Sudanese Journal of Ophthalmology

: 2018  |  Volume : 10  |  Issue : 1  |  Page : 18--24

Knowledge, awareness and practice of CVS in digital device users

Shweta Chauhan, Renu Dhasmana, Anuradha Raj 
 Department of Ophthalmology, Swami Rama Himalayan University, Himalayan Institute of Medical Sciences, Dehradun, Uttarakhand, India

Correspondence Address:
Renu Dhasmana
Department of Ophthalmology, Swami Rama Himalayan University, Himalayan Institute of Medical Sciences, Jolly Grant, Dehradun, Uttarakhand


Aim: The aim was to study the knowledge, awareness, and practice of computer vision syndrome (CVS) in digital device users. Materials and Methods: This was an observational study conducted on 504 healthy students of a medical college. The students underwent an interview in the form of a preset questionnaire. Results: The present study comprised a total of 188 (37.3%) males and 316 (62.7%) females with the mean age of 21.98 ± 4.61 years. Awareness about CVS was poor, i.e., only 32% had ever heard of the term CVS of which around 65% could correctly define it. It was noted that more than half of the participants resorted to incorrect methods for relief of ocular symptoms. Social media was the largest source of information (15.1%). The association of age with awareness, knowledge with respect to definition, blink rate, and source of information was highly significant (P = 0.003, 0.001, 0.001, and 0.01, respectively). The association of profession of the participant with knowledge about blink rate and practice of taking a break was found to be highly significant (P = 0.002 and 0.01, respectively). Awareness about the blink rate and practice of closing eyes was significantly associated with the sex of the participant (P = 0.03 and 0.01, respectively). Conclusion: This study shows that the younger generation has significant knowledge about CVS, but there is a gap in practice. A program studying and addressing the barriers to practice needs to be developed for younger generation.

How to cite this article:
Chauhan S, Dhasmana R, Raj A. Knowledge, awareness and practice of CVS in digital device users.Sudanese J Ophthalmol 2018;10:18-24

How to cite this URL:
Chauhan S, Dhasmana R, Raj A. Knowledge, awareness and practice of CVS in digital device users. Sudanese J Ophthalmol [serial online] 2018 [cited 2020 Sep 19 ];10:18-24
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Full Text


Increasing use of digital devices worldwide has resulted in a drastic change in the educational and working sectors, and a lack of legislation mandating standards for video display terminal (VDT) has resulted in a growing number of health complaints which range from headaches and visual fatigue to musculoskeletal strain involving the neck and back.[1] The ocular and nonocular complaints of computer users have been collectively termed as “Computer Vision Syndrome” (CVS). CVS is defined by the American Optometric Association as “a complex of eye and vision problems related to activities, which stress the near vision and which are experienced in relation or during the use of computer.”[2] Headache, blurred vision, dry eyes, eyestrain, burning sensation, redness of eyes, change in color perception, and slow focusing are the main symptoms resulting from improper use of computers.[3] Apart from the duration of usage, factors such as poor lightening, glare, screen brightness, vision problems, and improper workstation setup also account for ocular complaints associated with computer usage.[4] Ocular symptoms including dry eye are associated with reduced blink rate and horizontal gaze, causing wider opening of the palpebral fissure that leads to increased evaporation through the exposed area.[5]

Viewing of digital electronic screens is no longer restricted to desktop and computers located in the workplace. Today, it includes viewing laptops, tablets, computers, electronic book readers, and smartphones. Other portable devices used today for written communication (e.g., text messaging, E-mail, and internet access) have relatively small screens that may necessitate close working distances which increase the demands placed upon ocular accommodation and vergence when compared to the printed materials.[6]

In the images on computer screens, contrast is not sharp, edges of characters are not well defined, and eyes have difficulty focusing. Henceforth, the eyes drift to the resting point of accommodation for which eyes strain to regain focus. This puts strain on the ciliary muscles of the eye, which results in tired eyes. There is often associated dry eye due to reduced blinking rate ie. less than 5 blinks per minute in contrast to 15 blinks / minute in normal subjects. A higher number of individuals suffer from ocular symptoms in comparison to musculoskeletal disorders.[7] The discomfort associated with the computer usage has not yet been proven to result in permanent damage, but may cause a reduction in work accuracy and productivity by as much as 40%.[8]

The present study was proposed to study the knowledge, awareness, and practice of CVS in digital device users as limited studies have been conducted in North India.

 Materials and Methods

This was an observational, cross-sectional study and was approved by the institutional research ethical committee. The study was conducted in accordance with the tenets set forth in the Declaration of Helsinki. The proposed study was conducted from September 2015 to September 2016. The study participants included medical students, doctors, and supportive staff of the medical college. The sample size was calculated using the following formula: N = Z2PQ/d2 × 2.5, where N is the desired sample size, Z is the standard normal deviate usually set at 1.96, P or proportion in the target population is 13%, Q is the proportion in the target population not having particular characteristics, which is calculated by 1 − P, d or degree of accuracy is 0.05, and with absolute error of 5% and study design error of 2.5, the final sample came out to be 498. After obtaining written informed consent, 504 students were enrolled in this study to justify the data.[9]

Inclusion criteria

All the participants included in the study were normal healthy individuals of age ranging from 17 to 40 years and using various digital devices.

Exclusion criteria

Known case of dry eye, contact lens users, those with a history of ocular surgery, chronic systemic or topical drug users, known cases of migraine, known cases of neurological ailments, and known cases of cervical spondylitis were excluded from the study.

The demographic details of the enrolled patients were noted and they underwent an interview in the form of a semi-structured questionnaire adapted from other studies.[10],[11],[12] The population was 100% literate; therefore, all the questions were in English language. A complete medical history was recorded to exclude any systemic disease, ocular disease, ocular surgery, neurological disease, or use of medication.

Statistical analysis

The data obtained were entered into an Excel spreadsheet. Interpretation and analysis of the obtained results was carried out using IBM SPSS version 22 (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: USA) for descriptive and inferential statistics in the form of frequencies and percentages. Pearson's Chi-square test was used to find out the relationship of various variables such as age, sex, and profession with the knowledge, awareness, and practice among the digital device users. P < 0.05 was considered statistically significant.


A total of 504 individuals were included in the study. The mean age was 21.98 ± 4.61 years and the male: female ratio was 1:1.6. [Table 1] shows demographic profile of the participants. It was noted that maximum, i.e., 270 (53.6%) participants were in the age group of ≤20 years, while minimum, i.e., 31 (6.2%) were in the age group of 31–40 years. On the basis of their profession, the participants were divided in three groups – nonmedical, paramedical, and medical. Medical group included senior doctors, postgraduate students, and undergraduate students. The frequency of the participants was 8.7%, 14.7%, and 76.6% in nonmedical, paramedical, and medical profession groups, respectively.{Table 1}

[Figure 1] shows the frequency of use of various digital devices among the participants. Smartphones were the most commonly used device among the participants, i.e., 466 (92.5%) followed by laptops (18.8%).{Figure 1}

It was observed that maximum, i.e., 300 (59.52%) participants were using digital devices for <5 years for 3–6 h/day.

[Table 2] shows that only 162 (32.1%) participants were aware about the condition named CVS, out of which only 115 (22.82%) respondents could define it correctly. It also shows that 335 (66.5%) participants have consulted an ophthalmologist in the past for ocular symptoms. It was noted that 35 (6.9%) participants were aware that they were blinking 5 times less often, while majority of the people were unaware of the reduced blink rate. Social media was the most common source of information in 76 (15.1%) participants, followed by friends/relatives. It was also noted that most of the participants (231 [45.8%]) resorted to some methods for relief of the ocular symptoms. The most common method used was closing the eyes (231 [45.8%]).{Table 2}

The important preventive measure for CVS according to the participants was taking regular breaks (229 [45.4%]) followed by doing eye exercises (117 [23.2%]).

[Table 3], [Table 4], [Table 5] show the association of age, profession, and sex with knowledge, awareness, and practice of CVS. [Table 3] shows the association of age with awareness which was highly significant (P = 0.00).{Table 3}{Table 4}{Table 5}

The association of age with knowledge with respect to definition, blink rate, and source of information was highly significant (P = 0.003, 0.001, and 0.01, respectively). The association of profession of the individual with knowledge about blink rate was found to be highly statistically significant (P = 0.00). The association of profession with the practice of taking a break and moving around was also found to be statistically significant (P = 0.01) [Table 4]. [Table 5] shows that the awareness about blink rate and practice of closing eyes was significantly associated with the sex of the individual (P = 0.03 and 0.01, respectively).

Awareness showed a significant relationship with knowledge about CVS (P = 0.00), but awareness was not significantly associated with practice (P = 0.2) [Table 6].{Table 6}


CVS has been called the number one occupational hazard of the 21st century. Hence, various studies have been conducted to know the prevalence of visual symptoms among computer users across the world.

In the current study, 504 individuals were included, of which 384 (76.6%) were in medical profession and 56% of individuals were in the age group of ≤20 years with a mean age of 21.98 ± 4.61 years. This is in accordance to other studies where majority of the participants were under 20 years of age.[8] It has been noted that majority of newer generation is more dependent on digital devices for work than other individuals.

Majority of the individuals in this study were females, i.e., 62.7%, while the maximum number of participants were undergraduates.[8] In a study conducted in Malaysia, 65% of respondents were females. There is a female predominance probably because there were more females in undergraduate batches when the study was in progress; also probably because men are engaged more in physically challenging occupations (driving, business ventures to mention a few), leaving less challenging occupations (VDT operations, teaching, and others) to female population.[13]

The present study showed that 92.5% of participants were smartphone users followed by laptops and desktops. Globally, cellphones are quickly replacing the laptops and desktop computers as the preferred method of accessing the Internet, i.e., around 73% of people access net with smartphones.[14]

There was preponderance of individuals using digital devices for >3 h but <6 h and had been using them since ≤5 years. In a study conducted in Malaysia, 42.9% of the participants used VDT for >2 h, of which 20% used it for 4–6 h.[15] Some studies have reported that spending >7 h per day on computer at work was a significant predictor of CVS and some reported more pronounced visual symptoms in people spending 8 h daily at a computer.[16],[17]

As far as awareness is concerned, only 32% had ever heard of the term “CVS,” out of which around 65% correctly knew what it actually meant, i.e., a combination of headache, eyestrain, and blur vision that occur as a result of prolonged computer use. In accordance with other studies, some respondents report of screen glare and poor illumination because of their discomfort while working on digital devices.[14] Akinbinu and Mashalla stated that the level of awareness and knowledge of CVS among the people working at security and exchange commission was 40% and 27%, respectively, which was comparable to the present study where only 32% of individuals working at medical college were aware of CVS. Increasing age showed higher level of knowledge about CVS according to Akinbinu and Mashalla. On the contrary, the current study showed that the level of knowledge was highest among younger age group.[18] Besides this, only 66% of respondents have ever consulted an ophthalmologist for ocular complaints. This shows the health-seeking behavior of the study population. Absence of severe symptoms or discomfort can be the reason for not seeking medical/professional aid despite working in a medical college.

Similar to a study conducted in Nigeria, where 47.26% respondents admitted not being aware of the proper ergonomic standards for optimal efficiency, here, 45.4% of respondents were unaware of the same. While majority of the participants in this study were literate, the level of knowledge about CVS was very low, suggesting that a serious knowledge gap exists about CVS in the studied population and possibly in the general population.[14],[16] Though working in medical college, 15% respondents reported social media as the major source of information and for their awareness.

Schlote et al. reported marked reduction and distinct pattern of eye blinking in patients with moderately dry eye during VDT use.[19] On the contrary, in the current study, despite being aware of CVS, participants were not practicing right methods of relief, i.e., blinking frequently.

The present study reported that more than half of the participants resorted to wrong method of getting relief despite being in medical stream. Reddy et al. reported that majority, i.e. 68.8% of respondents were taking breaks in between for relief of symptoms of CVS.[20] On the contrary, in the current study, about a quarter were using the right method that is taking break and moving around. Majority of the digital device operators take break only once, as their employers/caretakers/teachers stretch them for maximum output and increased revenue.[16]

Reddy et al. reported predominant use of eye drops as one of the relieving measures used by individuals of CVS, but in the present study, use of eye drops was used as a practice measure only by 15% of cases.[20]

Sheedy et al. concluded that adjusting the brightness of screen can reduce the chances of CVS, but in the current study, only a small proportion of population was practicing this to reduce symptoms.[21]

Limitations of the study

The main limitation of the study was that other ergonomic parameters associated with CVS such as workstation furniture, workplace illumination, and viewing distance of digital device use were not taken into consideration.


This study showed that age, gender, and profession showed a significant relationship with awareness about CVS. Younger age showed a significant impact on the knowledge about CVS. Although the Internet has provided gambit of information and despite having knowledge and awareness, youngsters are not incorporating/resorting to correct practices in their daily routine. Practice of methods to relieve CVS should be included in curriculum. A program studying and addressing the barriers to practice needs to be developed for younger generation.


The authors would like to thank Mr. Surendra Singh Bhandari, Office Assistant, for technical support and documentation.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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