Introduccion:

Currently, technology is a part of our daily life and has become indispensable; electronic devices such as cell phones, tablets, computers, and televisions have been brought into our homes with increasing frequency for recreational and/or vocational purposes. In the last century, the modern world has become addicted to the screens of such devices, thus generating a great demand for daily use; these make life easier for many people worldwide; however, their inappropriate use can cause damage to health¹.

The year 2020 brought a pandemic due to sars-cov2, which altered the lifestyle of many people. The primary measure was confinement and social distancing, depriving physical and social interaction. On the other hand, this promoted relationships through electronic devices; thus, people relied on devices to obtain information or for entertainment².

The american optometric association (AAO) defines the term computer vision syndrome (CVS) as a group of eye and vision problems related to excessive and prolonged use of electronic equipment¹.

For example, a person who dedicates a large part of their day to being in front of a computer as an employee or student performs 12,000 to 35,000 head and eye movements daily, and their pupils react 5,000 to 17,000 times. Consequently, symptoms such as dry eye, blurred vision, eye pain, neck and shoulder pain, and headache occur^1,3.

The prevalence of people around the world suffering from CVS ranges from 64% to 90%, and approximately 60 million people have been affected. In addition, 75% of people who spend more than 6 hours a day in front of a computer have a higher incidence of visual problems⁴. A report by the AAO indicates that each year, 10 million people go to a health center for eye examinations for visual problems related to the increased use of computers¹.

University students make up one of the groups most exposed to CVS after the group of office workers. One report indicates that approximately 81% of college students are affected by CVS; the widespread use of electronic devices for various academic activities explains this. Another study reveals that 89.9% of university students who use the computer for more than 2 hours a day suffer from CVS. This syndrome negatively impacts students' daily work, thus affecting productivity, efficiency, time management, general health, and well-being^4,5.

Therefore, the present investigation aims to determine the prevalence of computer vision syndrome in 6th-year medical students in a peruvian university in the context of virtual education due to covid-19.

Methods:

Results

Regarding the sociodemographic characteristics, we found that most students were young adults (54%) and females (60%). Most wore glasses (78%), both frame (75%) and contact (3%). The highest percentage of students spent more than 6 hours uninterrupted computer use (43%). Likewise, most spent less than two hours of uninterrupted cell phone use (27%). Regarding visual rest, most students rested at least every hour (29%), followed by rest at least every 2 hours (23%). Regarding the use of preventive measures, most of them did not take any preventive measure (44%), followed by those who kept their eyes closed for a while (27%), and finally, those who gazed at distant places (18%) (table 1).

Regarding any diagnosed visual disease, the majority reported having myopia (44%), followed by those with astigmatism (22%) and hyperopia (4%). Likewise, 27% did not present disease (table 2).

The students mainly presented tearing (7.9%), itching (7.6%), headache (7.6%), heavy eyelids (7.2%), and blurred vision (6.7%). Regarding the frequency of tearing, the students reported that they presented this symptom occasionally (51%), often or always (24%), and finally, never (25%). Regarding itching, the majority present this symptom occasionally (61%), never (28%), and often in a lower percentage (11%). Finally, regarding the headaches, the students presented them occasionally (50%), never 828%), and to a lesser extent often or always (22%) (table 3).

Regarding the intensity of the symptoms, tearing was mainly moderate (59%), mild (25%), and to a lesser extent, intense (16%). The itching was mainly moderate (54%), mild (28%), and less intense (18%). Headaches were mainly moderate (44%), mild (28%), and severe (28%). Regarding the frequency of CVS, it was found that 93% (136) of the students presented CVS. Regarding the relationship between the student's sex and CVS, this syndrome was more frequent in women, presenting CVS in 94% of them and 90% of men.

table 4studied the comorbidities associated with CVS, of which only preventive measures were associated (p=0.025).

Discussion:

The present study found that the frequency of computer vision syndrome was high, similar to that found in various studies in the population of medical students^7-10. However, other studies found a mean prevalence oscillating between 50%-60%^8,11. Likewise, at the national level, there is only one study on postgraduate students belonging to various faculties, resulting in a prevalence of 61%. The prevalence in students at the medical school level was 32.8%¹². In national studies on employees, a high prevalence was found related to workers with digital tasks^13,14. It should be noted that, due to the increasing use of information computer technologies (ICTS) in academic and work tasks, computer vision syndrome could be considered a public health problem, taking into account the reference of its prevalence at the national level and worldwide and still the ignorance of the approach and impact of this problem.

Likewise, it was found that women have a higher frequency of CVS than men. This coincides with studies reported on medical students, in which it was observed that females had a higher risk of developing CVS than males^7,8. This may be due to hormonal factors, in which women may be more predisposed to developing dry eye¹⁵, as well as other external factors. On the other hand, at the national level, no significant difference has been found in the prevalence in both sexes¹². Therefore, more studies would be needed to determine if, in reality, there is a significant variation in the prevalence of CVS in terms of gender and perhaps also considering the type of occupation.

Among the most frequent symptoms of computer vision syndrome in the students who were part of our population, tearing was observed with the highest percentage of responses (7.9%). This is similar to the finding in the study by Ghufran et al., where excessive tearing was the predominant ocular symptom (20.6%)⁷. In the present work, tied for second place we found itchy eyes and headaches (7.6% of responses for both), the latter symptom being the most frequent in other studies such as that of Altalhi a et al.⁹and Iqbal et al.¹⁰(68% and 50.2% respectively), differing from our results. Itchy eyes were found to be the third most prevalent symptom (63%) in the study by Altalhi a et al.⁹; however, it is not described among the most frequent symptoms in others. In our study, heavy eyelids ( 7.2%) ranked third, a symptom not evidenced in previous works. However, in the study by Vikanaswari, Gi & Handayani, a.¹²they mention tense or tired eyes as the most frequent (72.8%). In addition, unlike our study, other works agree that neck pain is the most characteristic symptom of computer vision syndrome^7,12. In this sense, a degree of variability is observed in relation to the report of symptoms most representative of this syndrome in the people suffering from it.

Another finding is the higher prevalence of CVS in those medical students who use a computer/laptop for more than 6 hours compared to those with only a few hours of exposure. This coincides with other studies carried out amongst medical students in which a significant correlation is found, the longer the hours of consumption (greater than 4 to 6 hours approximately) of digital devices, the greater the risk of presenting symptoms of CVS, and the one that occurs with the most frequent is myopia^16-18. On the other hand, two previous studies were presented, the first being carried out in Jamaica and the second in Saudi Arabia, both with a sample similar to this present work. Both did not find a significant relationship between the presence of CVS symptoms and the time the participants spent in front of the computer/laptop^4,19. This discrepancy may be due to factors specific to the sample or the methodology. However, a significant association between exposure time and suffering from CVS symptoms is explained by the fact that the longer the time spent on a laptop screen, the frequency of blinking decreases, and the production of the tear film decreases, which leads to its vaporization and causes symptoms associated with CVS.

Regarding the use of preventive measures against CVS, at least 41% of the students did not take any preventive measures, which is reflected in the study by Mendoza et al., where 59% of the population studied did not take preventive measures during the use of electronic devices, considering it a significant risk factor for developing CVS²⁰.

On the other hand, within the preventive measures against CVS, the techniques most used by students were: keeping their eyes closed for a specific time and trying to fix their gaze on distant sites, with 28% and 18%, respectively. These results are consistent with various national and international studies where students opt to use these measures to help relax muscles and provide a change in eye focus, preventing eye fatigue ^(5,13,21. Although, in the present study, around 10% stated the use of artificial tears as a preventive measure, studies such as the one by wang et al.²consider the use of these agents as a symptomatic treatment to reduce the effects of dry eyes in CVS, but not as preventive measures per se.

Regarding the use of preventive measures, this factor was found to be associated with SVI (p=0.025), where 44% of the students did not take any preventive measure. Similarly, in the study by Mendoza et al., 59% of the study population did not take preventive measures while using electronic devices either.

Among the study's limitations is its methodology; the cross-sectional information collection does not allow for determining causal inferences. Likewise, the collection of information virtually could generate a selection bias, where only those 6th-year students with internet access were able to participate in the study. Likewise, as it is a virtual questionnaire, the resolution of possible doubts of the participant concerning the questions of the questionnaire is limited, which could generate an information bias.

Conclusion:

In conclusion, a high frequency of CVS was found amongst 6th-year students of the faculty of human medicine, which showed a higher percentage of women being affected. Therefore, it is recommended to educate medical students on the use of preventive measures to avoid CVS, such as taking breaks of approximately 5 minutes every hour and placing the computer/laptop screen at a distance between 50 and 60 cm, among others, during virtual classes.