Eyeglasses in the wonderland of COVID‐19

A recent cohort study1 at Suizhou in China identified that the proportion of subjects who wore eyeglasses was lower in hospitalized patients with coronavirus disease 2019 (COVID-19) than in the general population. The study, however, enrolled a small number of patients with COVID-19 (276 patients) including those with myopia (16 patients) in a single center. In the present study, the association of myopia with COVID-19 in US states was investigated applying inverse-variance weighted regression. For each US state, the cumulative number of COVID-19 confirmed cases, deaths, and tested subjects on September 20, 2020 were available on the “Johns Hopkins Coronavirus Resource Center (https://github.com/CSSEGISandData/COVID-19/blob/master/csse_covid_19_data/csse_covid_19_daily_reports_us/09-20-2020.csv).” Estimated prevalence rates (per Census 2010 populations) of myopia were procurable in the “Vision Problems in the United States, 2012 edition (http://www.visionproblemsus.org/vpus-search.html).” Cumulative incidence rates of COVID-19 were calculated as cumulative cases per populations in 2018 (available on the “2014–2018 ACS 5-Year Data Profile [https://www.census.gov/acs/www/data/data-tables-and-tools/data-profiles/2018/]”), test-positive rates were defined as cumulative cases per cumulative tested subjects, mortality rates were calculated as cumulative deaths per populations, and fatality rates were defined as cumulative deaths per cumulative cases. The random-effects inverse-variance weighted regression (i.e., meta-regression considering a state as a study in a meta-analysis) was performed using OpenMetaAnalyst (http://www.cebm.brown.edu/openmeta/index.html). In the inverse-variance weighted regression which is quite different from simple regression, association of explanatory variables with an outcome variable is more influenced by larger samples (states in the case of the present study) than by smaller samples because samples are weighted by the precision of their respective estimate (https://training.cochrane.org/handbook/current/chapter-10#section-10-11-4). A regression graph depicted COVID-19 cumulative incidence, test-positive, mortality, and fatality rates (plotted as the logarithm-transformed data on the y-axis) as a function of myopia prevalence rates (plotted on the x-axis). To adjust for potential confounders, the multivariable regression was performed when a coefficient of myopia prevalence was statistically significant (p < .05) in the univariable regression. The multivariable regression entered demographic and socioeconomic characteristics (including age and race distribution) (Table 1) together with myopia prevalence as covariates. In the entire United States, myopia prevalence was 23.92%, the COVID-19 cumulative incidence was 2093 cases per 0.1-million population, the test-positive rate was 7.14%, the mortality was 61.58 deaths per 0.1-million population, and the fatality was 2.94% (Table 1). The myopia prevalence was significantly and negatively associated with the COVID-19 incidence (coefficient [slope of the meta-regression line], –0.144 of logarithmic cases [per population] per 1% increase in myopia prevalence; 95% confidence interval [CI], –0.228 to –0.060; p < .001; Figure 1, upper panel), the test-positive rate (coefficient, –0.111 of logarithmic percent per 1% increase in myopia prevalence; 95% CI, –0.211 to –0.011; p = .030; Figure 1, lower panel), and mortality (coefficient, –0.204 of logarithmic percent per 1% increase in myopia prevalence; 95% CI, –0.324 to –0.083; p < .001; Figure 2, upper panel). Myopia prevalence, however, was not correlated to fatality (coefficient, –0.073 of logarithmic percent per 1% increase in myopia prevalence; 95% CI, –0.176 to 0.031; p = .169; Figure 2, lower panel). In multivariable regression, myopia prevalence was still significantly and negatively associated with the COVID-19 incidence and the test-positive rate, whereas it was not correlated to mortality (Table 2). Similar analyses were performed for hyperopia and cataract. The hyperopia prevalence was associated with none of the COVID-19 incidence (p = .065), test-positive rate (p = .543), mortality (p = .055), and fatality (p = .357). The cataract prevalence was also correlated to none of the COVID-19 incidence (p = .819), test-positive rate (p = .445), mortality (p = .712), and fatality (p = .672). The present study indicated the significant, independent, and negative association of the myopia prevalence with the COVID-19 cumulative incidence and the test-positive rate (neither the mortality nor the fatality) in US states, which suggests a probably negative correlation of wearing eyeglasses to COVID-19 infection because eyeglasses are the primary choice for optical correction in most myopia patients (https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/myopia?sso=y). Wider view fields and clearer vision, however, may be offered by contact lenses than eyeglasses for some subjects, and laser procedures (e.g., laser in situ keratomileusis or photorefractive keratectomy) are also potential options for adult myopia (https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/myopia?sso=y). According to the “Vision Council of America (https://www.thevisioncouncil.org),” 75% of adults need vision correction, and 64% and 11% of them wear eyeglasses and contact lenses, respectively. In accordance to “Jobson Optical Research (https://jobsonresearch.com),” 61% of the population in the United States use some sort of vision correction, and 61% of them need eyewear due to myopia. Due to the community-level (not patient-level) study design, the present findings simply denote that COVID-19 infection was less frequent in states where myopia patients (who probably wore eyeglasses) were more present, and never directly import that a myopia patient is at low risk of COVID-19 infection. Zeng et al.1 also suggested the association of wearing eyeglasses with less frequent COVID-19 infection. Similar to their study, which compared the proportion of COVID-19 patients who wore “eyeglasses” (all of them suffered “myopia”) with that of “myopia” patients (not subjects who wore “eyeglasses”) in the general population, the present study investigated the proportion of “myopia” patients (not subjects who wore “eyeglasses”) because of unavailable data on wearing “eyeglasses.” The sample size, however, was far greater in the present study (approximately 6.8-million COVID-19 patients and 34-million myopia ones in the entire United States) than in the study by Zeng et al.1 (merely 276 COVID-19 patients and 16 myopia ones at a city in China). Angiotensin-converting enzyme 2 (which is known as a SARS-CoV-2 receptor) has been identified in the human retinal as well as non-retinal ocular structure.2 One-third of COVID-19 patients suffered conjunctivitis (including conjunctival hyperemia, chemosis, epiphora, or increased secretion) which is more frequent in patients with more severe COVID-19.3 Eyeglasses may evade hand-to-eye transfer of the virus by means of restraint and dissuasion of feeling eyes.1 The “COVID-19 advice for the public” by the World Health Organization (WHO) (https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public) also recommends to avoid touching eyes. Several issues should be noted as limitations of the present study. First, although the myopia prevalence was provided in merely ≥40-year subjects, the COVID-19 cumulative incidence was reported in all-age subjects. Second, the myopia prevalence is 1.8-fold greater in Whites (26.4%) than in Blacks (14.5%) (http://www.visionproblemsus.org/vpus-search.html), whereas the COVID-19 incidence is 2.6-time higher in Blacks than in White (https://www.cdc.gov/coronavirus/2019-ncov/covid-data/investigations-discovery/hospitalization-death-by-race-ethnicity.html). Hence, in states with greater proportion of Whites, myopia prevalence and COVID-19 incidence would be higher and lower, respectively. Zeng et al,1 however, did not address these confounders. In the present study, the proportions of Black (or African American) and ≥35-year subjects (because of unavailable proportions of ≥40-year subjects) were entered into the multivariable regression as potential confounders, which indicated still a significant and negative association of the myopia prevalence with the COVID-19 incidence and the test-positive rate. Third, although the myopia prevalence in 2012 was calculated using the Census 2010 populations, COVID-19 incidence was defined using the populations in 2018 from the “2014–2018 ACS 5-Year Data Profile.” More recent data on myopia prevalence, however, have not been procurable to date. Fourth, as aforementioned, the proportion of “myopia” patients instead of subjects who wore “eyeglasses” was analyzed in the present study, which may bias the suggested negative association of wearing eyeglasses with COVID-19 infection. Finally, during the COVID-19 pandemic period, some people may have worn a face shield as a preventive behavior against COVID-19. The combination of a face mask and a face shield could crucially retard the COVID 19 spread.4 In conclusion, on the basis of data from US states, myopia prevalence was independently and negatively associated with the COVID-19 cumulative incidence and the test-positive rate (neither the mortality nor the fatality), which suggests that wearing eyeglasses may be negatively correlated to COVID-19 infection but doesn't import that a myopia patient is at low risk of COVID-19 infection.