There is a possibility that geographical and cultural variations might play a role in the development of refractive defects in children from middle-income households [1]. Refractive errors cause light to deviate from its intended path before reaching the retina, ultimately resulting in altered visual experiences [2, 3]. The structural properties of the eye primarily account for this deviation in eye alignment. Myopia, or nearsightedness, is among the basic categories of refractive abnormalities, alongside hyperopia (farsightedness), astigmatism, and presbyopia, which refers to age-related reductions in both near and farsightedness [4].

In comparison to nations with higher income levels, countries with intermediate incomes may offer a more limited range of healthcare services and fewer opportunities for eye examinations [1]. Children with refractive defects from middle-income homes are more likely to receive timely diagnosis and treatment due to increased access to healthcare services and resources [1, 2, 3, 4, 5], as people in middle-income families typically have more diverse healthcare alternatives available to them. Children from middle-class families may face a higher risk of developing refractive defects due to various factors. Some contributors to myopia in children and adolescents include genetic predisposition, excessive screen time, limited engagement in outdoor activities, increased academic pressures commonly found in middle-income households, inadequate access to eye care services, and insufficient nutrition [3, 4, 5].

Current research projects the global prevalence of visual impairment to be around 0.97 percent, with most cases concentrated in major cities of Southeast Asia and China, affecting 12.2 million children aged 5 to 15 [6]. According to studies, individuals with 20/40 or better vision in both eyes comprised 7.4% of the urban population and 4.9% of the rural population in India [7, 8]. The majority of these cases were associated with refractive defects, accounting for 81% in urban regions and 53% in rural areas, respectively [6, 7, 8].

Children born with untreated refractive abnormalities in countries with moderate incomes, such as India, continue to face significant challenges. Despite the availability of low-cost corrective techniques like eyeglasses, a considerable number of children in India experience vision issues due to uncorrected refractive defects [9, 10]. Refractive errors can impair a child’s visual acuity and create difficulties in performing daily tasks if proper corrective measures are not taken. Moreover, they might hinder their academic and professional development [11]. Untreated visual impairments in children may lead to difficulties in activities such as reading, writing, and participation in educational pursuits, ultimately affecting their academic achievements [8, 9, 10, 11]. In countries with moderate incomes, like India, where this issue is prevalent, barriers preventing access to eye care services are particularly common [7, 8]. Factors such as individuals’ low confidence in and understanding of the benefits associated with such services contribute to these challenges arising from their lack of awareness or difficulty in accessing ocular healthcare services [9, 10, 11]. Therefore, this research aims to investigate the prevalence of refractive errors among children from middle-class backgrounds.

The current investigation did not commence until after its creators secured approval from the Institution’s Ethics Committee. The research was conducted at Gautam Budha Chikitsa Mahavidyalaya, Jhajra, Dehradun, India. The participants comprised children from middle-income families residing in and around the Dehradun city area.

Families eligible for participation had annual incomes ranging from 5 million to 30 million rupees. Children aged between 5 and 15 were eligible; however, some individuals were granted permission while others were not. The primary focus of the study was to determine the geographical area or region, and notes were taken accordingly. The potential site could be a specific town, city, urban or suburban neighborhood, or even a broader area. It could also encompass one of several other geographical locations.

Individuals below the legal age of maturity, with their parents’ or legal guardians’ consent, were required to provide informed consent to participate in the study to comply with the law. Subsequently, the concept of ethics evolved, supported by parental consent. All participants had to demonstrate successful recent eye test results before engaging in the study. Individuals with cataracts, retinal diseases, or uncertainty about participation were excluded due to non-compliance with the criteria.

The language and communication abilities of both the participants and their legal guardians were considered before conducting the research. This ensured understanding and adherence to the study’s directions.

Work nature

The fieldwork was conducted between the years of 2019 & 2022 in a cluster-by-cluster fashion. Clinical evaluations and other fieldwork were often completed within a cluster and moved on to the next cluster within a week. This was done before moving on to the next cluster. Prior to counting the eligible children from one family to the next, each cluster was mapped by three field investigators so that all of the houses could be located and identified. Before beginning the mapping, the field investigators made contact with a prominent member of the community in order to brief them on the purpose of the survey and to ask for their assistance. In the past, the presence of family members who resided and had meals in the exact location was considered to characterize a house. Household heads (whether male or female) were informed of the study’s goals and methods during the enumeration. Name, age (in completed years), gender, number of years in school, and the name of the school attended were collected from each child aged 7 to 15. In addition, data was collected on the educational levels of the parents as well as the number of eligible children who were missing from the community. We reached out to our neighbors to inquire about the number of children eligible to participate in each home and their availability. This study did not include children who were either temporarily resident (for less than six months), institutionalized, or absent for at least six months.

Whoever was the primary caretaker of the eligible child receiving a card with the scheduled date for the eye exam? Children who need corrective lenses were asked to bring them to the exam. Following a discussion of the procedures involved in the eye test, during which it was mentioned that cycloplegic eye drops might cause a temporary blurring of vision, the adult residing in the home gave their signed informed permission for the eye exam. Before classifying someone as a nonparticipant in the study, at least three attempts were made to contact those who said no to participating in the investigation. Two of these attempts were made within the week the research team spent in the cluster, and the third attempt was made after the investigation. On the date that was given, the children were brought to the location where the examination would take place.

The examinations were performed at a clinic at the rural eye hospital established for the research. The clinic was staffed by two ophthalmic technicians with experience ranging from five to three years, respectively, and one ophthalmologist with prior experience ranging from four to five years. In most cases, examinations were carried out six days a week during the normal operating hours of the clinic. The procedures for inspecting have been extensively discussed in other places [7, 8, 9, 10].

Eye examination

Technicians in the field of ophthalmology commonly conduct various examinations. These include checking patients’ distance vision, assessing ocular motility, performing retinoscopy and autorefraction after cycloplegia, and conducting subjective refraction on patients with uncorrected visual acuity of 20/40 or below in either eye. To measure visual acuity at a distance of four meters, retro-illuminated log minimum angle of resolution (MAR) charts with five E optotypes on each line were employed. A reading with one or no errors on the shortest line was considered accurate.

For children wearing glasses, both presented visual acuity (with glasses) and uncorrected visual acuity (without glasses) were measured for both eyes. If the child wasn’t already wearing spectacles, the examination began with the left eye. The optical quality of the lenses was assessed using a lensometer.

Ocular motility was evaluated at distances of 0.5 and 4.0 meters. The severity of vertigo, esotropia, or exotropia could be determined by examining the corneal light reflex. Two drops of 1% cyclopentolate were instilled in each eye, allowing five minutes for pupil dilation. A third drop was administered if a pupillary light response persisted after 20 minutes. Full cycloplegia was defined when the pupil size was at least 6 mm with no light response after an additional 15 minutes.

Following cycloplegic refraction, children underwent streak retinoscopy for refraction, irrespective of their visual ability. A portable autorefractor (Matronix Q30+), calibrated daily, was used for cycloplegic autorefraction. Subjective refraction was conducted for children unable to achieve 20/40 or better vision in one eye without correction. This was also performed for adults.

Several considerations were made during the study:

1. Eye classifications based on visual acuity: normal or near-normal vision (\(20/32\) or better) in one or both eyes; unilateral visual impairment (20/32 or better) in one eye; mild visual impairment (\(20/40\) or better) in one eye; moderate visual impairment (\(20/80\) or better) in one eye; severe visual impairment/blindness (\(20/200\) or worse) in one eye; normal or near-normal vision (\(20/32\) or better) in both eyes.
2. Refractive error criteria: myopia or hypermetropia, based on cycloplegic autorefraction measurements. Emmetropic vision was defined as normal or almost normal eyesight, and children without significant myopia or hyperopia in either eye were classified as "emmetropic."
3. Myopia diagnosis: spherical equivalents (SE) of \(0.50D\) or greater. Children diagnosed with myopia could have one or both eyes affected by the condition.
4. Hypermetropia diagnosis: SE greater than \(+2.0D\). Children diagnosed with hyperopia had one or both eyes affected unless neither eye was myopic, in which case they were classified as hyperopic.
5. Astigmatism criteria: cylinder values between \(0.75\) and \(1.50\), \(1.50\) and \(2.00\), and \(= 2.00 D\).
6. Amblyopia determination: BCVA (best-corrected visual acuity) equal to or worse than \(20/40 (6/12)\) and no visible organic lesion. Amblyopia was diagnosed if the eye met specific conditions related to tropia, anisometropia, or bilateral ametropia.
7. Definition of uncorrected visual acuity for children without corrective lenses, regardless of whether they wear them.
8. Evaluation of current visual acuity with and without customary spectacles; if not worn, the assessment is conducted without corrective lenses.

Statistical analysis

In order to collect all of this information, we made use of a standardized questionnaire. The primary investigator tidied up and looked for flaws in the data while they were still out in the field collecting it. After another round of cleaning, two data entry clerks at the research office coded and double-entered the information that had been collected. The data cleaning program analyzed the measurement data, looking at the data’s ranges, frequencies, and internal consistency. All statistical computations were carried out using version 22 of SPSS, which was developed and distributed by SPSS Inc. in Chicago, Illinois, USA. Calculations were made using UCVA, presenting VA, and BCVA to determine the prevalence of blindness and poor vision. When conducting tests of statistical significance, the Chi-square statistic was applied to the percentage data wherever it was required. When estimating a disease’s prevalence, the probability significance at the < 0.05 level and the confidence intervals (CIs) to 95% were computed.

Over the course of the allotted time for the study, a total of 351 young people were investigated (Table 1). 44% of the people in this cohort identified as being male, whereas 56% of the people in this cohort identified as being female. The average age of the participants was found to be 9.98, with a standard deviation of 1.96 years. There were kids there as young as 5 and as elderly as 15 years old. Of the total number of persons who took part in the study, 83 were in the age range of 12-13, making up the largest single demographic. Table 1 displays data on the children’s demographic characteristics. A significant portion of the group was comprised of kids who lived in cities.

Table 2 shows what proportion of kids have uncorrected 20/32 or better vision in at least one eye. A total of 326 kids, or this proportion, were found to have it. A total of twenty-seven kids had vision impairment (classified as 20/40 or worse), and four of them were completely blind. Twenty-eight children, nineteen children, and two children had uncorrected visual acuity of 20/40 (6/12) or better. Two kids were found to have the finest corrected VA. Of the 48 kids who had to use glasses, 14 had double vision problems from not wearing them, and of the 27 kids who were legally blind without glasses, 14 used them. Best-corrected visual acuity testing allowed for 15 individuals with bilateral vision impairment to be eliminated from the sample.

Refractive error is the most common reason for impaired vision (Figure 1), and for good reason. In 24 eyes (12 right, 12 left), amblyopia that met the criteria indicated was the second most frequent cause of the condition. Regarding 16 of these eyes, we have no clue what may have gone wrong. It was assumed that refractive error existed in any kid who wore or did not wear corrective lenses, whose VA improved with pinhole, and who did not tolerate auto-refraction owing to unwillingness.

Figure 1: Primary Causes of Visual Impairment

According to Table 3, 3.4% of the general population, including both sexes and persons of all ages, have some refractive impairment. Today’s population shows a statistically significant (p 0.001) gender gap in the prevalence of refractive error. The prevalence of myopia was found to be 1.9%, whereas hypermetropia was found to be just 0.3%. Astigmatism of 0.75 diopters or more was found to be detrimental to the individuals’ ability to see in 71 (2.9% of the right eyes) and 82 (3.2% of the left eyes).

This study provides credible and comparative statistics on the prevalence of refractive error and visual impairment among children from middle-income families in the Dehradun region. This region has not been previously investigated in this manner. Consistent with similar research conducted in Hong Kong [12], women constituted a slight majority of respondents. Global initiatives to promote women’s and girls’ education, particularly in countries with poor or moderate incomes, may have contributed to this upward trend.

Uncorrected visual acuity was measured, revealing that 326 children had vision at or above 20/32. Twenty-seven youngsters, including four who were completely blind, had visual deficits of 20/40 or worse. Among them, 28 children had uncorrected VA of 20/40 (6/12), 19 had 20/40 (6/12), and 2 had 20/40 (6/12) even with the best correction. Forty-eight kids used glasses or other vision correction methods; notably, 14 out of 27 kids with double vision loss did not. The bilateral vision impairment level could potentially be reduced to 15 with the use of best-corrected visual acuity tests. Different studies have shown rates consistent with or different from our findings. Similar [13], higher [14], and lower [15] rates have been observed, potentially due to variations in genetic and environmental factors causing childhood blindness across different groups.

This study found a 1.9% prevalence of refractive error across sexes and age groups. Notably, 84% of students needing corrective lenses were from metropolitan campuses, constituting 84% of the total. Myopia was the most common refractive error, disproportionately affecting women, seventh graders, and urban children. India (4.9% lower), Chile (6.8% lower), and China (16.2% lower) have lower documented populations with these illnesses. Refractive error rates were notably higher in urban regions despite higher median incomes [17], which is crucial information for eye care practitioners aiming to prevent childhood blindness.

In contrast to India (0.78%), China (3.5%), and Chile (16.3%), the United States has a very low hyperopia prevalence of 0.1%. Astigmatism of 0.75 D or higher was found in 2% of children, similar to India (2.8%) and Nepal (2.2%). However, compared to China (15%) [16] and Chile (19%) [20], the gap widens significantly. Discrepancies may arise from diverse populations in urban, semi-urban, and rural areas. Environmental factors, like time spent outdoors, also influence myopia rates, with each additional hour outside reducing myopia rates by 2

Regarding eye dominance, 87.6% had an issue with their left eye, and 85.0% had refractive defects in their right eye. These findings align with RESC and non-RESC population surveys [12,14, 14, 19, 20, 21, 22, 23, 24], emphasizing the global importance of correcting refractive errors to reduce avoidable blindness. Amblyopia, accounting for 5.6% (right-eye) and 5.9% (left-eye) of visual impairment cases, follows refractive error as the most common cause. Early identification and corrective measures are essential preventive steps [20].

Most adolescents needing corrective eyewear don’t use it due to necessity, similar to findings in Brazil [20] and India [19]. Utilization of refractive services is low in economically challenged countries [12, 22, 23, 24], potentially limiting access to optimal eye care for socioeconomically vulnerable children.

Vision tests play a pivotal role in reducing visual impairment in youngsters [19]. Regular vision examinations by qualified specialists, accessible to all school-age children, are essential. Plans should be in place to provide necessary eyeglasses to those in need.

While the research’s strength lies in its sample size, limitations exist, notably the study’s school-based structure, which might not represent the broader community. Not all children in these areas attend school, potentially biasing the selection process. Moreover, children with significant visual impairments may not attend school, further affecting representation.

It was shown that among school-aged children in this area, refractive errors were the leading cause of visual impairment, especially among those from middle-income parents. Because of the detrimental effects that impaired vision may have on a child’s academic performance and overall growth, as well as the ease with which the majority of refractive errors can be corrected with glasses, measures must be taken to lessen the prevalence of impaired vision, which is also economical. The evidence points strongly to the fact that this readily curable source of blindness is responsible for the condition.

This research paper received no external funding.

The author declares no conflicts of interest.

Informed consent was obtained from all participates in the study as needed.

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