directly related to the eye symptoms
and that a longer duration resulted in persistent complaints that
continued even after computer work was ended (Raja et al.
2015; Logaraj and Madhupriya 2014).
This study found a significant association between ocular
complaints and daily hours of computer use as the prevalence
of DES was higher among workers who use computers for
more than 6 h daily (OR = 1.351, P< 0. 014). This finding
was in agreement with Raja et al. (2015) who found a higher
prevalence of visual symptoms among workers spending
more than 6 h daily using the computer. Also, in the same line
Table 2 Associated variables
with digital eye strain among
studied computer workers
Variables Workers with DES n=89
(82.41%)
Workers without DES n=19
(17.59%)
OR (95% CI) χ
2
P
n%n%
Gender
Male 29 72.5 11 27.5 0.352 (0.128–0.968) 4.301
0.038*
Female 60 88.2 8 11.7
Age groups (years)
< 35 47 75.8 15 24.2 0.298 (0.092–0.970 4.375
0.036*
≥35 42 91.3 4 8.7
Duration of daily computer use (hours)
< 6 24 66.7 12 33.3 0.215 (0.076–0.611) 9.229
0.002*
≥6 65 90.3 7 9.7
Duration of lifetime computer use (years)
< 10 53 73.6 19 26.4 0.736 (0.641–0.845) 11.528
0.000*
≥10 36 100.0 0 0.0
Wearing corrective glasses
Yes 33 94.3 2 5.7 5.009 (1.088–23.063) 5.039
0.025*
No 56 76.7 17 23.3
DES digital eye strain; *statistically significant
Environ Sci Pollut Res

with our results, Kamal and El-Mageed (2018)showedthat
the prevalence of eye complaints was significantly higher
among workers who use the computer more than 4 h per day.
The current study showed a significant relation between
DES and wearing eyeglasses (OR = 5.009, P= 0.039). This
result was in line with Assefa et al. (2017) and Reddy et al.
(2013) who found that computer workers who wore eye-
glasses were significantly more probable to suffer DES com-
pared with those not wearing.
Distance from the monitor is an important factor for the
occurrence of eyestrain. When the screen is closer to the eyes,
the eyes have to do extra work to accommodate, leading to
overworking of the ciliary muscles of the eye and inducing the
symptoms of DES as eye fatigue and headache. Also, concen-
tration on the screen decreases the frequency of blinking and
exposes the eye to the air current, leading to redness, burning,
tiredness, and eyestrain (Taptagaporn et al. 1995).
This study showed that there was a significant association
(OR = 4.389, P= 0.005) of DES among workers who main-
tain < 20 in. distance from the computer. This result was in
agreement with previous studies which found a significant
association of ocular complaints among workers who did
not maintain the suitable distance of 20–24 in. from the screen
and DES (Taptagaporn et al. 1995; Kamal and El-Mageed
2018), while another study showed that the ocular complaints
were less frequent among workers maintaining viewing dis-
tance more than 12 in. (30 cm) and that it was the highest
when the viewing distance was less than 30 cm (12 in.), which
was statistically significant (Bhanderi et al. 2008), while a
previous study recommended a viewing distance of 50–
70 cm (Agarwal and Sharma 2013).
This study showed that there is a statistically signifi-
cant relation between DES and taking breaks from com-
puter use as ocular symptoms were more prevalent among
Table 3 Association between
ergonomic and environmental
variables with digital eye strain
among studied computer workers
Variables Workers with DES Workers without DES OR 95% CI χ
2
P
89 (82.41) 19 (17.59)
Distance from the monitor (inches)
< 20 64 90.1 7 9.9 4.389 1.55–12.422 8.55
0.003*
≥20 25 67.6 12 32.4
Level of the top of the screen
Above the eye level 13 100.0 0.0 27.3 ––3.242
0.233
At the eye level 65 79.3 17 20.7
Below the eye level 11 84.6 2 15.4
Use of antiglare screen
Yes 12 60.0 8 40.0 0.214 0.072 -0.641 8.501
0.004*
No 77 87.5 11 12.5
Brightness adjustment
Yes 10 37.0 17 63.0 0.015 0.003–0.074 51.115
0.001*
No 79 97.5 2 2.5
Taking break (minutes)
Yes 69 94.5 15 42.9 0.077 0.023–0.259 22.798
0.000*
No 20 57.1 4 5.5
Are your ocular symptoms get worse by exposure to air pollution?
Yes 85 85.0 15 15.0 5.667 1.276–25.16 6.26
0.012*
No 4 50.0 4 50.0
Are your ocular symptoms get worse by the use of air conditioning?
Yes 56 97.0 2 3.0 23.021 4.944–107.183 25.98
0.001*
No 24 58.5 17 41.5
Are your ocular symptoms get worse by exposure to windy environments?
Yes 74 87.1 11 12.9 0.279 0.096–0.810 5.96
0.015*
No 15 65.2 8 34.8
Are your ocular symptoms get worse by exposure to a low humid environment?
Yes 77 100.0 0 0.0 2.583 1.659 -4.023 57.27
0.001*
No 12 38.7 19 17. 6
*Statistically significant. OR odds ratio, CI confidence interval
Environ Sci Pollut Res

workers who did not take frequent breaks. Similar find-
ings were shown by other researchers who reported that
burning of the eyes and eyestrain were found to be sig-
nificantly associated with the workers who did not take
breaks during computer use (Agarwal and Sharma 2013).
Also, our results are supported by other authors (Kamal
and El-Mageed 2018;Fenety and Walker 2002)whofound
that taking frequent breaks during using the computer in-
creases the efficiency and relaxes the accommodative
system with the consequent reliving of eye strain. Also,
Assefa et al. (2017) reported that working on the comput-
er for more than 20 min without break was about 2 times
more probable to suffer from DES as compared to those
taking a break within 20 min.
Table 4 Results of binary logistic
regression of DES among studied
computer workers
Factors Coefficient SE POR 95% CI
Upper bound–lower bound
Gender
Male (Ref)#
Female
1.046 0.517 0.043* 2.845 1.033–7.833
Age
<35(Ref)
≥35
0.106 0.052 0.041* 1.112 1.005–1.231
Duration of daily computer use (hours)
<6(Ref)
≥6
0.301 0.122 0.014* 1.351 1.063–1.717
Duration of lifetime computer use (years)
<10(Ref)
≥10
0.584 0.150 0.001* 1.793 1.336–2.406
Wearing glasses (years)
Yes
No (Ref)
1.611 0.779 0.039* 5.009 1.088–23.063
Distance from the monitor (inches)
<20
≥20 (Ref)
1.479 0.531 0.005* 4.389 1.550–12.422
Level of the top of the screen
Above the eye level
At the eye level
Below the eye level (Ref)
−0.364–0.816 0.656 0.695 0.141–3.438
Use of an antiglare screen
Yes
No (Ref)
−1.540–0.559 0.006* 0.214 0.072–0.641
Brightness adjustment
Yes
No (Ref)
−4.207–0.819 0.000* 0.015 0.003–0.074
Taking a break
Yes
No (Ref)
−2.560–0.617 0.001* 0.007 0.023–0.259
Exposure to air pollution
Yes
No (Ref)
1.735 0.761 0.023* 5.667 1.276–25.160
Use of air conditioner
Yes
No (Ref)
3.136 0.785 0.000* 23.021 4.944–107.183
Exposure to windy environments
Yes
No (Ref)
1.278 0.544 0.019* 3.588 1.235–10.423
*Statistically significant. SE standard error, OR odds ratio, CI confidence interval
(Ref)# reference category
Environ Sci Pollut Res

The current study revealed that ergonomic computer work-
station regards, use of antiglare screen, and adjustment of
brightness while using the computer were significantly asso-
ciated with a low prevalence of DES (P<0.01). Raja et al.
(2015) supported our results when they stated that risk factors
related to DES were improper workstation setup or inappro-
priate use of workstation, glare, and reflections from the dis-
play and backgrounds.
Environmental factors that have been pointed out as possi-
ble causes of eye symptoms include bad quality of the indoor
air, high room temperature, low relative room humidity, poor
lighting conditions, the presenceof glare, screen brightness, or
improper design of the workstation (Rosenfield 2011; Parihar
et al. 2016).
The current study showed a significant association of ocu-
lar complaints and exposure to air pollution (OR = 5.667, P=
0.023), air conditioning (OR = 23.021, P< 0. 000), windy en-
vironments either indoor as a revolving fan or outdoor to the
windy environment (OR = 3.59, P= 0.019), and low relative
humidity (P< 0. 001). Brindha et al. (2015) confirmed our
results when they reported that windy environment and use
of air conditioning significantly worsen manifestations of
DES. Effects of these environmental factors were explained
by Parihar et al. (2016) as they increase the pre-corneal tear
film evaporation, leading to hyper-osmolarity and aggravating
symptoms of digital eye strain.
Out regression analysis showed that the significant predic-
tors of DES among IT professionals were female gender
(OR = 2.845), age ≥35 years (OR = 1.112), daily computer
use more than 6 h (OR = 1.351), duration of work more than
10 years (OR = 1.793), wearing corrective glasses (OR =
5.009), distance from the monitor less than 20 in. (OR =
4.389), not using antiglare screen (OR = 0.214), no brightness
adjustment of screen (OR = 0.015), not taking break time dur-
ing computer work (OR = 0.007), exposure to air pollution
(OR = 5.667), use of the air conditioner (OR = 23.021), and
exposure to windy environments (OR = 3.588) Table 4.
Our findings were supported by Ranasinghe et al. (2016)
who stated that female gender (OR 1.28), increasing age and
duration of occupation (OR 1.07), and daily computer usage
(OR1.10) were associated with significantly increased risk of
developing DES. Also, Rahman and Sanip (2011), in their
study, reported that spending more than 7 h per day on the
computer at work was a significant predictor for CVS (OR
2.01). Tesfa et al. (2019) stated that factors significantly asso-
ciated with CVS were duration of occupation (AOR = 3.165;
95% CI = 1.16, 8.57), average time spent on computer per day
(AOR = 3.163; 95% CI = 1.52, 6.59), and computer bright-
ness adjustments (AOR = 2.81; 95% CI = 1.22, 6.47).
The limitation of this study was being a cross-sectional
study without comparing by a control group (non-exposed)
which limits the inference of causality and could only demon-
strate the association between DES and identified risk factors.
So prospective follow-up studies among IT professionals
without DES are recommended. Another limitation is that
our study did not include ophthalmic examinations and
depended on the self-reported symptoms only.
Conclusion
Prevalence of DES was found to be relatively high among IT
professionals. The factors associated with its occurrence were
female gender, older age, wearing eyeglasses, long duration of
computer use, unadjusted ergonomic workstation, and dry
environment.
Recommendations
DES is a problem that can be prevented by increasing knowl-
edge and awareness about DES by providing computer users
with eye health education, periodic training on a proper ergo-
nomic computer workstation, and adjustment of suitable com-
fortable environmental workplace weather.
Author’s contributions Hanaa Abdelaziz Zayed: selection of the idea of
the research paper, participated in data collection and statistical analysis
of data, and she was a major contributor in writing and revision of the
manuscript; Shimaa Mohammad Saied: conceptualization of the study,
shared in writing, statistical analysis of data, and editing and revision of
the manuscript. Eman Ali Younis: participated in data collection and
writing of the paper. Salwa Abd Elmagid Atlam: shared in writing and
revision of the manuscript.
Data availability Not available.
Compliance with ethical standards
Conflict of interest The authors declare that they have no conflicts of
interest.
Ethical approval This study was approved by Tanta Faculty of
Medicine Research Ethics Committee (REC).
Informed consent Informed written consent was taken from all study
participants.
Consent to publish Not applicable.
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