Prevalence and Associated Factors of Computer Vision Syndrome Among the Employees of a Selected University in Mangaluru, Karnataka- A Cross-sectional Study

INTRODUCTION

In today’s technology-driven world, computer devices and gadgets have become essential in almost every aspect of life, with ∼75% of daily activities involving computer use. While computers have made tasks easier and significantly boosted productivity in institutions, offices, and homes, they have also introduced health risks that negatively affect the quality of life for users. Computers impact various cognitive, social, and physical aspects of daily life, especially for frequent internet users. Most people spend a large portion of their day, often more than a quarter, working or browsing on computers. Consequently, the strain on eyes and vision has increased substantially.^[1,2]

The American Optometric Association defines computer vision syndrome (CVS) as a range of eye and vision problems linked to near-vision tasks, particularly during computer use. Symptoms include eye strain, tiredness, soreness, watering, irritation, dryness, blurred vision, difficulty changing focus, double vision, and colour perception changes, along with related neck, back, and shoulder pain. Prolonged computer use can lead to decreased visual power and other vision impairments. With the rise in prolonged computer usage, computer-related health issues have surged rapidly. Extended exposure to video display terminals (VDTs) has resulted in visual and ergonomic problems collectively termed CVS.^[3]

Globally, nearly 60 million people suffer from CVS, with about one million new cases emerging annually. The prevalence among computer users ranges from 64–90%.^[4,5] In India, more than 40 million individuals use computers, and ∼80% of them experience discomfort associated with CVS. The most frequently reported symptoms include eye strain, headaches, blurred vision, and dry eyes. CVS encompasses visual symptoms that arise when the visual demands of a computer task exceed the eyes’ normal capacity, causing discomfort. Prolonged exposure to such discomfort triggers a cascade of symptoms categorized as CVS.^[6]

CVS broadly covers multiple eye- and environment-related conditions caused when the visual demands of computer tasks exceed users’ visual abilities, resulting in difficulty focusing on screen images. The eyes must repeatedly focus and refocus thousands of times daily to view pixelated images, which can cause strain. Visual problems are among the most common health issues linked to extensive computer use. Factors such as lack of access to protective equipment, high workloads, and poor ergonomic knowledge contribute to the high burden of CVS, especially in developing countries.^[7,8] Fortunately, CVS can be largely prevented through simple, affordable measures. As computer use continues to rise among employees, adopting preventive strategies is crucial. Beyond health concerns, CVS can reduce workplace efficiency and degrade work quality.^[9,10]

Ophthalmologists today are increasingly encountering patients with vision issues resulting from extended and intensive computer use. Excessive near work, especially on computers, can push the eyes beyond their natural comfort level, resulting in visual discomfort. Continuous exposure often leads to a combination of symptoms identified as CVS.^[11,12] With this context, this study was conducted to investigate the prevalence of CVS and its associated factors among computer users, aiming to identify key ergonomic and behavioural risks to improve eye health and workplace productivity. Understanding these associations is essential to develop effective preventive strategies among populations with prolonged computer exposure.

MATERIAL and METHODS

A cross-sectional observational study was conducted at Yenepoya (Deemed to be University), Mangaluru, Karnataka, between August 2022–2023. The research protocol received approval from both the Scientific Review Board and the Institutional Ethics Committee [Approval number: YEC-2/1015]. Prior to participation, individuals were given detailed information about the study through a participant information sheet, and informed consent was obtained. Participants were fully informed about the study’s objectives and procedures. Additionally, formal permission was granted by the relevant administrative authorities.

Inclusion criteria for the study were male and female participants aged >18 years, employees using a computer (desktop or laptop) for >3 h/day, employees like office superintendents, personal assistants, first and second division clerical staff, with at least 1 month of experience in their current job, and those diagnosed with refractive errors and using spectacles. Participants were excluded if they had eye infections at the time of the study, eye complications caused by other medical conditions such as diabetic retinopathy, or if they were unwilling to participate.

Sample size was checked for computer users using the formula n = (Z² × p × q)/d²(Cochran formula). For the present study, an expected prevalence (p) of 70% (0.70) was assumed. Thus, q = 0.30. The allowable error (d) was set at 7% (0.07). The calculated sample size was 150. Considering a non-response rate of ∼5–10%, the sample size was rounded up to 160.​ A total of 160 participants were selected through a non-probability purposive sampling method.

The CVS questionnaire and the checklist on associated factors were developed by the researcher based on the study objectives and a review of relevant literature.^[2-4,8,9] These tools were then validated by seven subject experts. A pretest was conducted with 12 participants to evaluate the feasibility of the data collection tools. Internal consistency reliability of the CVS questionnaire was assessed using Cronbach’s alpha, and the reliability coefficient was 0.79. Test-retest reliability of the associated factors of the CVS checklist was assessed using Cohen’s kappa coefficient, which was 0.82.

The data was collected using a demographic proforma, CVS questionnaire, and checklist on associated factors of CVS. The Demographic proforma included age, gender, education, occupation, years of working experience, years of working with computers, working hours with computers, self-reported pre-existing ocular condition, and previous knowledge regarding CVS.

The CVS questionnaire consisted of 16 items, such as burning sensation, itching, foreign body sensation, tearing, excessive blinking, eye redness, eye pain, heavy eyelids, dryness, blurred vision, double vision, difficulty focusing for near vision, increased light sensitivity, coloured halos around objects, feeling of worsening eyesight, and headache. Participants are asked to indicate the frequency and intensity. Frequency was assessed in terms of never, occasionally, and always, while intensity was measured as moderate or severe. The total scores were interpreted as a score range of 1-25, which indicated mild CVS, 26–45 indicated moderate CVS, and 46-64 indicated severe CVS.

Checklist on associated factors of CVS consisted of 10 items such as seating position, viewing distance over 40 cm, computer screen at eye level, use of blue lens spectacles, ergonomic chair use, voluntary blinking, taking regular breaks, adjusting screen brightness to ambient light, use of anti-glare screen, and use of natural light. Participants have to respond with yes or no. This study was performed in the workplace of the participants. It took around 15 min for each participant to complete the questionnaire. Confidentiality was maintained.

RESULTS

The study population mainly comprised females aged 25–30 years. Most of them were graduates (61.3%) and were working as second division clerks (56.9%). A large number had 1–5 years of work experience (65.6%) and computer use (61.9%). Nearly half of them used computers for >7 h a day (44.4%), showing high screen exposure. About 1/3 had existing eye problems (33.7%), mainly short-sightedness (17.5%) and long-sightedness (14.4%). Most participants had prior knowledge about CVS (68.1%), and the main source of information was mass media (76.1%) [Table S1].

The overall prevalence of CVS was 46 (28.8%), with 40 (25%) presenting mild symptoms and 6 (3.8%) presenting moderate symptoms [Table 1].

The majority of participants reported practicing several positive ergonomic and eye care habits while using computers. Notably, 89.4% had an appropriate seating position, 82.5% kept the top of their computer at eye level, and 81.9% used an ergonomically comfortable chair. Additionally, 75.6% maintained a viewing distance of more than 40 cm, and 73.1% each reported taking regular breaks and adjusting screen brightness according to ambient light. However, fewer participants reported using protective aids: only 24.4% used blue lens spectacles and 29.4% used anti-glare screens. Just over half (53.1%) had a habit of voluntary blinking, and 68.1% used natural light while working on the computer [Table 2].

Table 3 demonstrates a significant association between the severity of CVS and both working hours on the computer (χ² = 10.489, p = 0.005) and the presence of eye problems (χ² = 20.359, p <0.001), indicating that individuals who spend longer hours on computers and those with existing eye issues are more likely to experience CVS symptoms.

There was a significant association between the associated factors of CVS and demographic variables. Seating position was significantly associated with years of working experience (χ² = 33.732, p = 0.028), working hours on the computer (χ² = 6.423, p = 0.040), and presence of pre-existing ocular conditions (χ² = 20.795, p <0.001). The use of a comfortable chair was significantly associated with occupation (χ² = 11.264, p = 0.010), years of working experience (χ² = 38.798, p = 0.007), and presence of pre-existing ocular conditions (χ² = 4.250, p = 0.039). Voluntary blinking was associated with occupation (χ² = 8.162, p = 0.043) and working hours on the computer (χ² = 4.250, p = 0.039). Taking regular breaks had a significant association with occupation (χ² = 9.719, p = 0.021) and working hours (χ² = 12.020, p = 0.002).

DISCUSSION

In today’s digitally driven environment, both personal and professional activities increasingly rely on the use of computers and electronic screens. This rise in digital engagement has brought about various health-related concerns, particularly those affecting eye health and workplace ergonomics. One of the most common conditions emerging from prolonged screen exposure is CVS. It is characterized by symptoms such as visual fatigue, dry eyes, headaches, and blurred vision, which can significantly impact comfort and productivity. CVS is influenced by several factors, including the duration of screen use, posture, lighting conditions, and user habits. Recognizing and addressing these risk factors is essential in creating effective prevention and management strategies to reduce visual strain and promote well-being in digital work environments.

This study revealed that a majority of the participants (40%) belonged to the age group of 25–30 years. This finding aligns with the Ethiopian cross-sectional survey among university instructors, which found that 70.4% had CVS, with 54.6% of affected individuals falling in the age range of 24–33 years.^[9] Similarly, Ranasinghe et al. conducted a study among office workers in Sri Lanka, where the majority of participants (48.1%) were aged 20–29 years.^[12] This age distribution is typical for university employees, especially those who use computers frequently, such as teaching assistants, office staff, and early-career academics. People in the 25–30 age group are often at the beginning of their careers, where using digital technology is common and often necessary for long hours. The large number of young adults in this study may be because they rely heavily on digital tools for both academic and office work. They often use multiple devices like computers, tablets, and smartphones at the same time, sometimes without following proper screen-time breaks or ergonomic practices. These habits can increase their risk of developing symptoms of CVS.

In the present study, the majority of participants (25%) were found to have mild CVS, while 3.8% had moderate CVS. These findings suggest that most affected individuals were experiencing early-stage symptoms such as eye strain, dryness, or mild headaches. While mild cases may not significantly interfere with daily tasks, they still indicate visual fatigue that can progress if not addressed through timely preventive measures. This is consistent with the study of engineering students in Ethiopia that reported a CVS prevalence of 41.7%, with no specific breakdown of severity.^[13] However, another study among radiologists in Saudi Arabia found that 69.1% had mild CVS, 25.4% moderate, and 5.5% severe symptoms.^[14] Their findings are comparable to ours in terms of mild and moderate cases, indicating that even health professionals are not exempt from CVS due to prolonged screen exposure. In contrast, a study on Ethiopian university instructors found higher severity: 32.2% had moderate and 39.2% had severe CVS.^[9] The difference in severity levels may be attributed to longer daily screen time, fewer ergonomic adjustments, and lower awareness of preventive practices in that population. These comparisons indicate that factors such as workplace culture, awareness levels, and availability of preventive measures significantly influence the severity of symptoms.

Our relatively lower percentage of moderate cases might reflect either a lower exposure risk or better screen management practices, such as taking regular breaks, adjusting monitor position, etc. However, the presence of even mild CVS symptoms in a quarter of the participants highlights the need for early intervention and regular eye health monitoring to prevent symptom progression.

This study found that the associated factors of CVS were not taking regular breaks (27.5%), not using anti-glare screens (70.6%), and not adjusting computer brightness (26.9%). These behaviours contribute to prolonged eye strain and discomfort by increasing exposure to glare, improper lighting, and continuous screen use without rest. This aligns with the study that reported comparable associated factors among academic staff in Ethiopia: 27.5% did not take regular breaks, 66% did not use anti-glare screens, and a higher proportion (48%) did not adjust computer brightness.^[15] This consistency underscores the significance of ergonomic and behavioural practices in the development of CVS. Similarly, another study conducted among university students in Saudi Arabia reported that prolonged screen exposure, inadequate rest breaks, and improper viewing practices were significantly associated with CVS symptoms.^[16] Likewise, another cross-sectional study conducted among office workers in Nepal identified poor ergonomic practices, inappropriate screen brightness, and lack of preventive eye care measures as important contributors to CVS.^[17] These collective findings highlight the need for workplace interventions focusing on promoting regular breaks (such as the 20-20-20 rule), using anti-glare screens, and encouraging optimal screen brightness adjustments. Raising awareness and providing ergonomic training can effectively reduce CVS prevalence and severity among employees engaged in intensive computer work.

The present study found a statistically significant association between the prevalence of CVS and the number of working hours spent on computers. This indicates that longer computer use is strongly linked to higher CVS prevalence.

This finding aligns with the study in Sri Lanka, which shows that computer office workers who used screens for more than 6 hours daily had significantly higher odds of experiencing CVS.^[12] Similarly, a study among university staff in Ethiopia showed that extended daily computer use was significantly associated with CVS.^[15] These results emphasize the importance of managing working hours, encouraging regular breaks, and adopting ergonomic practices to mitigate the risk of CVS among employees engaged in intensive computer work.

The findings of this study revealed a significant association between seating arrangements and the presence of ocular conditions among participants. This indicates that improper seating posture or workstation setup may contribute to the development of eye discomfort and symptoms related to CVS. Ergonomic factors such as incorrect chair height, poor screen positioning, and inadequate support can lead to increased eye strain by causing users to adopt awkward postures or view screens at uncomfortable angles. These factors have been consistently identified in previous studies as key contributors to visual fatigue and eye-related symptoms in computer users.^[18,19] Improving seating ergonomics through proper workplace design and user education will be essential to minimize eye problems and enhance the comfort of individuals engaged in prolonged computer use.

This study had a few limitations. The data were based on self-reported responses, which might be affected by inaccurate reporting. Also, the study was limited to a few employees from one university, so the results may not apply to other settings.

CONCLUSION

The findings of this study demonstrate that CVS is a growing concern among university employees who are exposed to prolonged computer use. The condition was found to be most prevalent in younger age groups and was commonly associated with modifiable risk factors such as lack of regular screen breaks, absence of anti-glare screen use, and improper adjustment of screen brightness. Additionally, significant associations were observed between CVS and working hours, as well as poor seating ergonomics. These results emphasize the importance of promoting eye health through ergonomic practices, awareness programs, and preventive strategies in the workplace in reducing the burden of CVS and enhancing employee well-being.