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 Table of Contents  
Year : 2018  |  Volume : 19  |  Issue : 1  |  Page : 40-45

Pattern of visual display terminals usage and eye effects among primary school children in Egypt

1 Department of Ophthalmology, Faculty of Medicine, Tanta University, Tanta, Egypt
2 Department of Public Health, Faculty of Medicine, Tanta University, Tanta, Egypt

Date of Submission29-Jun-2017
Date of Acceptance09-Oct-2017
Date of Web Publication1-Feb-2018

Correspondence Address:
Rabab M El-Seht
Ophthalmology Department, Faculty of Medicine, Tanta University Hospital, 31527 Tanta
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/DJO.DJO_44_17

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The aim of this study was to evaluate the effect of visual display terminals (VDTs) use among primary school children.
Patients and methods
A school-based prospective observational cross-sectional comparative study was carried out on two groups of primary school children in Egypt, in the period between January and April 2016. History of using VDTs in different patterns was documented together with the associated different eye complaints, whether visual or nonvisual. External eye examination, red reflex, visual acuity, and noncycloplegic refraction were performed.
The current study included 1075 children in grades 3–6 of primary schools. Their age ranged from 9 to 13 years. The usage of different types of VDTs in private school children was highly significant than in governmental ones (P=0.00001). The computer vision syndrome was significantly higher in private school students (P=0.01). However, the detected visual errors had a nonsignificant association with children using VDTs (P=0.25).
There was a high significant association between certain patterns of VDTs usage in primary school children and certain ocular complaints such as headache and eye fatigue. Visual errors could be measured easily in children, with nonsignificant association with VDTs users.

Keywords: asthenopia in visual display terminals users, computer vision syndrome in school children, eye fatigue and visual display terminals, headache and visual display terminals, visual display terminals and visual disorders

How to cite this article:
El-Seht RM, El-Sabagh H. Pattern of visual display terminals usage and eye effects among primary school children in Egypt. Delta J Ophthalmol 2018;19:40-5

How to cite this URL:
El-Seht RM, El-Sabagh H. Pattern of visual display terminals usage and eye effects among primary school children in Egypt. Delta J Ophthalmol [serial online] 2018 [cited 2019 Mar 22];19:40-5. Available from: http://www.djo.eg.net/text.asp?2018/19/1/40/224568

  Introduction Top

The widespread use of visual display terminals (VDTs) among children in early years of life necessitates more studies about the extent of their effects on eyes in school children. In a modern western society, the use of computers for both vocational and nonvocational activities has become widespread [1]. Ocular complaints by computer users have been grouped collectively and were termed computer vision syndrome [2]. Proper identification of these symptoms and causative factors are necessary for the accurate diagnosis and management [3]. It was defined by the American Optometric Association as ‘a complex of eye and vision problems related to activities that had a great stress on near vision’ [4]. Recent studies recorded that there will be a steady global increase in the internet usage from 40.4% to almost 84% among the whole world’s population in the period from 2014 to 2018 [5].

The aim of the current study was to evaluate the effect of VDTs usage pattern and its association with different eye manifestations or basic ophthalmic findings in a large group of primary school children.

  Patients and methods Top

This study was a school-based cross-sectional comparative study. The study complied with the principles of the Declaration of Helsinki and was approved by the Hospital Ethics Committee. A written informed consent was obtained from the caregivers of the children. The study procedures were approved from the Directorate of Education of Gharbia Governorate.

This study was conducted in Tanta City, Gharbia Governorate, in the middle of Delta region, Egypt, from January to April 2016. It included two groups of children: private school children and government ones. The school fee as documented by student affairs controllers of the different schools was 10 000–30 000 Egyptian pounds/year for the private schools compared with 200 Egyptian pounds for the governmental ones.


The sample size was calculated using Epi-Info (Atlanta, Georgia, USA) program of statistics, of Centers for Disease Control and prevention (CDC 24/7; version Based on a level of significance of 95%, 80% power of the study, estimated prevalence of VDTs use of 50%, and error of 5%, the sample size was estimated to be 384. The sample was increased to 550 for each group (1100 students for both groups) to improve the validity of the results and to cover any losses owing to incomplete questionnaire. For each group of school students, 550 children were chosen by a multistage probability sample technique. First, Tanta educational administration was divided into east and west administrations, then the study subjects were chosen by a random selection of one primary school (a cluster) from the east and another one from the west administration, and then eight classes were chosen randomly from each school (two from each grade third, fourth, fifth, and sixth), with average student/class being 40 students. All children in grades 3–6 who completed the study properly were included.

Children with past history of ocular operations, congenital eye diseases, diabetes mellitus, Bitot’s spots of xerosis, children of spring catarrh, and strabismus in nonfixing eyes were excluded from the study. At the end of data collection, only 1075 students (543 of private school and 532 of governmental school) met the inclusion criteria, gave the consent, and completed the examination and questionnaire, with a response rate of 97.72%.

Data collection included the following:

  1. Self-administered semistructured questionnaire with the following items:
    1. Sociodemographic and academic data of the students (age-sex-residence).
    2. Patterns of VDTs use [device(s), place(s), years of use, and daily hours].
    3. Ocular manifestations that could be related to using VDTs (burning sensation, stinging, headache, redness and eye fatigue) or visual impairment.
  2. Ophthalmological examination: measuring the visual acuity in all children in the classroom using Landolt’ C chart and then recorded in a decimal format. Portable tools of examination were used for anterior segment examination using portable slit lamp (Shin-Nippon, India), red reflex examination using direct ophthalmoscopy and measurement of refraction using Plusoptix A12 R (View Technology Company made in Germany), as a photorefractor device ([Figure 1]). This tool is a noninvasive, infrared video recorder linked to a laptop computer with proprietary software for evaluation. This device measures the refractive data. During normal use, the examiner holds an infrared projector/recorder ∼1 m from the patient. The device produces noises to confirm fixation of the patient’s gaze.
    Figure 1: (a) Plusoptix A12R and (b) portable Slit lamp (Shin-Nippon) for ocular examination.

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Definitions of different refractive errors

The study was constructed on certain fixed definitions depending on the confidence interval to provide accurate and valid comparisons with other studies of different ethnic origins and cultural settings.

The visual impairment, refractive errors, and amblyopia were defined as follows:
  1. Visual impairment was defined as best corrected visual acuity (BCVA) up to 20/40 in the better eye.
  2. Myopia was defined as a spherical equivalent (SE) of −0.50 D or worse. Hyperopia was defined as SE of +2.00 D or more, and astigmatism as cylindrical power equal to or worse than 0.75 D. The errors of refraction were recorded in SE values to categorize the different types of errors.
  3. Anisometropia was defined as a difference of 1 D (SE) between both eyes.
  4. Unilateral amblyopia was defined as BCVA more than one-line difference between both eyes. Bilateral amblyopia was defined as BCVA of both eyes up to 20/40 [6].

Statistical analysis

Statistical analysis was done using SPSS program (version 21.0; SPSS Inc., Chicago, Illinois, USA). Qualitative data were expressed as numbers and percentage. The nonparametric test of significance (χ2-test) was applied for comparison between groups. Quantitative data were presented as mean and SD.

The P-value was two tailed, and statistical significance was set at 0.05.

  Results Top

The current study was carried out in governmental and private primary school children. It included 1075 students (543 from private school and 532 from governmental school). They were in grades 3–6. Overall, 55% were females and 45% males. The age range was from 9 to 13 years, with a mean of 10.8±0.92 years in private schools and 10.89±0.98 years in governmental schools ([Table 1]).
Table 1: Sociodemographic characteristic of the studied groups

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There was a significantly higher usage of VDTs among private school students (88.8%) compared with 41% in governmental school students (P=0.00001). The types of VDTs used were different, as smart phones were more significantly used in private school students (80.7%) compared with higher desktop-usage among governmental school students (90.4%, P=0.00001) as shown in [Table 2].
Table 2: Distribution and pattern of different visual display terminals use among school children

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Regarding the duration of use, more than half (51.9%) of private school children were recorded to use VDTs since more than 2 years compared with only one-third (34.4%) of governmental school students with a significant difference (P=0.00001). About one-fifth (19.7%) of private school students used VDTs for more than 4 h/day which was a significantly longer period than governmental school students ([Table 2]).

Errors of refraction were significantly more common in the governmental school children (30.8%) compared with the private school children (13.82%, P=0.00). In addition, 8.5% of governmental school children had bilateral amblyopia compared with only 1.3% of private school children, with a significant difference ([Table 3]).
Table 3: Prevalence of refractive disorders among visual display terminals user groups

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The refractive disorders detected by screening in governmental school children were 5.6% compared with those before screening procedures (25.2%); this significant gap was not found in private school children (P=0.000) ([Table 3]).

There was a nonsignificant difference in the types of visual errors detected in both groups; both had astigmatism, myopia, and hypermetropia (χ2=5.38 and P=0.25, [Figure 2]).
Figure 2: Distribution of different types of refractive errors in the visual display terminals user groups.

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The ocular complaints related to computer vision syndrome were significantly more in the private school children (62.7%). The most common complaints were headache (47.3%) followed by eye fatigue manifested as pain in or around the eyes (33.0%), whereas the least common complaint was stinging sensation ([Table 4]).
Table 4: Distribution of different ocular complaints among visual display terminals user groups

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  Discussion Top

This study is the first screening study at Middle Delta Region in Egypt in primary school children to evaluate the effect of VDTs as a risk factor on their eyes. There was a higher significant usage of VDTs (88.8%) among private school students, compared with 41.0% among governmental school students. These findings agree with the American parents report (2015) about their children’s screen time, as 56% of children with higher incomes spent too much time watching TV or playing video games, whereas only 33% of those in lower-income families stated their children spent too much time on these activities [7].

The type of device used by private school students was different, as 80.7% of children used smart phones compared with only 35.8% of governmental school children. These findings agree with smartphone ownership report (2013); they reported that smart phones tend to be quite prevalent at the upper end of the income distribution but much less common among those with lower income levels [8].

Regarding duration of use, 51.9% of private school children used VDTs for more than 2 years and 19.7% used them for more than 4 h/day, with less exposure in the governmental school students. The time of exposure was less than other studies in America on children’s media use; they found that teenagers spent an average of 9 h/day on media use (through TV, internet, smart phones, and so on) for purposes other than school or homework, and that children aged 8–12 years spent about 6 h/day in these activities. The study also suggested that low-income children were less likely than others to have access to computers, tablets, and smart phones. However, when they do have access, they were more likely to spend more time on these devices [9],[10]. This difference may be owing to the difference in the reason of usage, as children in developed countries use it for educational and school duties beside recreation, whereas our students use them mainly for recreation and social communication.

Regarding the visual impairment, the current study revealed a prevalence rate of 13.6% in private school children in comparison with 30.8% in governmental school children, and this was reversely related to VDTs usage. This agrees with El-Bayoumy et al. [11] who reported that the proportion of students with errors and without glasses in Cairo was higher among families of low socioeconomic status. This difference can be explained, as visual disorders have a strong genetic component and are unrelated to acquired factors such as VDTs usage [12],[13]. Many studies found that there was no good evidence that VDTs users are more likely to become short-sighted or develop any other forms of eye defects [14].

In the present study, the VDTs users had many ocular complaints rather than visual disorders in a significant value (62.7%). Headache was the most common complaint (47.3%) followed by eye fatigue (33.0%). Many studies reported that these children may experience problems similar to adults such as eye discomfort, fatigue, blurring of vision, dry eyes, and eye strain and others resulting from improper use of computers [15],[16]. Most studies had shown that the increase in the time spent on computers have led to the prevalence of associated asthenopia, and eye strain although this increase was not significant [17],[18]. Other studies explained the increased incidence of headache in VDTs users to be because of the device being viewed at a distance of less than 50 cm and highlighted the fact that the shorter the distance, the more the visual fatigue. This fatigue was because of the disparity between the shorter viewing distance and the individual’s longer dark convergence in certain individuals [19],[20].

In the current study, other ocular complaints such as burning, stinging, and redness were present in higher percentage of students in private school. These complaints may be related to excess near work, as VDTs demand a prolonged near vision task with less frequent breaks. This in turn, will lead to more exhaustion to accommodation. As accommodation is an active process, a stationary position of eyes can lead to more fatigue. A comparative study detected that using VDTs in a task needs prolonged near vision work and was associated with ocular symptoms such as blur, dryness, and asthenopia in a higher significant value when compared with the similar task without using VDTs [5].

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3], [Table 4]


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