• Users Online: 895
  • Print this page
  • Email this page

Table of Contents
Year : 2022  |  Volume : 5  |  Issue : 3  |  Page : 292-298

The prevalence and associated factors of self-reported symptoms of computer vision syndrome among high school teachers in Riyadh: A cross-sectional study

1 Department of Family and Community Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
2 College of Medicine, King Saud University, Riyadh, Saudi Arabia

Date of Submission09-Aug-2021
Date of Decision01-Nov-2021
Date of Acceptance29-Mar-2022
Date of Web Publication08-Jul-2022

Correspondence Address:
Afnan Younis
Assistant Professor, Department of Family and Community Medicine, College of Medicine, King Saud University, Riyadh, P.O.Box 2925, Riyadh 11461
Saudi Arabia
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jnsm.jnsm_99_21

Rights and Permissions

Background: Computer vision syndrome (CVS) is a group of visual and musculoskeletal symptoms that are associated with the use of computers and electronic devices. The use of computers is increasing in the field of education which puts teachers at higher risk of CVS. The severity of CVS symptoms can affect teachers' quality of life and productivity. Aim: This study aims to estimate the prevalence of CVS and its symptoms among Riyadh high school teachers in 2020. The secondary objectives were to determine the factors associated with CVS among high school teachers and to compare between the symptoms of CVS in male and female school teachers. Subjects and Methods: This is an observational cross-sectional study. Data were collected by self-administered questionnaire from teachers working in public high schools in Riyadh, Saudi Arabia, using a multistage random sampling technique. Data analysis including descriptive statistics and Chi-square test was performed using SPSS. Results: The prevalence of experiencing one or more symptoms of CVS among high school teachers was 94.6%. The most common symptom was neck and shoulder pain, reported by 84.9% of high school teachers. Male teachers were 80% less likely to have CVS (odds ratio [OR] = 0.213, 95% confidence interval [CI] [0.079–0.578]). The risk of CVS was higher in those who use electronic devices for more than 5 h (OR = 3.4, 95% CI [1.015–11.4]). Male teachers experienced less headache (OR = 0.504, 95% CI [0.344–0.75]), less neck and shoulder pain (OR = 0.326, 95% CI [0.186–0.57]), and less eyestrain (OR = 0.495, 95% CI [0.308–0.796]) in comparison to female teachers. Conclusion: Female high school teachers are having higher odds of developing CVS than male teachers. School teachers need awareness programs about CVS.

Keywords: Computer usage, computer vision syndrome, digital eye strain, video display terminals

How to cite this article:
Younis A, Alsabbagh L, Alaraifi D, Alsanad G, Algrain A, AlDihan R, Albassam F. The prevalence and associated factors of self-reported symptoms of computer vision syndrome among high school teachers in Riyadh: A cross-sectional study. J Nat Sci Med 2022;5:292-8

How to cite this URL:
Younis A, Alsabbagh L, Alaraifi D, Alsanad G, Algrain A, AlDihan R, Albassam F. The prevalence and associated factors of self-reported symptoms of computer vision syndrome among high school teachers in Riyadh: A cross-sectional study. J Nat Sci Med [serial online] 2022 [cited 2022 Aug 11];5:292-8. Available from: https://www.jnsmonline.org/text.asp?2022/5/3/292/350308

  Introduction Top

Technology has become an inseparable part of our lives. It should come as no surprise that such advanced technology has invaded most prominent fields, including the educational field. Teachers use computers in all aspects of educational process. On the other hand, devices may have a detrimental impact on teachers' overall health.

Using these digital devices for an extended period can lead to a number of symptoms that can be categorized in a spectrum known as computer vision syndrome (CVS). CVS has been defined by the American Optometric Association as a complex of eye and vision problems related to near vision activities involving computer use.[1] People with CVS may experience symptoms that include headaches, blurred vision, eyestrain, and neck discomfort.[2]

Multiple studies have been done to assess the prevalence of CVS considering the high reliance on computer use. It has been found that 73% of bank workers in Ethiopia suffer from CVS.[3] Moreover, the prevalence of CVS among IT professionals working in Chennai was found to be 69.3%.[4]

CVS can be induced by several factors which can be categorized into individual vision problems and/or environmental factors. There has been a common consensus in research literature that the risk of having one or more symptoms of CVS is higher with prolonged use of computers.[5],[6] In addition, being a female was associated with a higher likelihood of developing CVS symptoms.[7] Moreover, sitting arrangements and wrong posture were both major environmental factors that may play a role in developing CVS. An Indian study pointed out that the majority of their study subjects (64.7%) had incorrect head and neck posture, followed by the back posture 58.7%.[8] There were also some environmental factors that might contribute to develop CVS symptoms, including room illumination, screen brightness, and distance from the screen.[9],[10]

As has been indicated by previous studies, a lot of people are experiencing CVS symptoms. Several studies conducted in Saudi Arabia concluded that the most reported symptoms were headache and neck and shoulder pain. As reported in a study conducted among female business and medical students in Riyadh, that showed the prevalence of neck and shoulder pain among students with CVS was 84.3% and 79.7%, respectively.[11] Furthermore, the prevalence of musculoskeletal symptoms was measured among university students in Majmaah, Saudi Arabia, and was found to be 52.7%.[12] In addition, the headache was reported by 52.4% of mobile phone users in Al-Ahsa,[13] and by 81.3% of female nursing students in Riyadh.[14]

Despite that some studies have investigated CVS among various populations in Saudi Arabia, none of them included school teachers.

Considering the technological revolution in schools and educational field as whole, it is important to highlight the effect of technology on teachers' health. This study aims to estimate the prevalence of CVS and its symptoms among high school teachers in Riyadh in 2020. The secondary objectives were to determine the associated factors with CVS among high school teachers and to compare these symptoms between male and female school teachers.

  Subjects and Methods Top

A cross-sectional study was conducted among Saudi male and female teachers working in public high schools in Riyadh, Saudi Arabia, from September 2019 to May 2020. Teachers with any diagnosed ocular disease other than refractive errors and astigmatism were excluded from the study.

The sample size was calculated using the standard formula for cross-sectional studies considering 5% significance, 5% precision, and CVS prevalence of 43.5%.[13] After adding 10% as compensation for lost or incomplete data, the required sample size was 415 participants.

The sampling technique was multistage random sampling, in which the five administrative regions (North, South, East, West, and middle) of Riyadh city were used; from each region, 4 schools were selected randomly (2 female and 2 male schools) to end up with 20 schools, teachers were recruited randomly from each school.

The questionnaire was divided into two parts, the first part for demographic information that included age, gender, and subject taught by the teacher while the second part consisted of symptoms of CVS and its associated factors during the previous month. The list of the CVS symptoms was provided and participants had to choose the severity of each symptom on a 4-point Likert scale (0 – not at all, 1 – -mild, 2 – moderate, and 3 – severe). The severity of symptoms was defined as follows: mild symptom is a transient symptom that persists for few minutes to hours, a moderate symptom is a symptom that persists for few hours and subsides after rest or sleep, while severe symptom is a symptom that needs medical attention. The symptoms included (headache, burning eye sensation, eye redness, blurred vision, dry eye or tearing, neck and shoulder pain, double vision, and difficulty refocusing the eyes).

Questions about the associated factors included the duration of using electronic devices in a dark room and in a bright room, duration and frequency of breaks during the usage of electronic devices, sitting position and distance to screen, using monitor filters, screen brightness, room illumination, the use of night mood in devices, and awareness about the 20-20-20 rule.

The questionnaire was adopted with some modifications from Al Tawil et al., after getting the authors' permission.[11] The questionnaire was piloted on 60 subjects before the actual study and these subjects were not included in the actual study.

Data were analyzed using IBM Corp. IBM SPSS statistics for windows (Version 25.0) [computer software]. New York: IBM Corp. 2017.[15] Descriptive statistics included mean and standard deviation for continuous data and frequencies and percentages for categorical variables. Chi-square test was performed to test the association between main outcome and different demographic variables.

All participants signed the informed consent form before enrolment and approval was gained from the Institutional Review Board at King Saud University on 8-12-2019, the approval number is E-19-4437.

  Results Top

This study included 451 high school teachers comprising 235 (52.1%) female teachers and 216 (47.6%) male teachers. Majority of participants 40.8% were teaching science, 24.6% social studies, and 12.9% Islamic subjects. Regarding the mainstream device, the largest proportion of high school teachers 69.4% were using tablets/mobile phones, 25% were using laptops, and the minority 5.1% were using desktops. Twenty-nine percent of high school teachers spent more than 5 h on electronic devices, while half of them 50.3% spent 2–4 h, and only 20% spent <2 h. The majority of teachers 80.3% took frequent breaks while using electronic devices. The frequency of breaks varied among teachers, 34.6% took breaks every 30 min, 25.1% took breaks every hour, and only 18% took breaks after more than 1 h of using their devices. Almost half of the high-school teachers 48.3% kept their devices <40 cm away, while only 4.7% of high school teachers kept their devices >76 cm away from their eyes. The majority of high school teachers 58.8% used their devices while their back is bent, 23.3% sat with an upright position with straight back, and only 18% used their devices while lying down. Sixty percent of high school teachers used bright mode on their devices, while only 2.4% used dull mode. Only 15% of our participants were aware of 20-20-20 rule, while 84.3% were not aware of it [Table 1].
Table 1: Characteristics of study subjects (n=451)

Click here to view

In order to calculate the prevalence of CVS in this population, any participant experiencing one or more symptoms of CVS was considered as having CVS. Nearly, all of the participants were having one or more CVS symptoms with a prevalence of 94.6%. The most commonly reported symptom was neck and shoulder pain 84.9%, followed by eye strain 80.3%. On the other hand, the least reported symptoms were eye redness and double vision (49.2% and 48.3% respectively). Most of the symptoms were reported as mild, with blurred vision being the most common mild symptom 38.4%, followed by eyestrain 37.9%. The most commonly reported severe symptom was neck and shoulder pain 21.5%. The least reported severe symptoms were headache 3.3% and eye strain 3.3% [Table 2].
Table 2: Prevalence of computer vision syndrome symptoms by severity

Click here to view

Regarding factors associated with CVS, male teachers were 80% less likely to have CVS with odds ratio (OR) = 0.213, (P = 0.001, 95% confidence interval [CI] = 0.079–0.578). Spending more than 5 h on electronic devices had 3.4 times more odds of developing CVS in comparison to spending <2 h on a device (OR = 3.4, [P = 0.037, 95% CI = 1.015–11.4]). Teachers who took breaks less frequently with more than an hour in between breaks were less likely to develop CVS than those who took breaks every 30 min OR = 0.235, (P = 0.006, 95%CI = 0.077–0.713). Other factors did not show any statistical significance and are shown in [Table 3].
Table 3: Association between computer vision syndrome and study variables

Click here to view

Gender comparison was done to compare symptoms between males and females. Female high school teachers were experiencing significantly greater symptom prevalence than their male counterparts. Being a male high school teacher decreased the likelihood of experiencing headaches by 50% (OR = 0.504, P = 0.000, 95% CI = 0.344–0.740). In addition, neck and shoulder pain was 66% less in males (OR = 0.326, P = 0.000, 95% CI = 0.186–0.570). Moreover, dry eye was reported by more female teachers OR = 0.609, (P = 0.011, 95% CI = 0.416–0.893). Furthermore, male school teachers were about 50% less likely to have eye strain OR = 0.495, (P = 0.003, 95% CI = 0.308–0.796). Burning eye sensation was also experienced by less males compared to females OR = 0.638, (P = 0.026, 95% CI = 0.430–0.948). Other symptoms did not show any statistically significant association with gender [Table 4].
Table 4: Association between gender and different computer vision syndrome symptoms

Click here to view

  Discussion Top

Currently, technology plays a major role in the education process, resulting in greater computer use. This study may be the first of its kind in the Riyadh region which studies the effects of prolonged computer use among secondary school teachers.

The prevalence of CVS in this study is 94.6%, which is higher than most reported studies. A study conducted in Iraq has shown that the prevalence of CVS was 89.02%.[16] 73.9% of the secretaries and data processors at University of Gondar in Ethiopia had experienced CVS.[17] A lower prevalence was reported in Nigeria accounted for 65% of working-class adults.[18]

Neck and shoulder pain was the most reported symptom by respondents (84.9%) which also was the most reported “severe” symptom. A study conducted in Jamaica found that neck and shoulder pain was reported by (75.1%) and (65.5%) of the study population, respectively.[19] Similarly, it was the most frequently experienced extraocular symptom in India.[20]

Musculoskeletal pain and especially neck and shoulder pain depends on many factors such as incorrect posture and the level of the device in relation to the level of the body. In the current study, musculoskeletal pain showed the highest prevalence among other CVS symptoms, which demonstrates the need to create awareness programs among school teachers about correct computer-use techniques.

The second-most experienced symptom in this study was eye strain, reported by (80.3%) of teachers. A higher prevalence (89%) was reported in India among medical students.[20] While in Ethiopia, eye strain was the second most experienced symptom with prevalence of (47.6%) among computer users.[6] Eye strain is caused by the repeated eye movement from the screen, keyboard, and/or documents.[21]

Blurred vision, burning sensation, and dry eyes were also common symptoms experienced by participants. Blurred vision showed a prevalence of (69.6%), it was reported by other studies as the most frequent symptom among working adults, as has been reported in Ethiopia.[3],[17] Burning sensation was also a common ocular symptom among university students in several studies.[20],[22],[23]

On the other hand, a headache was one of the most reported symptom associated with computer use,[9],[23],[24] in this study, it was reported by (60.8%) of participants. The least reported symptom was double vision with prevalence of (48.3%); similarly, it was the least reported symptom in Majmaah (23.3%)[12] and Nigerian working-class adults (3.3%).[18]

In this study, females had significantly higher risk of developing headache, burning sensation, dry eyes, eye strain, and neck and shoulder pain. This finding goes in line with results from previous research on other populations.[7],[9],[25] This could be because females usually pay more focus on their symptoms than males.[26] Other symptoms did not show any significant association with gender. Headache and neck and shoulder pain were also significantly higher among female undergraduate university students in Jamaica[19] as was reported in India.[27] This could be because that females normally have shorter stature affecting their arms, wrists, and reach which may affect the reading distance from a hand-held computer or their height on a desk-mounted computer requiring them to have chin-up position, increasing musculoskeletal symptoms.[9],[28],[29] However, a study in Iraq reported that neck and shoulder pain was significantly higher in males.[16] Eye dryness is a common complaint in mobile phone users,[13] it was significantly higher in females in our study. Hormonal imbalance can alter the tear film stability; in females, the Meibomian Gland (MG) is under the control of estrogen; hence, any hormonal imbalance can alter the secretion of the tear film and result in MG dysfunction which is the most common subtype of dry eye, this may explain why females are more vulnerable than males to have dry eye.[30]

Regarding the associated factors, the present study revealed that the occurrence of CVS is significantly associated with using the computer for more than 5 h. Logaraj et al. found that increasing the number of hours spent on computer increases the risk of CVS significantly.[27] Similarly, a study in Ethiopia showed that workers who used computers for >4.6 h daily were more likely to develop CVS.[6] Several studies have also revealed the strong association between prolonged use of computer and other devices and CVS symptoms.[7],[22],[31]

Taking frequent breaks while using the computer could reduce the negative effect of CVS.[19],[27] However, in this study, we noticed that taking a break after a longer duration of work was associated with a lower risk of having CVS, which could be due to misunderstanding of the break concept; hence, many people spend most of the break duration using mobile phones instead of relaxing and stretching, which could be an opportunity for future research to investigate the activities that people do in their break time. Researchers recommend short breaks at regular intervals to re-establish the ability of the users to resume their work.[32]

In terms of study limitations, this study used a subjective method, i.e., self-reported questionnaire, in assessing the symptoms. The accuracy of the diagnosis can be confirmed by an ophthalmologist in future research. Not including the gaze, blinking rate, and the angle of the device were also limitations.

  Conclusion/Recommendations Top

The prevalence of CVS in high school teachers is high. Female school teachers have a higher risk of developing CVS compared to male school teachers. Awareness programs directed to school teachers are needed, as they are spending a lot of time in front of digital screens.

Recommendations for future researches include a prospective cohort study of computer users to properly investigate the relationship between CVS symptoms and the risk factors, cross-sectional study including ophthalmic examination for more accurate diagnosis of CVS. In addition, researches can assess the influence of prolonged electronic device usage on sleep, social life, and work productivity. Furthermore, as people are using their electronic devices throughout the day, we recommend to look for the activities done during break time. We assume there will be major differences between participants who spend their breaks using their phones or other devices and participants who spend their breaks stretching, relaxing, and meditating. Finally, it would be crucial to reassess the prevalence of CVS and its associated factors during this critical time under the effect of lockdown and distance learning as a consequence of COVID-19, which might have had a significant impact on teachers and students.


This research was supported by the College of Medicine Research Center, Deanship of Scientific Research, King Saud University, Riyadh, Saudi Arabia.

The authors are greatly thankful for Altawil et al for giving us permission to use their tool, as well as Mohammed A. Alasmari, Abdullah S. Alsaif, Raghad M. Alajlan and Lamya A. AlMadi for their contributions in data acquisition.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Loh K, Redd S. Understanding and preventing computer vision syndrome. Malays Fam Physician 2008;3:128-30.  Back to cited text no. 1
Computer Vision Syndrome. Available from: https://www.aoa.org/patients-and-public/caring-for-your-vision/protecting-your-vision/computer-vision-syndrome. [Last accessed on 2019 Oct 27].  Back to cited text no. 2
Assefa NL, Weldemichael DZ, Alemu HW, Anbesse DH. Prevalence and associated factors of computer vision syndrome among bank workers in Gondar City, northwest Ethiopia, 2015. Clin Optom (Auckl) 2017;9:67-76.  Back to cited text no. 3
Arumugam S, Kumar K, Subramani R, Kumar S. Prevalence of computer vision syndrome among information technology professionals working in Chennai. World J Med Sci 2014;11:312-4.  Back to cited text no. 4
Rosenfield M, Bababekova Y, Portello JK. Prevalence of computer vision syndrome (CVS) and dry eye in office workers. Invest Ophthalmol Vis Sci 2012;53:5459.  Back to cited text no. 5
Dessie A, Adane F, Nega A, Wami SD, Chercos DH. Computer vision syndrome and associated factors among computer users in Debre Tabor Town, Northwest Ethiopia. J Environ Public Health 2018;2018:4107590.  Back to cited text no. 6
Rahman Z, Sanip S. Computer user: Demographic and computer related factors that predispose user to get computer vision syndrome. Int J Bus Humanit Technol 2011;1:84 91. Available from: http://www.ijbhtnet.com/journals/Vol_1_No_2_September_2011/11.pdf. [Last accessed on 2021 Jan 27].  Back to cited text no. 7
Portello JK, Rosenfield M, Bababekova Y, Estrada JM, Leon A. Computer-related visual symptoms in office workers. Ophthalmic Physiol Opt 2012;32:375-82.  Back to cited text no. 8
Shantakumari N, Eldeeb R, Sreedharan J, Gopal K. Computer use and vision-related problems among university students in Ajman, United Arab emirate. Ann Med Health Sci Res 2014;4:258-63.  Back to cited text no. 9
[PUBMED]  [Full text]  
Kozeis N. Impact of computer use on children's vision. Hippokratia 2009;13:230 1. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776336/pdf/hippokratia 13 230.pdf. [Last accessed on 2021 Jan 27].  Back to cited text no. 10
Al Tawil L, Aldokhayel S, Zeitouni L, Qadoumi T, Hussein S, Ahamed SS. Prevalence of self-reported computer vision syndrome symptoms and its associated factors among university students. Eur J Ophthalmol 2020;30:189-95.  Back to cited text no. 11
Sirajudeen MS, Muthusamy H, Alqahtani M, Waly M, Jilani AK. Computer-related health problems among university students in Majmaah region, Saudi Arabia. Biomed Res 2018;29:2405-15.  Back to cited text no. 12
Al Subaie M, Al-Dossari S, Bougmiza M. Computer vision syndrome among mobile phone users in Al-Ahsa, Kingdom of Saudi Arabia. Al Basar Int J Ophthalmol 2017;4:99.  Back to cited text no. 13
El Kiweri IA, Al Ghamdi NA. Electronic devices : Content use and health effects in Saudi female nursing students. Int J Nurs Health Sci 2015;2:21-7.  Back to cited text no. 14
IBM Corp. IBM SPSS Statistics for Windows (Version 25.0) [Computer Software]. New York: IBM Corp.; 2017.  Back to cited text no. 15
Ahmed D, Alwan E. Prevalence of computer vision syndrome in Erbil. Zanco J Med Sci 2018;22:115-9.  Back to cited text no. 16
Alemayehu M. Prevalence of self reported computer vision syndrome and associated factors among secretaries and data processors who are working in university of Gondar, Ethiopia. J Biol Agric Healthc 2014;4:33-7.  Back to cited text no. 17
Agbonlahor O. Prevalence and knowledge of computer vision syndrome (CVS) among the working class adults in F.C.T. Nigeria. J Niger Optom Assoc 2019;21:49-60.  Back to cited text no. 18
Mowatt L, Gordon C, Santosh AB, Jones T. Computer vision syndrome and ergonomic practices among undergraduate university students. Int J Clin Pract 2018;72:1-7. DOI:10.1111/ijcp.13035.  Back to cited text no. 19
Basnet A, Basnet P, Karki P, Shrestha S. Computer vision syndrome prevalence and associated factors among the medical student in Kist Medical College. Nepal Med J 2018;1:29-31.  Back to cited text no. 20
Munshi S, Varghese A, Dhar Munshi S. Computer vision syndrome – A common cause of unexplained visual symptoms in the modern era. Int J Clin Pract 2017;71:1-5. DOI:10.1111/ijcp.12962.  Back to cited text no. 21
Al Rashidi S, Alhumaidan H. Computer vision syndrome prevalence, knowledge and associated factors among Saudi Arabia University Students: Is it a serious problem? Int J Health Sci (Qassim) 2017;11:17-9.  Back to cited text no. 22
Noreen K, Batool Z, Fatima T, Zamir T. Prevalence of computer vision syndrome and its associated risk factors among under Graduate medical students. Pak J Ophthalmol 2016;140:140-6.  Back to cited text no. 23
Pulla AA, Samyuktha N, Kasubagula S, Kataih A, Banoth D, Addagatla H. A cross sectional study to assess the prevalence and associated factors of computer vision syndrome among engineering students of Hyderabad, Telangana. Int J Community Med Public Health 2018;6:308-13.  Back to cited text no. 24
Ranasinghe P, Wathurapatha WS, Perera YS, Lamabadusuriya DA, Kulatunga S, Jayawardana N, et al. Computer vision syndrome among computer office workers in a developing country: An evaluation of prevalence and risk factors. BMC Res Notes 2016;9:150.  Back to cited text no. 25
Muller CF. Health Care and Gender. New York, USA: Russell Sage Foundation; 1992. p. 258.  Back to cited text no. 26
Logaraj M, Madhupriya V, Hegde S. Computer vision syndrome and associated factors among medical and engineering students in Chennai. Ann Med Health Sci Res 2014;4:179-85.  Back to cited text no. 27
[PUBMED]  [Full text]  
Eduardo CS, Mario FJ, Lys ER. Risk factors for computer visual syndrome (CVS) among operators of two call centers in São Paulo, Brazil. Work 2012;41 Suppl 1:3568-74.  Back to cited text no. 28
Bingefors K, Isacson D. Epidemiology, co-morbidity, and impact on health-related quality of life of self-reported headache and musculoskeletal pain – A gender perspective. Eur J Pain 2004;8:435-50.  Back to cited text no. 29
Sullivan BD, Evans JE, Dana MR, Sullivan DA. Influence of aging on the polar and neutral lipid profiles in human meibomian gland secretions. Arch Ophthalmol 2006;124:1286-92.  Back to cited text no. 30
Agarwal S, Goel D, Sharma A. Evaluation of the factors which contribute to the ocular complaints in computer users. J Clin Diagn Res 2013;7:331-5.  Back to cited text no. 31
Henning RA, Jacques P, Kissel GV, Sullivan AB, Alteras-Webb SM. Frequent short rest breaks from computer work: Effects on productivity and well-being at two field sites. Ergonomics 1997;40:78-91.  Back to cited text no. 32


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


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
Subjects and Methods
Article Tables

 Article Access Statistics
    PDF Downloaded37    
    Comments [Add]    

Recommend this journal