|Year : 2019 | Volume
| Issue : 2 | Page : 45-49
Prevalence of refractive errors in school-going female children of a rural area of Madhya Pradesh, India
Ankur Saxena1, Nitin Nema1, Ajit Deshpande2
1 Department of Ophthalmology, Sri Aurobindo Medical College and PG Institute, Indore, Madhya Pradesh, India
2 Department of Community Medicine, Sri Aurobindo Medical College and PG Institute, Indore, Madhya Pradesh, India
|Date of Submission||21-Dec-2017|
|Date of Acceptance||01-Oct-2018|
|Date of Web Publication||21-Aug-2019|
Department of Ophthalmology, Sri Aurobindo Medical College and PG Institute, Indore Ujjain State Highway, Indore, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
Background and Aim: Uncorrected refractive errors are the second most common cause of blindness after cataract. In previous studies from India, it is reported that majority of the children with blindness were female. Therefore, an obvious need was felt to screen school-going female children from a rural area for the prevalence of refractive error and associated ocular morbidity. Materials and Methods: A cross-sectional study was carried out in 1322 female students of rural schools. The permission required for screening of the children was obtained from the principal of the school. Students were examined by an ophthalmologist in their respective school premises. A brief history pertaining to eye problem and family history of ocular ailment were recorded. Clinical examination of the eye and refraction under cycloplegia, when needed, were done. Difficult and unmanageable cases were referred to the base hospital for further evaluation. Results: Refractive error was the most common ocular morbidity (38.7%). Myopia was the most common refractive error with a prevalence of 67.1%, followed by hypermetropia (18.8%) and astigmatism (14.1%). There was a decrease in the prevalence rate of visually impaired students to 0.4% (from the initial rate of 10%) after prescribing the spectacles. Other ocular morbidities encountered were strabismus (2.79%) and amblyopia (2.11%). Conclusion: Refractive error was the most prevalent ocular morbidity in the rural school-going girls, followed by strabismus and amblyopia. If properly treated and timely managed, a dramatic decline in the rate of refractive error-related visual disability can be achieved.
Keywords: Amblyopia, refractive errors, school-going children, strabismus
|How to cite this article:|
Saxena A, Nema N, Deshpande A. Prevalence of refractive errors in school-going female children of a rural area of Madhya Pradesh, India. J Clin Ophthalmol Res 2019;7:45-9
|How to cite this URL:|
Saxena A, Nema N, Deshpande A. Prevalence of refractive errors in school-going female children of a rural area of Madhya Pradesh, India. J Clin Ophthalmol Res [serial online] 2019 [cited 2020 Jul 3];7:45-9. Available from: http://www.jcor.in/text.asp?2019/7/2/45/264888
The global prevalence of blindness among children is approximately 0.1% and that in adults is 0.56%. In India, about one-third of the blind lose their eyesight at an early age. It is estimated that about 320,000 blind children live in India, which is more than any country in the world.
The World Health Organization (WHO) defines “low vision” as visual acuity of <6/18 but equal to or better than 3/60, or a corresponding visual field loss to <20°, in the better eye with the best possible correction. “Blindness” is visual acuity of <3/60, or a corresponding visual field loss to <10°, in the better eye with the best possible correction. “Visual impairment” includes both low vision and blindness.
Childhood blindness can be both congenital and acquired. Common causes of visual impairments in children in India are amblyopia, retinal disorders (including retinitis pigmentosa, coloboma, macular scar, and heredomacular degeneration), and corneal opacities and scars., These conditions should be diagnosed and treated timely to avoid permanent blindness.
Refractive error has not gained much attention among the causes of blindness. It is because blindness is mostly defined on the basis of best-corrected visual acuity (BCVA). However, if blindness was defined on the basis of presenting distant visual acuity, uncorrected refractive errors are the second most common cause of blindness after cataract.
In an Indian study, it is reported that the majority of children with blindness were female, and also, families are less likely to enroll a female child in the blind school as compared to the male. In a survey of different blind schools of the nine states of India, 60% students were found to be male. Looking at the prevailing scenario, an obvious need was felt to screen school-going female children of rural areas for the prevalence of refractive error and associated ocular morbidity. Therefore, this study was undertaken to find the prevalence of refractive errors in female students hailing from the rural area.
| Materials and Methods|| |
The present cross-sectional study was carried out in 1322 students of the rural area of Sanwer Tehsil, Indore district, Madhya Pradesh, India, from September 2014 to July 2016. The Institutional Ethical Committee permission was sought before commencing the study. The students were selected purposively by using a nonprobability sampling method. The list of schools meant only for female students in the rural area was taken from the administration. The permission required for screening the children was obtained from the principal of the school. A total of 1322 students from schools which gave the permission were enrolled in the study. The school authorities of each school were briefed about the objectives of the study. They were requested to inform the parents of the children about the benefits of the screening program and obtain their consent for the same.
The students were examined by an ophthalmologist in their respective school premises. The relevant information was collected from the class teachers and parents (whenever possible).
Demographic details and medical and family histories of each child were recorded. Ocular and visual complaints were noted. The ophthalmologist carried out a detailed eye examination of each student under the supervision of a schoolteacher. Distant visual acuity was measured using Snellen's chart. If the visual acuity was found to be <6/60, finger counting was done. When the child was unable to even count fingers, hand movements, perception of light, and projection of rays were tested. Hirschberg's corneal reflex test was done for the evaluation of squint. Color vision was tested using Ishihara chart.
General systemic examination of the child was done to look for systemic disease. External eye and anterior segment were examined using a torchlight. Pupillary dilatation was achieved using cyclopentolate eye drops. Two drops of 1% cyclopentolate hydrochloride at 5 min interval provide considerable cycloplegia sufficient for refraction in most children as described by Farhood. Refraction and fundus examination were performed 30 min after the instillation of the last drop in a dark room. A refractive error of −0.50 D or worse was labeled as myopia, +2.00 D or more as hypermetropia, and 0.70 D or more of cylindrical error as astigmatism.
Children who had systemic morbidity and/or ocular disease that could not be managed at the campsite were advised to attend the ophthalmic outpatient department of the base hospital with their parents for further evaluation and management.
| Results|| |
The age group of 1322 female students enrolled in the study was between 5 and 16 years. The socioeconomic status of these children ranged from lower-middle class to lower class.
There were 768 students with 6/6 distant vision in the better eye on presentation, which constituted 58.09% of the total examined girls. The number of students with visual acuity 6/18 or better in the better eye was 1190 (90%). About 10% (132 out of 1322) of students had visual acuity worse than 6/18 but better than or equal to 3/60 in the better eye. However, there was no student with visual acuity worse than 3/60 in the better eye [Table 1].
There were 1317 (99.6%) girls who had >6/18 vision in their better eye after the spectacle correction [Table 1]. The prevalence of students with visual impairment at presentation was 10% which got reduced to 0.4% after giving the refractive correction. No student had a vision of <6/36 in the better eye after prescribing the corrective glasses.
Refractive errors were seen in 511 students (out of 1322). The prevalence of refractive error in our study was 38.7%. Myopia was the most common refractive error which was present in 343 girls, hypermetropia was present in 96 girls, and astigmatism was present in 72 girls [Table 2]. The overall prevalence of myopia was maximum, 26%, followed by hypermetropia 7.3% and astigmatism 5.4%.
The prevalence of refractive error was the highest in the age group of 14–16 years with 54.4% (278 out of 511 students with refractive error) [Table 2]. The prevalence of myopia and astigmatism was observed to increase with age [Figure 1]. The prevalence of myopia showed a typical trend – it was 10% in the age group of 5–9 years (i.e., primary school children), 28.5% in 10–13 years age group (i.e., middle school children), and 61.5% in 14–16 years age group (i.e., high school children). The prevalence of hypermetropia was the highest in the age group of 5–7 years [Figure 2].
The prevalence of strabismus was found to be 2.79%; 37 students out of 1322 showed ocular deviations. Out of these 37 children, 34 had manifest squint and four had latent. Majority had exotropia (27 out of 37). The amount of deviation was measured using the Hirschberg corneal reflex test. Three students showed 45° or more of squint, 11 had 20°–35°, while most of the children (13 out of 37) had 10°–15° of ocular deviation.
The prevalence of amblyopia was 2.11%, 28 girls had visual acuity 6/12 or less in the worse eye. Seventeen of them were unilateral, whereas 11 were bilateral. Ametropia (n = 19) was the most common cause, followed by anisometropia (n = 4), strabismus (n = 3), and microcornea with corneal opacity (n = 2).
| Discussion|| |
Vision 2020 draft emphasized the importance of school screening programs in controlling childhood blindness, a simple vision assessment and distribution of spectacles to be integrated in School Health Program. The UNICEF considers a child as an individual below the age of 16 years. Assessment of the visual status of schoolchildren below 16 years of age for uncorrected refractive error and early detection of avoidable ocular morbidity could be the first step toward better ocular health, especially in rural area where low socioeconomic status, poor education, ignorance, and superstitions aggravate the problem.
A child's eye cannot be treated as a smaller version of an adult's eye, and it requires different management protocols and skills to treat it. It affects the child's development, education, mobility, and job opportunities., Therefore, in vision screening programs importance should not be given not only to the number of people screened but also on the number of individuals who experience substantial improvement in vision with optical correction.
In a study, in 9067 school-going children, it was found that 30.4% children had ocular morbidity with refractive error (29.3%) as the most common, followed by color blindness (1.2%), squint (0.8%), and Vitamin A deficiency (0.05%). Another study showed a prevalence rate of 31.6% ocular morbidity in 1561 schoolchildren examined, refractive error being the most common followed by squint. A similar finding was also reported in previous studies.,, We found refractive error to be the most common ocular morbidity in our study group with a prevalence rate of 38.7%, followed by squint (2.79%) and amblyopia (2.11%).
The presenting visual acuity of 6/18 or better, in the better eye, was seen in 90% of the girls, which improved after subjective correction in the current study. There were 99.6% children with BCVA of 6/18 or better in the better eye. About 10% girls had presented visual acuity worse than 6/18 but better than or equal to 3/60. However, only 0.4% students remained in this group, equivalent to visual impairment group according to the WHO, after giving the spectacle correction. Therefore, there was a substantial reduction in the number of students with visual impairment after the prescription of corrective glasses. The prevalence of visually impaired students was found to be 5.20% by Kalikivayi et al. Dandona et al. and Murthy et al. in their studies found 0.78% and 0.81% children to be visually impaired, respectively., Similarly, it was reported to be 2.50% by Uzma et al., 0.20% by Ghosh et al., and 0.40% by Jang and Park.,,
The prevalence of refractive errors in our study was 38.7% that comprised the most commonly seen ocular abnormality. An almost similar prevalence of refractive errors was reported in earlier studies.,, However, other authors found it to be less than our observation.,
Among the refractive errors, myopia had the highest prevalence of 67.1% (343 out of 511 students with refractive error). In an all-girl-based school survey by Basu et al., the prevalence of refractive error was 15.22%. The authors also found myopia to be the most common type of ametropia with a prevalence of 91.47%, followed by hypermetropia (4.60%) and astigmatism (0.04%). Similarly, other authors have also reported myopia as the most commonly encountered ocular morbidity in their studies.,
The prevalence of myopia and astigmatism was observed to increase with age in the present study. Dandona et al. stated that there occurs a gradual shift toward the less positive value of refractive errors with increasing age in both boys and girls. A similar observation was made by Sadana et al. who also noted the prevalence of myopia to increase from 1.3% in 5–7 years age group to 5.8% in 14–16 years age group. They further concluded that hypermetropia showed a reverse trend to myopia and it decreased from 2.2% in 5–7 years age group to 0.9% in 14–16 years age group. In our study, however, we could not draw any conclusion on the age-wise distribution of refractive errors as the participation of students from primary school was less.
A study done in Nigeria found 57.04% prevalence of latent squint and 0.89% of manifest. Gupta et al. reported the prevalence of strabismus to be 2.50%, whereas it was noted to be 0.30% in another study done in the Central India in 20,800 school-going children between 5 and 16 years of age., Kalikivayi et al. found 21 children to be having exodeviation and 9 esodeviation out of a total of 4029 school students examined. We noted a prevalence of 2.79% of strabismus. A total of 37 children (out of 1322) showed ocular deviation, 34 had manifest squint, and four had latent.
Amblyopia is a serious but treatable cause of visual disability in children. About 2.11% of school-going girls had amblyopia due to uncorrected refractive errors, anisometropia, ocular deviation, and corneal opacity. A similar finding was reported in other studies as well.,, In 2012, Anjaneyulu and Reddy reported a prevalence of 6.66% amblyopia in schoolchildren between 5 and 15 years of age from rural South India. They found refractive errors, anisometropia, and strabismus as the causes of amblyopia.
Refractive error is the most common ocular morbidity of concern in the current study. We found a large number of girls having treatable visual disability. On prescribing the corrective glasses, majority of them regained the vision fully. Myopia was the most prevalent refractive error among the school-going students. It is presumed to be due to the number of hours spent indoor doing near work.,
Refractive error is found to be the most common ocular morbidity in school-going girls in our study. The school teachers can help reduce the burden of childhood blindness by diagnosing the disability early, motivating the parents for comprehensive eye checkup of the child, and encouraging the child to wear the corrective glasses regularly. Eye screening program at the school level should be a routine for early detection of refractive errors to prevent and minimize long-term visual disability. It is one of the most cost-effective ways of eliminating visual handicap in schoolchildren of the rural area.
| Conclusion|| |
Refractive errors are the commonest cause of ocular morbidity in school-going girls. Myopia is found to be the most prevalent refractive error. Correcting the refractive error help improve the vision in majority of the schoolchildren.
Dr. BK Sharma, Biostatistician, Department of Community Medicine, Sri Aurobindo Medical College and PG Institute, Indore, Madhya Pradesh, India, deserves a special thanks for helping us in data analysis and preparation of the manuscript.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]