|Year : 2018 | Volume
| Issue : 1 | Page : 32-37
Demographic profile of newly detected refractive errors among schoolgoing children in Thrissur district of Kerala
Sanitha Sathyan, Melanie Unnikrishnan, Anciya Kunjachan, KP Praseetha, Neethu Santy, Dona Wilson, Annie John, Merin Paul, Josni Jose
Department of Ophthalmology, Little Flower Hospital and Research Centre, Angamaly Ernakulam, Kerala, India
|Date of Web Publication||7-Jun-2018|
Nellikunnath House, Pudukad, Thrissur - 680 301, Kerala
Source of Support: None, Conflict of Interest: None
Aim: This study aims to analyze the demographic profile of newly detected refractive errors among schoolgoing children in Thrissur district of Kerala.
Materials and Methods: In this population-based cross-sectional study, 91,628 schoolgoing children between 6 and 17 years of age, from Thrissur district of Kerala were evaluated through school screening programs conducted at the respective schools. Demographic and clinical profiles of refractive errors among children with newly prescribed spectacles were analyzed.
Statistical Analysis: Demographic data were represented as bar charts and pie diagrams. Subgroup analysis for type for the influence of age, sex, and rural–urban location on the pattern of refractive error was analyzed using odds ratio.
Results: Out of the total 91,628 schoolgoing children, 1079 (1.18%) were newly prescribed with spectacles. Out of these, 549 (50.80%) were boys and 530 (49.20%) were girls. Myopic astigmatism was the most common refractive error (68.30%) in all the age groups taken together and individually. Simple myopia was seen in 13.81%, hypermetropic astigmatism in 13.07%, mixed astigmatism in 3.89%, and simple hypermetropia in 1.20% newly prescribed cases. In the 10–12 year age group, there was a significantly higher chance of occurrence of refractive errors of all types among the rural children in comparison to their urban counterparts. In the 6–9 years' age group, there was a significantly higher chance of occurrence of hypermetropia, hypermetropic astigmatism, and mixed astigmatism among the rural children when compared to the urban children.
Conclusion: Prevalence of spectacle use was less than the need for spectacle correction among schoolgoing children in Thrissur district of Kerala. As the prevalence of uncorrected/undercorrected refractive errors was more among the rural upper primary and lower primary school children, targeted strategies to address this deficit in service delivery need to be formulated.
Keywords: Kerala, newly prescribed spectacles, school screening program, service delivery, Thrissur
|How to cite this article:|
Sathyan S, Unnikrishnan M, Kunjachan A, Praseetha K P, Santy N, Wilson D, John A, Paul M, Jose J. Demographic profile of newly detected refractive errors among schoolgoing children in Thrissur district of Kerala. Kerala J Ophthalmol 2018;30:32-7
|How to cite this URL:|
Sathyan S, Unnikrishnan M, Kunjachan A, Praseetha K P, Santy N, Wilson D, John A, Paul M, Jose J. Demographic profile of newly detected refractive errors among schoolgoing children in Thrissur district of Kerala. Kerala J Ophthalmol [serial online] 2018 [cited 2021 Jul 25];30:32-7. Available from: http://www.kjophthal.com/text.asp?2018/30/1/32/233775
| Introduction|| |
Childhood visual impairment due to uncorrected refractive errors is a significant problem among schoolgoing children. In children, visual impairment due to uncorrected refractive errors can have an adverse effect on education, personality development, career opportunities, etc., in addition to the enormous socioeconomic burden on the society. Early correction of refractive errors results in reduction of number of children with visual impairment and amblyopia.
Many children with uncorrected refractive errors may be asymptomatic, hence active screening aids in early detection and timely intervention. Although school screening programs are conducted in every nook and corner of the country, accurate data on the current prevalence of childhood visual impairment is still lacking. There is no reliable data available regarding childhood visual impairment in the State of Kerala. One published study derived their sample of 40 schoolgoing children from hospital outpatient department, and the other derived their sample of 67 from a single semi-urban school population. Both these studies lacked adequate and representative samples, which made interpretations difficult.
Kerala, with its high literacy, human development indices and high school enrolment rates differs considerably from other States of India in sociocultural and economic standards. Hence, data from studies conducted elsewhere in India cannot be extrapolated to Kerala. Reliable data on the prevalence and distribution of refractive errors from population-based surveys are needed to plan cost-effective programs for reduction of visual impairment in our State.
Despite the apparently popular school screening programs throughout the State, that a sizeable part of our schoolgoing population with a high risk for development of amblyopia remains undetected, was observed in our outreach programs. The proportion of children with newly detected refractive errors was high even in urban/semi-urban areas. This prompted us to explore the demographic profile and clinical determinants of schoolchildren with newly detected refractive errors. This would be helpful in health policy formulation and advocacy toward the elimination of avoidable visual impairment among schoolgoing children of Kerala.
This study aims to evaluate the demographic profile and clinical determinants of schoolgoing children, between 6 and 17 years of age, who were newly prescribed with spectacles, through school screening programs conducted in Thrissur district of Kerala.
| Materials and Methods|| |
In this population-based screening, 91,628 schoolgoing children, between 6 and 17 years of age, from Thrissur district of Kerala were evaluated by a trained ophthalmic team, through school screening camps conducted at the respective schools.
The study adhered to the tenets of Declaration of Helsinki and was approved by the Institutional Review Board of the hospital. Sanction orders were obtained from the District Educational officer of Thrissur district and from the heads of the schools concerned, before the screening. Informed written consent was obtained from the parents/guardians of the children screened. Schools were selected according to multilevel cluster sampling.
The field staff included eight optometrists, an ophthalmologist, and a camp coordinator. Before initiation of the study, the field staff was familiarized with the testing protocols. All the students were screened using logMAR-based internally illuminated pocket vision screener (Medical Research Foundation, Chennai) at 3-m distance. Visual acuity cutoff used was 0.2 logMAR. Those who could read ≥0.2 logMAR were designated as “pass” and those who could not read were designated as “fail.” +1.50 D spherical lens test was done on all children who could read 0.2 logMAR to screen for hypermetropia. Those who could read with +1.50 D spherical lens were designated as “fail.” Criteria for referral to the base hospital were as follows:
- Children who could not read 0.2 logMAR (aided or unaided) or could read 0.2 logMAR with +1.50 D spherical lens
- Children designated to “pass” category with other ocular complaints such as asthenopia, watering, eyestrain, and headache
- Other ocular disorders suspected following orthoptic assessment and flashlight examination.
Hirschberg's corneal reflex test was done to determine the presence of strabismus. A cover-uncover test was then performed to in suspected cases. Anterior segment examination was done using a flashlight. Dry subjective retinoscopy and autorefractometry were performed in those suspected of refractive errors. Cycloplegic refraction was done in required cases using cyclopentolate (Cyclomid eyedrops 1%, JAWA pharmaceuticals)-Tropicamide-plus (Tropicacyl 0.8%-Phenylephrine 5%, Sunways pharmaceuticals)-Cyclopentolate, one drop applied 10 min apart. Homatropine hydrobromide (Homide eye drops 2% Indoco pharmaceuticals) eye drops one drop each applied 10 min apart was used for patients with a history of seizures or known allergy to Tropicacyl plus or cyclopentolate eye drops. Most of the children diagnosed with refractive errors were prescribed spectacles at the campsite itself and spectacles were dispatched to the respective schools within 2 weeks. Those requiring detailed evaluation or postmydriatic test were referred to the base hospital. All the interventions were provided free of cost and the children themselves chose the design and color of the spectacle frames from the inventory provided at the camp site. Final analysis was done for newly spectacle prescribed children, which included those with uncorrected refractive errors, those using suboptimal spectacles, those with poor compliance, and those with damaged spectacles which were not replaced.
All data were entered into Microsoft Excel spreadsheet and analyzed using SPSS software for Windows version 20.0 (SPSS Inc, Chicago, Illinois, USA). Descriptive analysis was done and represented as bar diagrams. Odds ratio (OR) was calculated for analyzing the influence of age, sex, and rural–urban location on the pattern of refractive error among children with newly prescribed spectacles.
| Results|| |
A total of 102,485 children between 6 and 17 years of age were scheduled for screening, out of which 91,628 (89.4%) children were available for screening. A total of 10,857 (10.5%) children who were absent on the day of screening were scheduled for screening for a later date and were not included in the data analysis [Figure 1].
Out of the 91,628 children, 1079 (1.18%) were prescribed with new spectacles. This includes those with newly diagnosed refractive error, those who did not own optimal spectacles or were using suboptimal refractive correction.
Out of these 1079 newly prescribed cases, 549 (50.8%) were boys and 530 (49.2) were girls. The mean age of the male group was 11.49 ± 3.15 years and that of the female group was 11.63 ± 2.94 years. The population was divided into four groups according to their age as follows: 6–9 years (n = 292, 27.06%), 10–12 years (n = 369, 34.20%), 13–15 years (n = 288, 26.69%), and 16–17 years (n = 130, 12.05%) [Table 1], [Figure 2].
|Figure 2: Age-wise distribution of various types of refractive errors in the study population|
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Of the total of 1079 children with newly prescribed spectacles, myopic astigmatism was present in 737 children (68.30%), simple myopia in 149 (13.81%), hypermetropic astigmatism in 141 (13.07%), mixed astigmatism in 42 (3.88%), and simple hypermetropia in 13 (1.20%) children [Figure 3].
|Figure 3: Distribution of refractive errors among newly spectacle prescribed group|
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Among the newly spectacle prescribed population, the prevalence of myopia in males was 12.02% and 15.6% in females. The prevalence of hypermetropia was 1.4% in males and 0.9% in females. Prevalence of myopic astigmatism was 32.5% in males and 31.9% in females. Prevalence of hypermetropic astigmatism among males was 14.5% and 11.5% in females. Prevalence of mixed astigmatism in males was 4.5% and 3.2% among females [Table 2].
|Table 2: Age- and gender-wise distribution of various types of refractive errors|
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OR was analyzed for the distribution of refractive errors with respect to age and the rural/urban location of the schools [Table 3].
| Discussion|| |
Childhood blindness is a priority area because of the number of years of visual impairment that follows. It is observed that spectacle compliance and timely replacement of damaged spectacles are important factors in deciding the success of school screening programs. Kerala tops the list of States with the highest health-related indices in the country , and the school eye screening programs have received priority in Government level as well as nongovernmental level eye health-related activities. However, sustainability of any public health model depends on its commitment to attend to the defaulters through proper follow-up strategies. Hence, ample attention is to be paid to the newly spectacle prescribed children in areas with relatively better service delivery records.
Variable prevalence of refractive errors has been reported in other parts of India: rural Andhra Pradesh, urban Delhi, rural  and semi urban Pune, rural Vellore, and Ahmedabad. Our study was not aimed at reporting the overall prevalence of refractive errors in the district of Thrissur. However the fact that newly prescribed spectacles accounted for 1.18% of the total of 91,628 screened, points towards possible high prevalence of refractive errors and underlying deficits in service delivery in the catchment area.
Out of these, 1079 children (7.07% of the total of 15,272 with refractive errors) were newly prescribed with spectacles. This group accounts for those schoolgoing children who had been missed out, suboptimally corrected, had poor compliance to spectacles or did not receive replacement of damaged spectacles, due to a variety of socioeconomic reasons. To the best of our knowledge, there are no previous studies catering to this specific aspect from the State of Kerala or from other parts of India.
Most of the newly prescribed spectacle users in our study belonged to the 10–12 years' age group, followed by 13–15 years, 6–9 years, and 15–17 years age groups. One of the reasons for this could be the higher incidence of refractive errors in the pubertal age, as described in literature. By the time, the children reach 15–17 years, asthenopic symptoms are more readily diagnosed, owing to the stress on academic activities consequent near work during this period. This may have resulted in more health-seeking behavior among children in the 16–17 years age group, leading to better spectacle use in such children. The prevalence of refractive errors in schoolgoing children generally increase with increasing age.,, However, higher demands of near work, coupled with better health-seeking behavior among the children in this age group may have resulted in the lower prevalence of unattended refractive errors, observed in our study.
In our study, there was no significant difference in the newly prescribed spectacles between males and females. Ande et al. in Andhra Pradesh had observed that there was no sex predilection for refractive errors in their study population. However, some studies have shown increased prevalence of refractive errors in females students, which was attributed to the relatively earlier attainment of puberty by girls in comparison to boys.,
In our study, the most common refractive error among new was astigmatism (85.26%), followed by simple myopia (13.81%). Hypermetropia was the least common refractive error (1.20%).
Myopic astigmatism was the most common refractive error (68.30%) in all the age groups taken together and individually (737 out of 1079 newly prescribed cases). Myopic astigmatism was highest in the 10–12 years (35.28%), followed by 13–15 years (26.19%), 6–9 years (25.92%), and 16–17 years (12.48%). Simple myopia was seen in 13.81%, hypermetropic astigmatism in 13.07%, mixed astigmatism in 3.89%, and simple hypermetropia in 1.20% of the newly spectacle prescribed cases. Although our study was on schoolchildren with newly prescribed spectacles, this pattern of distribution of refractive errors is comparable with the studies on the prevalence of refractive errors, conducted in different parts of the country.,,,,,
There was a significant odds of having refractive errors of all types (myopia: OR = 2.54, hypermetropia OR = 4.36, myopic astigmatism OR = 2.51, hypermetropic astigmatism OR = 2.90, mixed astigmatism OR = 5.30) among the rural children between 10 and 12 years in comparison to their urban counterparts. In the 6–9 years' age group, there was significant odds of having hypermetropia (OR = 2.25), hypermetropic astigmatism (OR = 1.14), and mixed astigmatism (OR = 1.12) among the rural children, when compared to the urban children. However, there was no higher odds of occurrence of refractive errors in the rural children in the 13–15 and 16–17 age groups than their urban counterparts. Dandona et al. and Murthy et al. have observed that while refractive errors are less common among rural than urban children, rural children have lesser access to refractive services., These were population-based cross-sectional studies conducted in rural Andhra Pradesh  and urban slums of Delhi. Our study was aimed at analyzing deficits in existing school screening systems, using the indicator of proportion of schoolgoing children prescribed with new spectacles. We observed that there was a higher odds of not having optimal spectacle correction among the rural children 6–12 years of age. In similar lines, Gogate et al. in Pune and Khandekar et al. in Madhya Pradesh have observed that spectacle compliance was poor among rural children. The proportion of children who would benefit from spectacles correction and yet do not own or wear glasses has been found to be high in studies conducted in China, Tanzania, and Mexico. This underlines the need for targeted strategies among the rural children in primary and upper primary schools.
Our study indicates that in spite of the school screening activities conducted regularly by governmental and non-governmental agencies in Thrissur district of Kerala, a significant proportion of the schoolchildren remain unattended to. This group of “newly prescribed spectacle” children is a heterogeneous group consisting of those newly diagnosed of refractive errors, those with poor compliance to spectacles, those using suboptimally corrected spectacles and those in whom damaged spectacles have not been replaced. In this study, this group of underserved children accounted to 7.07% (1079) of the total 15,272 with refractive errors. This is a major public health concern and the factors behind the occurrence need to be analyzed.
This is a pioneer study on the determinants of spectacle use among newly spectacle prescribed schoolchildren in Kerala. The merits of our study include a large and representative sample, use of the standard protocol for evaluation, and analysis of rural/urban determinants of spectacle availability among new spectacle users in the State of Kerala.
A major limitation of our study was that proportion of children with poor compliance, damaged spectacles, suboptimal spectacles, and newly diagnosed cases could not be individually ascertained as the data were pooled and entered in the onsite screening software as “newly prescribed spectacles.” Hence, we are unable to suggest specific strategies for each group. Another significant drawback was that those absent at the time of screening accounted for 10,857 (10.5%) of the total 102,485 children scheduled for screening initially. Although we had devised follow-up strategies for the absentees, their data were not included in the present study. We could have also missed out school dropouts and nonschoolgoing homeschoolers.
However, our study provides the baseline data indicating a significant shortcoming of the existing school health screening in Thrissur district of Kerala. This is invaluable in planning and policymaking so as to ensure sustainability of the current school screening models in our State.
| Conclusion|| |
Out of the 91,628 school going children of 6–17 years in Thrissur district of Kerala, the percentage of those newly prescribed with spectacles is 1.18%. Most of the newly prescribed spectacle users in our study belonged to the 10–12 years' age group, followed by 13–15 years, 6–9 years, and 15–17 years' age groups. Myopic astigmatism was the most common refractive error (68.30%) in all the age groups taken together and individually. Simple myopia was seen in 13.81%, hypermetropic astigmatism in 13.07%, mixed astigmatism in 3.89%, and simple hypermetropia in 1.20% newly prescribed cases. There was a significantly higher odds of having refractive errors of all types among the rural children between 10 and 12 years in comparison to their urban counterparts. In the 6–9 year age group, there was a significant odds of having hypermetropia, hypermetropic astigmatism, and mixed astigmatism among the rural children when compared to the urban children.
This study reports that the prevalence of spectacle use was less than the need for spectacle correction even in a relatively developed State like Kerala. Since the prevalence of uncorrected/undercorrected refractive errors was more among the rural upper primary and lower primary schoolchildren, targeted strategies to address this deficit in service delivery need to be formulated.
The authors would like to thank Ms. Mary Sebastian and Mr. Justin Jose for coordination of the screening program at schools.
Financial support and sponsorship
This study was financially supported by REACH project of Orbis International.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]