Since 2019, with the spread of the coronavirus and the emergence of new strains around the world, the effects of this virus on various organs of the body have been identified through various studies. According to these studies, the coronavirus has the ability to be transmitted through mucosal membranes, including respiratory membranes such as the nasal and conjunctival membranes. As the eyes are connected to the nasal duct through the inferior meatus, it is possible for the virus to be transmitted through this route. Wearing a mask can reduce the chance of transmission, but it can also lead to eye symptoms such as dryness. Additionally, individuals with COVID-19 experience various symptoms in their body systems. Some of these symptoms can affect the visual system and lead to blurry vision, dry eyes, foreign body sensation, tearing, and more. These symptoms can cause early eye fatigue and reduce the quality of academic and occupational performance. Since there is limited research in this area and considering the importance of this disease and its consequences, we decided to conduct an observational study on a number of COVID-19 patients referred to the clinic.
Research Article
Epidemiologic Investigation of Eye Symptoms Related to COVID-19 among Outpatient Population
https://doi.org/10.21203/rs.3.rs-3011231/v1
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COVID-19
Dry eye
infection disease
pandemic effects
Electronic device
Since 2019, following the global outbreak of the Covid-19 pandemic, experts and researchers have been investigating the various effects of this disease on the human body (1). Among these effects, one notable concern is its impact on ocular symptoms and dry eyes. The ocular mucosal immune system comprises the conjunctiva, cornea, lacrimal glands, and lacrimal ducts, which work together to distribute tears on the surface of the eye, preventing dry eyes (2, 3). These tears are eventually drained through the nasal lacrimal duct into the lower nasal meatus (4). It has been hypothesized that if respiratory droplets infected with the coronavirus come into contact with the eyes, they may enter the tears and subsequently reach the lungs and respiratory system through the nasal pathway (5).The presence of viral load in the tears of patients with various respiratory diseases, particularly in animal samples, supports this theory(6). The 2003 SARS virus epidemic, which belongs to the coronavirus family, demonstrated that direct or indirect contact between viral particles and mucous membranes such as the eyes, nose, and mouth can facilitate virus transmission (7). The eye can serve as an entry point for the virus both through exogenous means via the ACE2 receptor and through the endogenous route via the nasolacrimal duct (8). A study conducted in China in 2019 on 38 individuals with Covid-19 identified 12 patients with eye symptoms and 2 patients with positive conjunctival swab tests. These patients exhibited symptoms such as conjunctival hyperemia, tearing, and increased ocular discharge (9). Dry eye, resulting from impaired tear homeostasis, can have detrimental effects on an individual's quality of life and performance. As the severity of dry eye symptoms increases, individuals may experience reduced reading ability and blurred vision due to tear defects and their impact on the irregular function of the corneal epithelium (10). Notably, Covid-19 cases have been reported to involve retinal vessels (11) or cause blockages in central vessels and their branches, leading to eye hemorrhages (12). Studies have revealed that any delays in the necessary ocular processes in these patients, particularly among the elderly, may result in vision impairment or irreversible blindness (13). The use of face masks is one of the contributing factors that can lead to dry eyes. During exhalation, air is expelled from the upper part of the mouth, causing air circulation around the eyes, which can lead to itching, irritability, and dryness (14). In order to address several questions related to this matter, such as the nature of eye symptoms associated with Covid-19, the clinical characteristics of Covid patients with conjunctival involvement, and the potential transmission of the coronavirus through the eyes, it is crucial to conduct screenings among individuals affected by Covid-19 (15). Considering the limited number of studies conducted in this field and recognizing the significance of this disease and its complications, we have undertaken an observational study on a cohort of Covid-19 patients who have sought medical attention at our clinic.
The aim of this study was to investigate the ocular symptoms and treatments in outpatients with mild to moderate COVID-19 at Vali-e-asr Clinic in Hamadan City. The study is cross-sectional and was conducted from April 2021 until the required sample size was achieved. Patients were selected using an available not probability, sampling method.
2.1. Eligibility criteria
over 10 years old with a definitive diagnosis of COVID-19 based on PCR test results and the ability to answer questions were included to the study. patients, patients with severe COVID-19, mental problems, a history of eye problems before contracting COVID-19, and the use of contact lenses were excluded from the study.
2.2. Sample calculation method
Considering the study conducted by Boccardo et al. (16) in 2021, which investigated the prevalence of ocular symptoms in COVID-19 patients and reported it as 68%, with a 95% confidence interval and a margin of error equal to 0.08, the sample size was calculated using the following formula. A sample size of 130 was obtained.
2.3. Data collection tools
A researcher-made checklist was used to collect data, which included demographic information such as age, gender, and occupation of patients, ocular symptoms including burning, itching, foreign body sensation, blurred vision, eye pain, eye fatigue, etc., ocular treatments including medical and surgical treatments, information about the use of electronic devices such as mobile phones, tablets, laptops, televisions, computers, etc. Dry eye of the patient was also evaluated using the Schirmer test.
2.4. Statistical analysis
Data analysis was performed using descriptive statistics including frequency tables, percentage, mean, and standard deviation to describe the study population. Quantitative variables were reported as mean and standard deviation, and qualitative variables were reported as frequency and percentage. Statistical tests such as t-test, analysis of variance (ANOVA), chi-square test, and McNamar's test were used for data analysis. The results were reported at a significance level of 0.05. Stata software version 14 was used for data analysis.
A total of 130 patients, including 86 females (66.15%) and 44 males (33.85%), with an age range of 14 to 89 years and a mean age of 19.16 ± 11.42 years, participated in this study. The number of full-time employees or workers decreased considerably before COVID-19 (26.92% )and after COVID-19(13.84%). Additionally, the number of present university students affected by the pandemic significantly increased from 18.46% before COVID-19 to 26.92% after COVID-19. Conversely, the proportion of part-time employees or workers increased from 13.84% before COVID-19 to 26.92% after COVID-19. There were no significant changes in the number of unemployed individuals, housewives, and retired individuals. The percentages remained relatively stable before and after COVID-19 for these groups. It is worth noting that the statistical analyses conducted for these findings revealed significant differences in proportions (p < 0.001) for the changes observed in full-time employees, part-time employees, and university students affected by the pandemic. However, no significant changes were found for unemployed individuals, housewives, and retired individuals (p = 1.000 )(Table 1).
| Job | Before COVID-19 N (%) | After COVID-19 N (%) | p-value* |
|---|---|---|---|
| Full-time employees or workers | 35 (26.92%) | 18 (13.84%) | < 0.001 |
| Part-time employees or workers | 18 (13.84%) | 35 26.92%)) | < 0.001 |
| Unemployed | 8 (6.15%) | 8 (6.15%) | 1.000 |
| Housewives | 22 (16.92%) | 22 (16.92%) | 1.000 |
| Retired | 21 (16.15%) | 21 (16.15%) | 1.000 |
| Present university students | 24 (18.46%) | 5 (26.92%) | < 0.001 |
| Virtual university students | 2 (1.54%) | 21 (16.15%) | < 0.001 |
| Total | 130 | 130 | - |
| * Analyze using McNamar's test | |||
Regarding changes in performance after the pandemic started, 56 individuals (43.08%) stated that their performance had not changed, 19 individuals (14.62%) had increased performance, and 55 individuals (42.31%) had decreased performance. Regarding the diagnosis of dry eye, 16 individuals (31.12%) reported being diagnosed less than a year ago, 13 individuals (10%) one to two years ago, 26 individuals (20%) three to four years ago, 12 individuals (9.23%) four to five years ago, 10 individuals (7.69%) more than ten years ago, 38 individuals (29.23%) were unsure, and 15 individuals (11.54%) were never diagnosed with dry eye. Among the participants, 50 individuals (46.38%) had never visited medical centers for dry eye or its symptoms, 32 individuals (6.24%) had visited once, 22 individuals (16.92%) had visited two to three times, and 15 individuals (5.11%) had visited four to five times, while 11 individuals (8.46%) could not remember. After regarding changes in performance after the onset of the pandemic, 56 participants (43.08%) reported no change, 19 participants (14.62%) reported an increase, and 55 participants (42.31%) reported a decrease in their performance. Regarding dry eye diagnosis, 16 participants (31.12%) reported being diagnosed less than one year ago, 13 participants (10%) between one to two years ago, 26 participants (20%) three to four years ago, 12 participants (9.23%) four to five years ago, 10 participants (7.69%) more than ten years ago, 38 participants (29.23%) were unsure, and 15 participants (11.54%) were never diagnosed with dry eyes. Among the participants, 50 participants (46.38%) had never visited healthcare centers for dry eyes or its symptoms, 32 participants (6.24%) had visited once, 22 participants (92.16%) had visited two to three times, and 15 participants (5.41%) had visited four to five times, and 11 participants (8.46%) couldn't remember. Prior to the onset of the pandemic, mobile phones emerged as the prevailing device, as reported by 91.54% of the participants. Subsequently, during the pandemic, this prevalence experienced a slight upturn, reaching 95.35%. Nonetheless, the statistical analysis failed to achieve statistical significance (p = 0.4233) .The utilization of laptops exhibited a rise from 46.92% pre-pandemic to 55.38% during the pandemic. Despite this increase, the calculated p-value of 0.1020 indicates that the disparity lacked statistical significance. Likewise, there was a marginal increase in the utilization of televisions amidst the pandemic. Prior to the pandemic, 85.38% of the participants acknowledged employing televisions, while this proportion ascended to 92.30% during the pandemic. Nevertheless, the obtained p-value of 0.1951 suggests that the disparity was not statistically significant. Similarly, the usage patterns for tablets, computers, and engaging in reading or writing on paper experienced changes following the COVID-19 outbreak. However, the statistical analysis indicates that these alterations were not statistically significant. (Table 2)
| 3 | Before pandemic N (%) | During pandemic N (%) | P-Value |
|---|---|---|---|
| Mobile phone | 119 (91.54%) | 124 (95.35%) | 0.4233 |
| Laptop | 61 (46.92%) | 72 (55.38%) | 0.1020 |
| Television | 111 (85. 38%) | 120 (92.30%) | 0.1951 |
| Tablet | 57 (43.84%) | 68 (52.30%) | 0.1242 |
| Computer | 63 (48%) | 70 (53.84%) | 0.4723 |
| Read or wrote on paper | 92 (70.77%) | 98 (75.38%) | 0.4156 |
| * Analyze using chi-square test | |||
The results of our study showed that before covid-19 pandemic 25.38% of patients used them for less than one hour, 36.15% used them between one to five hours, and 30% used them between five to nine hours and after the COVID-19 pandemic, the majority of patients reported that 46.15% used them between five to nine hours and 29.23% used them for more than thirteen hours. The t-test analysis indicated that the mean difference in the time spent using electronic devices before and after the pandemic was statistically significant for all groups except for those who never used electronic devices. The p-values were all less than 0.001, except for the group that never used electronic devices, which had a p-value of 0.631. (Table 3).
| Time of using electronic devices | Before pandemic N (%) | During pandemic N (%) | P-Value |
|---|---|---|---|
| Less than 1 hour | 25.38% (33) | 8.46% (11) | 0.001 |
| 1 to 5 hours | 36.15% (47) | 15.38% (20) | 0.001 |
| 5 to 9 hours | 30% (39) | 46.15% (60) | 0.001 |
| More than 13 hours | 6.92% (9) | 29.23% (38) | 0.001 |
| Never Used | 1.54% (2) | 0.76% (1) | 0.631 |
| * Analyze using McNamar's test | |||
The findings from this study indicate a notable increase in various eye-related symptoms following the COVID-19 pandemic. Specifically, significant increases were observed in the prevalence of the following symptoms:Rapid blinking: The prevalence increased from 15.38–57.69%, indicating a significant change of 42.31%.Blurred vision: The prevalence increased from 31.54–68.46%, indicating a significant change of 36.92%. Additionally, significant increases were observed in the prevalence of tired eyes, foreign body sensation, eye irritation, and eye symptoms associated with electronic devices. These findings were statistically significant (p < 0.001), suggesting that these symptoms became more prevalent in individuals after the pandemic. However, the study did not find significant changes in the occurrence of eye pain, difficulty concentrating, and sensitivity to light between the pre-COVID-19 and post-COVID-19 periods. The p-values for these symptoms were not significant (p > 0.05), implying that the prevalence of these particular symptoms did not show substantial alterations following the pandemic. (Table 4).
| Symptom | Before COVID-19 N (%) | During COVID-19 N (%) | P-Value |
|---|---|---|---|
| Rapid blinking | 20(15.38 | 75(57.69%) | < 0.001 |
| Blurred vision | 41(31.54%) | 89(68.46%) | < 0.001 |
| Tired eyes | 34(26.15%) | 76(58.46%) | < 0.001 |
| Foreign body | 36(27.69%) | 69(53.07%) | < 0.001 |
| Eye irritation | 36 (27.69%) | 66(50.76%) | < 0.001 |
| Eye symptoms associated with electronic devices | 13(10%) | 42(36.92%) | < 0.001 |
| Headache due to eye symptoms | 18(13.84%) | 46(35.38%) | 0.001 |
| Hard to keep eyes open | 15(11.54%) | 37(28.46%) | 0.001 |
| Need to raise screen or room light while reading | 16(12.30%) | 43(33.08) | 0.002 |
| Tearing | 23(17.69% | 48(36.92%) | 0.002 |
| Fluctuating vision | 18(13.84%) | 43(33.08%) | 0.004 |
| Eye itching | 15(11.53%) | 35(26.92%) | 0.007 |
| Eye redness | 17(13.07%) | 32(24.61%) | 0.070 |
| Difficulty concentrating due to eye symptoms | 9(6.92%) | 18(13.85%) | 0.089 |
| Sensitivity to light | 5(3.84%) | 12(9.23%) | 0.245 |
| Need to increase text size while reading | 19(14.62% | 26(20%) | 0.261 |
| Eye pain | 47(36.15% | 50(38.46%) | 0.739 |
* Analyze using McNamar's test
Of the participants, 58 (44.62%) reported being diagnosed with dry eye or having received treatment for it, while 60 (46.15%) reported never having been diagnosed with it, and 12 (9.23%) could not remember. 21 (16.15%) reported having Sjogren's syndrome, while 100 (76.92%) reported not having it, and 9 (6.92%) were not sure. Participants were also asked if the severity of their eye symptoms changed before and after the pandemic. 19 (14.64%) reported that their symptoms became a little better, while 8 (6.15%) reported that their symptoms became much better. 23 (17.69%) reported that their symptoms did not change, while 33 (25.38%) reported that their symptoms became a little worse, and 47 (36.15%) reported that their symptoms became much worse. Regarding their vision changes, 12 (9.23%) reported that their vision had improved, while 42 (32.31%) reported that their vision had not changed, and 76 (58.46%) reported that their vision had worsened in the second stage compared to the first stage. For participants who started treatment for dry eyes, 1 (35.38%) used over-the-counter products, while 46 (35.38%) used prescription products. 5 (3.85%) used cold or warm compresses, 11 (8.46%) used eye glasses, 2 (1.54%) used contact lenses, 2 (1.54%) received treatment in a clinic or hospital, and 18 (13.85%) never used any treatment. Finally, participants were asked if they got better after treatment or not. 65 (50%) reported getting better, while 65 (50%) reported not getting better.
The present study provides insights into the impact of COVID-19 on individuals' employment status, performance, use of electronic devices, and dry eye diagnosis. The study findings indicate that the pandemic had a significant impact on the employment status of individuals, particularly on full-time and part-time employees or workers, as well as university students. The proportion of full-time employees or workers decreased significantly, while the proportion of part-time employees or workers increased significantly after the onset of the pandemic. Moreover, a significant increase in the proportion of university students who reported being affected by the pandemic was observed. Regarding performance, a significant number of participants reported a decrease in their performance after the pandemic started. In the study conducted by Liao X et al., similar to our study, it was observed that after COVID-19 infection, the post-COVID-19 group experienced a significant worsening of dry eye symptoms. The study found a reduction in lipid layer thickness (LLT-average and LLT-max), along with an exacerbation of Meiboscore in the upper and lower eyelids, and an increase in papillae. These findings collectively indicate a deterioration in dry eye parameters following COVID-19 infection (17). A meta-analysis study conducted by Nasiri et al., which included 1,021 COVID-19 patients, found that 138 patients experienced dry eye or foreign body sensation (18). This finding aligns with the data from our own study. Our study not only confirms the presence of dry eye symptoms in COVID-19 patients but also provides insights into the prevalence of dry eye and the frequency of healthcare visits related to this condition. Interestingly, a significant number of participants in the study had never received a diagnosis of dry eye, while a considerable proportion expressed uncertainty about their condition. Moreover, a large percentage of participants had not sought medical attention for their dry eye symptoms, suggesting a potential lack of awareness or concern regarding the condition. These findings underscore the significance of our study's results and indicate that dry eye symptoms are not limited to our specific population but also manifest in individuals with COVID-19. Furthermore, they highlight the need to increase awareness about dry eye, as a considerable proportion of individuals may remain undiagnosed or choose not to seek medical help for their symptoms. The study also investigated the use of electronic devices before and after the pandemic. The findings show that there were significant differences in the use of mobile phones, tablets, and laptops after the onset of the pandemic, indicating a shift in the use of electronic devices due to changes in lifestyle and work patterns. However, there were no significant differences in the use of computers and televisions before and after the pandemic. Both Saldanha et al. (2021) and our study reported a significant increase in the use of electronic devices during the COVID-19 pandemic, likely due to remote work and virtual communication (10). In the study conducted by Neti N et al., similar to our study, it was observed that the mean daily usage of visual display terminals (VDTs) significantly increased from 10.55 ± 5.16 to 13.08 ± 5.65 hours (P < 0.001). The study found that excessive exposure to VDTs was associated with worsened dry-eye symptoms and potentially contributed to the increased incidence of dry eye disease (DED) in the surveyed population (18). In the study conducted by Nasiri et al., the most commonly reported signs and symptoms in the patients were foreign body sensation, redness, tearing, and itching. However, when comparing these findings to our study, there are some differences in the prevalence of symptoms. Our study identified blurred vision, tired eyes, and rapid blinking as the most prevalent signs and symptoms (19). Interestingly, both studies highlight foreign body sensation as a commonly experienced symptom. This shared symptom suggests a commonality in the presentation of eye-related issues among the populations studied (19). On the other hand, the Nasiri et al. study reported lower frequencies for symptoms such as irritation, photophobia, and eye pain compared to our study. In contrast, our study identified eye pain and eye irritation, indicating some similarity in the results(19).In comparison to the study by Chen et al. (2020) that conducted a cross-sectional descriptive study in Wuhan, China, our study found a higher percentage of eye pain, tearing, foreign body sensation, and itchy eyes in patients with conjunctival symptoms (15). This significant difference between the two studies may be attributed to the pre-existing dry eye in some of our participants, which was not considered in the Chen study. Additionally, the mean age in our study was significantly lower than in Chen's study, which may have affected our participants' eye symptoms after COVID-19 due to increased use of electronic devices for telecommuting and online learning. In both studies, participants experienced various eye symptoms, such as eye pain, headaches, difficulty concentrating, and dryness, which can be attributed to increased screen time and stress related to the pandemic. Also, in Saldanha et al. (2021), respondents with moderate to severe dry eye were more likely to report eye symptoms and loss of access to dry eye-related treatments during the pandemic (10). In our study, significant increases in various eye symptoms, including blurred vision, fluctuating vision, the need to increase text size while reading, and eye irritation, were reported. Overall, the three studies indicate that the COVID-19 pandemic has had a significant impact on eye health. Overall, the three studies suggest that the COVID-19 pandemic has led to increased symptoms of dry eye and eye strain, likely due to increased screen time and other related factors.
Based on our study on the impact of COVID-19 on dry eye, we have found a significant increase in dry eye symptoms among patients with a history of COVID-19 infection. This increase in symptoms can be attributed to factors such as increased screen time due to telecommuting and online learning, as well as changes in employment status and job forms. Our study also demonstrated that the pandemic has had a significant impact on the employment status of individuals, particularly full-time and part-time employees, and students of school and university students. These findings highlight the potential long-term complications of the pandemic that should be further investigated and addressed. It is essential to raise awareness among individuals, healthcare professionals, and policymakers about the possible consequences of the pandemic on eye health and to implement appropriate measures to mitigate these effects.
6.1. Ethics approval and consent to participate:
This study was approved by the Research Ethics Committees of Hamadan University of Medical Science, with the ethics code IR.UMSHA.REC.1401.913. Informed consent was obtained from all participating patients or their legal guardians in this study after fully explaining the study methods other necessary matters. The study was fully explained to the patients, and all their questions and doubts were addressed. It was also emphasized to the patients that they could withdraw from the study at any time without affecting their treatment. All patients were assured that their personal information would remain confidential and that only collective information from the entire study would be available. Finally, all methods were carried out in accordance with relevant guidelines and regulations.
6.2. Consent for publication
Not applicable.
6.3. Availability of data and materials
All data generated or analyzed during this study are included in this published article.
6.4. Competing interests:
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
6.5. Funding:
This study was supported by internal funding. All authors read and approved the final manuscript.
6.6. Authors'Contributors
F.Eslami: Scientific consultant and study designer
S.Khazaei: statistical consultant and Data analysis
A.Eslami-Ghayour: wrote the manuscript text , Data collection and responding to patients
T.Mohammadi: wrote the proposal
6.7. Acknowledgements
We extend heartfelt appreciation to all those who have provided their unwavering support during our study.
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No competing interests reported.