Computer vision syndrome (CVS) is a group of symptoms such as dry eye, eye strain, headache, diplopia, and blurred vision, which occurs with prolonged use of computers and electronic devices. CVS has different categories with different manifestations under each category that differ from one case to another based on the visual abilities of the individual, besides other factors related to the quality of the used electronic device (31–33). Since the beginning of the Covid-19 pandemic, many countries worldwide have restricted physical activity and movement regarding social isolation and quarantine, affecting daily lives mainly home-based with a virtual life for work, education, shopping, and others (34). Several studies have revealed a decrease in physical activity and an increase in sedentary time during the covid-19 lockdown (35–38).
So, we aimed here to study the prevalence of computer vision syndrome during the covid-19 pandemic in light of the increase in electronic device use and the shift in daily life to be more virtual in work, education, communications, and other activities (39). Our meta-analysis indicated that the overall global prevalence of CVS in the era of covid-19 is 74% higher than the estimated overall prevalence of CVS in a systematic review recently conducted by Anbesu et al.. However, it's in line with CVS prevalence in Ethiopia of 73.21%, as reported in a systematic review conducted by Adane et al. (3, 40). That difference in the prevalence between our study and the other one performed by Anbesu et al. is consistent with the shift in lifestyle in the period of covid-19 to be more virtual and with the increase in the usage of electronic devices for multiple needs (39, 41). In addition, several studies have been conducted to assess the impact of digital device usage during the covid-19 pandemic on eye health, such as the study conducted by Bahkir et al., which found an increase in screen time and 95% of the participants experienced at least one symptom of digital device use such as dry eye, eye pain, eye redness, headache, double vision, and others (42). Furthermore, another study conducted by Alabdulkader et al. reported that the incidence of digital eye strain was 78% which is positively correlated with duration and the number of devices which are used (15) aside from another study conducted by Usgaonkar et al. which found that 89% of the participants were spending most of the time on social media using electronic devices. Hence, they experienced symptoms such as dry eye, headache, and back pain (11).
The sub-group analysis based on the country revealed different prevalence estimates based on the number of studies available per each country and justifying the inclusion criteria. The prevalence of CVS in India was estimated as 78% based on three included studies consistent with a study that reported that the prevalence of digital eye strain in the pre-lockdown period was 64.3% (43). That indicates the impact of increased digital device usage during the lockdown period. Our subgroup analysis revealed a CVS prevalence in Saudi Arabia of 72% based on three included studies. However, this estimate differs from one setting to another. It varies based on the target population, as CVS prevalence was estimated as 43.5% in another Al Subaie et al. study among the Al-Ahsa population. Besides, another study conducted among radiologists revealed an overall prevalence of 65.4% (44, 45). Our sub-group analysis revealed that the highest prevalence of CVS was in Pakistan (99%) based on only one included study, and the lowest prevalence was in Turkey (48%) based on only one study. This significant difference between them is based on the difference in the population's culture, behaviour, and habits (46, 47).
It was estimated that the prevalence of CVS among students was 70% which is consistent with their increased usage of computers and learning tools during the Covid-19 lockdown as most educational institutions and universities transformed their learning to be more virtual during the pandemic (48–50).
Our results revealed the variation in the CVS prevalence from one country to another as shown in the sub-group analysis and besides other conducted studies, such as the study conducted by Ranasinghe et al. among Sri Lankan computer workers, which reported a CVS prevalence of 67.4%, A survey conducted among the instructors in Ethiopia (70.4%), and a Study conducted among undergraduate students in Pakistan (90.5%) (16, 51, 52). The difference in the prevalence estimates may be attributed to the difference in the study setting, study period, socioeconomic characters, awareness of the target population about the preventive measures of using computers and digital devices, and the tool used in the estimation of the prevalence which mainly depends on subjective questions and differs from one study to another.
The subgroup analysis estimated that CVS prevalence was higher in the non-student group (82%) than in students (70%), indicating the harmful impact of the COVID-19 lockdown on increasing smartphone and electronic device usage. That is concurrent with the virtual lifestyle in this period, as most work and communication became through digital electronic devices (53, 54).
Recommendations
The increased prevalence of CVS indicates poor education about this syndrome and the proper ways of using computers and digital devices. Therefore, educational programs should be designed for the general population to increase their awareness of CVS symptoms, the risk factors of this syndrome, the different causes of it, and safety measures to prevent it (55). We should also promote research to identify the prevalence of CVS in other countries lacking data to have a more precise estimate of the prevalence of this syndrome globally.
Strengths and limitations
This is the first conducted meta-analysis to describe the prevalence of CVS in the era of COVID-19, and the data presented here will be the basis for policymakers to design new policies and programs to track this syndrome. This study helped to identify the gap in research on CVS prevalence, which, in turn, helps guide future steps to prevent the occurrence of this syndrome. This study also helped identify the lockdown's impact on eye health, which can alert health institutions of any suspected lockdown in the future. This study was conducted based on the PRISMA. Unfortunately, the number of available studies covering CVS prevalence in a few countries limited the analysis. In addition, the included studies were cross-sectional, so we cannot confirm the causal relationship. Finally, the research presented here was based on the data collected in individual studies in a certain period that may change with time.