A cross-sectional study of types of refractive errors in school-going children aged 5–14 years

INTRODUCTION

India, the blind capital of the world, with 275 million people having vision loss, out of which 9.2 million are blind, 79 million have moderate to severe, 49.1 million have mild, and 137.7 million have near vision loss.^[1] An impairment of vision is defined as a patient having the best-corrected visual acuity of <6/18 in the better eye. Blindness is defined by the World Health Organization (WHO) as visual acuity <3/60 with the best possible correction in the better eye on the Snellen visual acuity chart.^[2] A refractive error is a very common eye condition which is defined as a state of refraction when the parallel rays of light coming from infinity (with accommodation at rest) are focused either in front or behind the sensitive layer of retina, in one or both meridian^[3] There are several types of refractive error: Myopia (short-sightedness or near-sightedness), hypermetropia (long-sightedness or farsightedness) and astigmatism (distorted vision resulting from irregular curvature of the cornea or lens of the eye resulting in difficulty in seeing distant and close objects clearly).^[4] Refractive errors are common visual impairments affecting millions of children worldwide.^[5] Uncorrected refractive error is the leading cause of blindness. Uncorrected refractive errors significantly impact a child’s ability to learn and perform in school, potentially influencing their overall development and quality of life.^[6] Increasing myopia prevalence (especially Urban >rural) also increases the significance of early diagnosis of visual impairment in school-going children.^[2,4,7-10] There is a need for implementation of effective prevention and management strategies, especially in school-age children, where early detection and intervention can mitigate future complications.^[11] The present study was conducted to determine the percentage of different types of refractive errors in school-going children aged 5–14 years, demographic variation of types of refractive error based on gender and geographical location and family history of refractive error as a risk factor for the development of refractive error.

MATERIALS AND METHODS

A hospital-based descriptive observational cross-sectional study was conducted at a tertiary eye care centre in Western India for 2 Months (July 2024 and August 2024) in 2024 after receiving approval from the Institutional Ethics Committee to determine the prevalence of types of refractive errors in school-going children. On average, the tertiary eye care centre attends to 120 children in the required age group in 1 month. Considering the dropout rate of 10–15% the sample size was selected as a total of 201 children. Detailed medical histories and records were taken from individual patients and were recorded in a pre-validated case record form (CRF). The following data were recorded: Demographic details such as name, age, gender, and address, detailed history including family history, refractive error correction, and provisional diagnosis. Convenience sampling was used. The data were analysed using the Jamovi 2.6.13 software. To verify the proportion, the Chi-square test of the independent variable was used. Statistical significance for these tests was defined as a P-value of 0.05 or lower.

The methods used to assess the patients’ refractive errors by the ophthalmologists at the tertiary eye care centre were Snellen Chart-visual acuity testing, Auto-refractor, Retinoscopy, and correction using a Trial frame. Optometrists assessed refractive errors. Paediatric ophthalmologists reviewed all cases for confirmation of findings and management planning. Cycloplegic refraction was performed with homatropine (0.5%), which was used in the age group of 5–7 years (correction factor = 0.75). For the age group of 7–14 years 1% cyclopentolate was used (correction factor = 0.5).

RESULTS

A total of 402 eyes were examined in 201 children. As shown in Table 1 and Figure 1, out of 402 eyes examined, the frequency of Simple Myopia was 28.61%, Simple myopic astigmatism was 11.94%, compound myopic astigmatism was 40.05%, simple hypermetropia was 3.73%, simple hypermetropic astigmatism was 5.47%, compound hypermetropic astigmatism was 4.48%, and mixed astigmatism was 3.98%. Out of 402 eyes examined, 7 eyes do not have any refractive errors, which constituted 1.74% of the total eyes. As shown in Table 2, the P value is significant in age, location and family history but is insignificant in gender. The prevalence is higher in the Central Zone of Ahmedabad and among the 9–12 age group. In our study, we found that compound myopic astigmatism is more prevalent, and the following mean values were observed [Table 3]. The analysis of refractive errors for the right and left eyes shows that the right eye has a mean spherical equivalent of −4.202 D with a standard deviation of ± 2.610 D, while the left eye has a mean of −4.239 D and a standard deviation of ±2.775 D. When combining the data from both eyes, the overall mean spherical equivalent is −4.221 D, accompanied by a standard deviation of ±2.684 D. This indicates that both eyes exhibit moderate to high myopia, with some variability in refractive errors, particularly in the left eye.

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Figure 1:

Pie chart showing: Frequency of refractive errors.

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Table 4 shows the frequency of myopic and hypermetropic eyes. The percentage of myopia(all categories ) is 84.3% while that of hypermetropia( all categories) is 15.69%. Thus myopia was the most commonly observed refractive error in our study.

Based on the study conducted, the variation of refractive error based on age, geographical location (different zones of Ahmedabad district), and family history was found statistically significant, highlighting the necessity for larger studies. However, variation among genders was found statistically insignificant.

DISCUSSION

Refractive errors are a major concern in school-going children. It is one of the major problems in school-going children, not only in India but across the world as well. Refractive errors are primarily of three types: myopia, hypermetropia and astigmatism. In our study of refractive errors in school-going children in the age group of 5–14 years seen at a tertiary care centre of western India, the percentage of refractive errors seen was myopia (28.61%), hyperopia (3.3%) and astigmatism (65.92%) as shown in Table 5. Refractive error affects a child’s capacity to learn and function academically, which may influence their general development and quality of life. This makes early diagnosis of the condition in children crucial. Young children with early onset vision impairment can experience delayed motor, language, emotional, social and cognitive development, with lifelong consequences. When children with visual impairment grow into adults, they may face lower rates of employment and higher rates of despair and anxiety. When these adults grow into old age, they are more susceptible to social isolation, difficulty walking, a higher risk of falls and fractures and a greater likelihood of early entry into nursing or care homes. One of the most prevalent causes of visual impairment among children in the world, uncorrected refractive errors have grown to be a major public health problem for healthcare officials.

One cannot ignore the rising trend in online education and its impact on the increasing incidence of refractive errors among children. Accurate and region-specific data on the frequency of visual impairment in children remains lacking despite a number of school-based screening programs. With the ever-rising number of students preferring dummy schools and online coaching centres as their only source of education, the implementation of school-based screening programs will only get tougher for the health authorities.

As shown in Table 5, a comparison of the prevalence of refractive errors in the present study conducted in Ahmedabad (n = 395) with studies from Kashmir (district Baramulla, n = 680) and Nepal (n = 118) revealed notable differences in the distribution of myopia, hypermetropia and astigmatism. In our study, myopia was observed in 28.61% of the cases, whereas the prevalence was significantly higher in Kashmir (57.4%) and slightly higher in Nepal (31.35%). The prevalence of hypermetropia was relatively low in Ahmedabad (3.3%), while it was markedly higher in Kashmir (36.1%) and Nepal (13.56%). The prevalence of astigmatism, which was 65.92% in Ahmedabad, was significantly higher than in Kashmir (5.3%), but comparable to Nepal (55.09%). These variations in refractive error distribution across different geographical regions may be influenced by genetic, environmental, and lifestyle factors, highlighting the need for region-specific approaches to vision screening and eye care interventions.

CONCLUSION

Our study provides baseline data about refractive error among school-going children in Ahmedabad. Our study shows that regular screening of refractive error is recommended among school-going children, especially in children with a positive family history of refractive error. Therefore, integrating eye health education into school health programs can increase awareness among teachers and parents, resulting in earlier detection of symptoms and timely referral for eye examinations and more compliance with spectacle wear. Furthermore, the importance of early detection and treatment cannot be overstated. Addressing refractive defects early not only restores vision but also promotes the child’s psychosocial and educational development, resulting in better societal outcomes. There are no measures to prevent the development of refractive errors, as it is inevitable, but the least we can do is mitigate their impact by slowing down the progression and preventing the complications before they arise.