Influence of Covid Pandemic on the Prevalence of Myopia in Urban School Going Children - Experiences of a Survey Study

Introduction

Myopia, known as short-sightedness or near-sightedness in common language is a state of refraction in which parallel rays of light coming from infinity are focused in front of retina, while accommodation is at rest. This causes distant objects to blur while the closer objects seem to be normal. Many environmental factors are implicated as risk factors in myopia such as excessive near work, less sunlight exposure, lack of physical activity, diet, a higher level of education, and urbanization.¹ Among these, excessive near work in the form of reading, screen time exposure and less outdoor time are well known life style risk factors of myopia. Ayurveda too implicates Sukshma Nireekshana (near work/looking at too small things) and Darshanena Bhaswaranam (exposure to glare and looking at shiny things) in causation of eye disorders.^2,3 Many studies have found that spending time outdoors has a negative or protective association with myopia. A meta-analysis summarizing the published reports on the association of outdoor time and myopia in population under 20 years of age confirmed that the time spent outdoors reduces the risk of developing myopia and there are 2% reduced odds of myopia for each additional hour spent outdoors per week.⁴ The onset of Covid pandemic brought drastic changes in education system in India, which turned completely online overnight and remained so for more than two years. The screen time increased many folds for all the children while the outdoor activities came to a standstill exposing the children to two well known risk factors of myopia, more so in urban school children. A bleak picture presented by World Health Organization estimating that half of the population of the world may be myopic by 2050, necessitates exploration of the impact caused by changed environment during Corona pandemic on myopia prevalence in children, so that measures can be taken to improve eye health in children.⁵

Materials and Methods

Aims and Objectives

This study aimed to investigate the prevalence of myopia among school children and compare it with pre-pandemic prevalence to assess influence of excessive screen exposure and less outdoor time among the urban school going children.

Inclusion and Exclusion Criteria

It was a survey study where 408 students in the age group of 5 to 16 years from four schools in Bangalore Urban, who were taking online classes since the emergence of Covid pandemic (April 2020) and who had fair knowledge of English language were selected irrespective of sex and religion. Children having history of eye trauma, eye surgery or any associated life threatening medical or surgical disorders were excluded.

Ethical Considerations

Approval for the study was obtained from the Institutional Ethics Committee (Certificate number: RES/SAMC & H-IEC/09/2021) before the commencement of the study. Written informed consent from the parents and assent from the children was taken on a bilingual English/ Kannada form. The identity of the subjects was kept confidential at every step.

Sample Size Calculation: A sample size (n) of 384 was decided using Krejcie and Morgan Table for sample size determination.[6] However, expecting a dropout rate of 5% a revised sample size of 404 was calculated using the formula N1 = n/ (1-d), where N1 is revised sample size and d is drop-out rate (.05) Finally, a total 408 children were enrolled for the study.

The data collection started on 29/11/2021 and was completed on 13/05/2022. All the data was entered in Excel sheet for ease of statistical analysis. A demographic questionnaire was administered for each student to gather information about their gender, age, grade, family composition. Myopia Risk Factor Questionnaire which uses five domains, Near work, Family history, Socioeconomic status, Outdoor activities and Diet, was used for collecting the data.⁶ Along with this, an eye health assessment questionnaire was used to collect the information about eye health. This consisted general questions about eye health, power of eyes, and increase in power during Covid pandemic.

Results

In this study, total 408 students in the age group of 5-16 years from four different schools of Bangalore Urban were enrolled. Among these, 217 (53%) were females and 191 (47%) were males and majority (92.89%) belonged to middle income group. Most of students were from 7th grade and above, and were having continuous online classes after the imposition of lockdown due to emergence of Covid pandemic in India (since around June 2020). Total 353 students were having online classes for more than five hours. The impact of Covid pandemic on exposure to digital media was apparent. Almost 92% of the students had access to mobile phones, 52% had access to computers and laptops. Around 77% of the students had access to internet. Only 5.88% were not using any other gadgets, while rest of them were using different types of gadgets for a duration ranging from one hour to 12 hours. Among all, around 26% of the students were having additional classes on digital media ranging from 40 minutes to six hours over the week days. The duration varied between 1-3 hours for most of the children but two among them were having 5-6 hours of weekday online classes. Also, around 102 students (25%) were having weekend extra online classes with the duration ranging from 1-3 hours. Three students were having 4, 5-and 7-hours weekend online classes, respectively. Additionally, most of the enrolled students (98%) had minimum one hour of homework involving screen exposure every day.

It was evident from this survey that high exposure to digital media was putting too much strain on the eyes. Around 20% (81) children reported having tiredness/ heaviness in the eyes, while 13% reported tearing after long hours of screen time (Table 1).

Significant number of students (144 students) reported frequent headaches while a few (14.46%) complained of burning sensation in eyes after classes. Around 15.2% parents showed their concern that child gets frequent attacks of headaches. Itching and irritation was present in 24% of students while redness in eyes was reported by 65 students. Very few children (2.7%) had frequent eye infections during that time (Figure 1).

Many parents (50.49%) were concerned about excessive use of phone by children. Almost 31% were concerned that the child keeps the face very close to screen while reading. More than half of the students (267) were maintaining less than adequate distance from screen. Only 160 students were keeping a distance of more than 10 feet from the TV screen while watching TV.

This study showed that changed circumstances such as lockdown might have had impacted the outdoor time of the children. On a normal routine day, around 21% children did not play out at all, while around 46% played for the duration of one hour or less. Only 36 (9%) children reported an outdoor play time of three hours or more. This worrying trend of less outdoor play was evident even during holidays as 30% of the children played outdoors for less than one hour, while 22% played for two hours only despite having school holidays. The study found that 22.79% urban school going children in the age group of 5-16 years were suffering from Myopia. Familial predisposition of refractive errors was apparent. Among 93 children with myopia, fathers of 37.6% and mothers of 18.27% had refractive errors. Paternal grandparents of 59% of the children had refractive errors, while maternal grandparents of 42% myopic children had history of refractive errors. Also, 18.27% myopic children had a sibling with refractive error. While in non-myopic children, family history of refractive errors was much less. Only 25.71% non-myopic children had fathers with refractive errors, 14.60% had mothers with refractive errors, 51% had paternal grandparents with refractive errors, 41% had maternal grandparents with refractive errors and 11.42% had siblings with refractive errors. The number of participants developed myopia after Covid pandemic were 11 and suspected were 48 (Table 2). 

Discussion

The overall crude prevalence of myopia over the last four decades in India is about 7.5% in 5-15-year age group. A meta-analysis of published literature of last four decades from 1980 to March 2020 (before lockdown) in the age groups from 5-15 years in urban or rural populations, covering nearly 1,66,000 urban and 1,20,000 rural children in 5-15-year age group found 8.5% prevalence in urban and 6.1% in rural children, with highest prevalence in urban 11-15-year age group [15.0% in last decade].⁷ The reported prevalence in Indian Urban schools in various previous studies was 4%, 4.4%, 13.1%, and 7.61%, respectively.^8-11 Our survey revealed high prevalence of myopia even before the onset of Covid pandemic in comparison to previously reported myopia prevalence in Urban school children in Bangalore. This study found prevalence of myopia in Urban Bangalore school children as 22.79%. Among the 408 students, 315 (77.21%) had no refractive error while 93 students were suffering with myopia. Among those having myopia, 11.8% developed myopia during the Covid pandemic while 82 students were myopic before the onset of Covid pandemic. There was an increment of 3.37% in confirmed cases and 14.72% in suspected cases of myopia after pandemic ended. Among 82 students who were myopic before the onset of pandemic, 45 (48.38%) reported increase in eye power during pandemic. Out of 326 non-myopic children, total 59 students developed myopia symptoms such as blurred distance vision, squeezing the eyes to see things at distance, eye strain, after the onset of Covid pandemic. However, due to pandemic related problems such as lockdown, fear or hesitancy to visit hospitals due to pandemic and non-availability of routine OPD services, 48 students among these 59 students could not visit an ophthalmologist. These 48 cases were taken as suspected cases of myopia and were taught eye exercises, were educated about lifestyle changes and advised to visit ophthalmologist at the earliest.

This study also showed that carbohydrate consumption was more common than protein-based diets such as legumes, eggs, meats, etc. However, diet pattern of myopic children was not ascertained on this study.

Limitations of the study

Due to limited resources and adherence to strict social distancing, the ophthalmologic examination of enrolled participants was not done. As it was a questionnaire based survey, reporting bias may be present in the collected data. Also follow up of the suspected cases of myopia was not done after the completion of study.

Conclusion

The present study established around 22.79% prevalence of myopia among urban school children in Bangalore. Similar studies conducted in Urban Bangalore before Covid pandemic reported lesser myopia prevalence in this age group, pointing towards lifestyle changes due to Covid pandemic having an adverse impact on the eye health of school children, resulting in increase in myopia prevalence.

Conflict of Interest

None

Funding

Funded by Rajiv Gandhi University of Medical Sciences

Acknowledgement

All schools who permitted to conduct the survey.