Malamulele Private School
Meri Thilmony
Copyright: 2022. The Author(s). Licensee: AOSIS.This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution,and reproduction in any medium, provided the original work is properly cited.
Background: Myopia is the most common cause of refractive errors in both adults and children in many countries. However, it is not a simple refractive error but sometimes an eyesight-threatening disorder. The disorder has a great impact on public health and the socio-economic well-being of people, particularly children.
Conclusion: Spending more time indoor and continuous reading without resting are risk factors of myopia whilst increased outdoor activities were observed as protective environmental factors against myopia in secondary school learners. Doing more outdoors activities may be beneficial to protect against myopia onset.
Socioeconomic status and lifestyle are reported to be the possible causes of the increasing myopia prevalence. Studies indicate that increased near-work activities, such as excessive viewing of television, excessive reading and playing video games that children are exposed to, make them prone to reduced visual acuity.12,13 Although genetic factors play a role in the development of myopia, the rapid growth in prevalence is likely attributable to environmental and lifestyle factors. Previous studies suggested an association between myopia and near-work activities, such as studying, reading and screen time amongst children as reported by Holden et al.11 Many studies have confirmed that increasing the time spent outdoors reduces the risk of developing myopia and pooled information indicated a 2% reduced odds of myopia for each additional hour spent outdoors per week.14
It is agreed that there is a genetic and environmental interaction that is involved in myopia cases. Furthermore, Dong et al.,9 pointed out that the process and progression of myopia follow a typical pattern, with normal vision at a young age, starting around school age a myopic shift and rapid increase in myopia begins, which continues until late teenage years. High myopia is associated with significantly increased risks of retinal degeneration and detachment, open-angle glaucoma and cataracts at a younger age.15 However, these associated conditions have a significant lifetime risk of severe visual impairment, including blindness. As a result of the significant risks associated with the development of high myopia, paediatric ophthalmologists have been very interested in the prevention of myopic progression.
It is estimated that 225 000 people (both children and adults) in South Africa are blind.20 Furthermore, about 10.0% of children need refractive services and correction.21 In the urban areas, about 60.0% of the population residing in urban areas had access to eye healthcare, whilst only 30.0% of those in the rural areas had access to eye healthcare. The prevalence of myopia and hypermetropia amongst South African school children was found to be 4.0% and 2.6%, respectively.17 Therefore, special attention should be given to children of school-going age because refractive error begins at that age. In the Vhembe district, school screening by optometrists and ophthalmic nurses discovered that many children reach their high school level without having had an eye examination.22 Many of them reported experiencing difficulties taking notes from the board, especially when sitting in the middle row or at the back in class. The Integrated School Health Programme Fourth Draft (2012) stipulated that all children above 8 years should be screened during their time at school.23 Primary healthcare (PHC) nurses conduct daily screenings at primary schools, but high schools have never been screened as the Department of Health seems more concerned with primary school learners. As a result of the unavailability of a myopic prevalence study in the Vhembe District, we decided to investigate the prevalence and risk factors of myopia in the district.
The study was conducted in Malamulele under the Collins Chabane Local Municipality, which is one of the five local municipalities in the Vhembe District. The area is mostly rural. Of the 45 high schools about 43 of the high schools are public and only two are private. The Vhembe District is relatively poor in terms of resources compared with other districts within the province. This is because it is dominated by rural areas where most of the inhabitants are farm labourers and public service employees. School health services are conducted daily by the PHC nurses. The PHC covers primary schools and focuses on general health.
The target population of this study was high school learners from the Malamulele Circuit. The accessible population were all Grade 8 learners from high schools that fall under the selected circuit. Learners who were in the academic year 2018/2019 regular programme and who had been selected by the sampling procedure constituted the study population. The study involved both male and female Grade 8 learners. The study population included learners aged between 13 and 14 years from both public and private secondary schools. Learners were excluded if they were not in Grade 8.
To assure data quality, all the selected schools were visited in advance to seek permission and cooperation from the school governing body and the principals. An invitation to participate in the study was sent to parents or guardians of the recruited study participants, together with the consent forms and information sheets. A meeting between the school-governing body, teachers and parents was held before the survey, where the details of the study were clearly outlined. Participants were included only if their parents gave signed consent forms for an examination.
The ophthalmic examinations included distance visual acuity measurement with and without pinhole, non- cycloplegic retinoscopic refraction, subjective refraction, ocular alignment and motility evaluation. An ophthalmic nurse measured visual acuity for each eye using the Snellen E-chart hanging on the wall at a distance of 6 m in a well-lighted classroom. A line of optotypes is generally considered to have been read correctly when more than half of the optotypes presented have been read correctly on the chart. Visual acuity was repeated with a pinhole. Learners with uncorrected and presenting visual acuity of less than or equal to 6/12, whose vision improvement showed with pinhole were refracted by an optometrist using a streak retinoscope and trial lens. Non-cycloplegic retinoscopic refraction was performed in a darkened room by maintaining a 2/3 m distance from the examiner. For those with positive retinoscopic refraction, subjective refraction was performed using a standard refraction trial set and frame and eyeglasses were prescribed. All learners with visual acuity of less than or equal to 6/12 and whose visual acuity did not improve with pinhole were advised to have regular follow-up at a nearby eye care centre for further management. The principal investigators closely monitored the entire process of data collection.
Most of the study participants came from rural areas because the Vhembe district is mostly rural. Most secondary schools were also found in a rural area with few schools found in the urban area. Hung et al.32 reported similar findings of the study that was conducted in the rural area of Vietnam. This study found that myopia was most prevalent in students who come from urban areas and attend private schools as compared with students who come from a rural area and attend public schools. These results are similar to a recent study by Xie et al.,33 which found a higher prevalence of myopia in urban areas as compared with the rural areas. Ragot et al.28 also reported another study that disclosed that the prevalence of childhood myopia is lowest (6.9%) in the outer suburban region and highest (17.8%) in the inner-city region. The reason for the high prevalence of myopia in learners from the urban area might have been attributed to the high rise in technology and the increased usage of mobile phones, tablets, computers and televisions. Similarly, children in urban areas are involved more in indoor and near-work activities, such as higher usage of computers, smartphones and video games unlike children from rural areas as reported by Atowa et al.29 in their study. The findings from this study showed that myopic learners spent more time performing indoor activities such as reading and less time in outdoor activities than the non-myopic learners. Studies have confirmed that reduction in outdoor activities has been found to have some influence on the onset, development and progression of myopia.28,34
Regarding gender, the present study found that the prevalence of myopia was slightly higher in males than in females (Table 2), similar results were also reported by Ragot et al.28 who mentioned that myopia was slightly more (52.7%) prevalent in males as compared with females (47.3%). However, several studies reported a higher prevalence of myopia in females than in males.29,32,33 However, it differs from the study conducted in Welkite town (Ethiopia) and Shanghai (China) that revealed that sex had no association with the prevalence of myopia.25,35 The reason may be that the cause of myopia could be more hereditary in our study area. Other studies further confirmed that girls experienced more risk factors of developing myopia as compared with boys, the reason possibly being that girls study harder and participate less in outdoor activities than boys.32,36.
In this study, a high prevalence of myopia was associated with higher age and higher grade level, even though this study was only performed with Grade 8 learners. Also, the stage of puberty might be a major contributing factor to myopia development and progression in this study.
This study was consistent with the study findings conducted in Vietnam, Abia state (Nigeria) and Welkite town (Ethiopia), which reported a similar trend that the prevalence of myopia amongst school children tends to increase with age.25,32,33
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