Prevalence of ocular morbidity in school children of India

Ocular morbidity refers to any clinically significant eye disease regardless of resultant visual loss and includes both blinding causes and non-blinding causes. Cataract, glaucoma, vitamin A deficiency, refractive error and trachoma are the major causes of childhood blindness in India. According to the National Program for Control of Blindness estimated National Prevalence of Childhood Blindness/Low Vision is 0.80 per thousand. About 30% of India’s blind population lose their sight before the age of 20 years and 80% of the blindness is avoidable. [1] 75 % of all children of school-going age are enrolled in school, [2] therefore they form an important control group where the certain age group of 6–15 years that represent 25% of the total population [3] is easily accessible and interventions such as screening, treatment and imparting health education can be promptly done. Furthermore, children are usually unaware of their problem and compensate by squeezing their eyes, sitting near blackboard and holding books close and their problems are usually noticed by caretakers. It is pertinent to identify the issues because ocular morbidities can affect education and overall development of a child and many of the conditions associated with blindness are also causes of child mortality; for example, vitamin A deficiency, measles, prematurity, congenital rubella syndrome, and meningitis. [4][5]

In one school eye survey done in rural population in a rural village of Hathras UP, India [6], a cross sectional study was carried out in 110 children of age group 3–12 years. Visual acuity measurement using Snellen’s E chart, retinoscopy and refraction under cycloplegia was done. Examination of the anterior segment, media, and fundii was also done. The prevalence of uncorrected visual acuity of 6/6 was 85.40%. Refractive error was the cause in 6.81% of eyes with vision impairment, out of which myopia and hypermetropia were present in 26.67% of eyes. Blepharo-conjunctivitis was present in 15.45% of children and Bitot’s spots were present in 0.90% of them. Colour blindness was found in one child. Researchers found that the prevalence of refractive error in rural school was 6.81 %. Blepharitis was the commonest cause of ocular morbidity. Since the survey was done on extremely backward region, even few 2nd standard students could not read the Snellen’s chart (local language optotype), which was the major limitation of this study. The study was successful in revealing the awareness of patients and their parents regarding their condition and exposing the status of ocular morbidities.

On another study done in rural area of North Maharashtra [7], a cross sectional study was conducted among 622 school going adolescents studying from 5th to 10th standard in the age group 10–16 years in field practice area of the department of Community Medicine of tertiary care teaching Hospital using a pretested structured questionnaire. The ocular examination of school children was done at the respective schools. All the data obtained was analyzed using the software StatistiXL version 1.8. Chi square test was used to observe the association of the ocular morbidities with respect to age, sex, education of father, occupation, class, and nutritional status. Prevalence of ocular morbidities was found to be 27.65 %. Refractive errors and Vitamin A deficiency were the most common ocular disorders. The prevalence of ocular morbidity showed significant association with socio-economic status (χ2=29.8, p<0.001), education and occupation of parents, while no significant association was found between ocular morbidity and sex of the school children (χ2=0.162, p=0.687), family type (χ2=2.41, p=0.121), and religion (χ2=6.77, p=0.08) of the school children. It was concluded that high prevalence of ocular morbidity among school children was observed in rural area of north Maharashtra in India. Refractive errors and Vitamin A deficiency were the most common ocular disorders. Prevention, early recognition and prompt treatment of ocular diseases by regular screening of students would definitely reduce ocular morbidity so that they can attain their full potential in the course of their education. Periodic screening of school children is very essential to improve the quality of eye-sight. [7]

Similarly, on a cross sectional study done among school-going children in the Union Territory of Chandigarh [8], The World Health Organization 30-cluster sampling technique was used to cover an optimum sample size of 9,067 students in 30 schools from 169 schools in Chandigarh with proportional allocation in different classes. Statistical analysis was done using SPSS version 15.0. Qualitative data was analyzed using the Chi squared test. Logistic regression analysis was performed to identify risk factors. Prevalence rates of refractive error, color blindness, squint, and vitamin A deficiency were found to be 29.3, 1.2, 0.8 and 0.05 %, respectively, with an overall prevalence of ocular morbidity of 30.4 %. The prevalence of ocular morbidity was Significantly higher among female students and among those studying in private schools. The prevalence rate increased significantly with age. A high prevalence of treatable or preventable ocular morbidity was observed among school-going children, and refractive error was the most common problem.

On another cross-sectional study done in Shimla, Himachal, North India, [9] Government and private coeducational schools were selected by stratified random sampling. About 1561 school children, studying in elementary through secondary class in these schools were examined from August 2001 to January 2002 in Shimla. A doctor did visual acuity and detailed ophthalmic examination. The Chi-square test was used to test differences in proportions. Differences were considered to be statistically significant at the 5% level. Prevalence of ocular morbidity was 31.6% (CI=29.9–32.1%), refractive errors 22% (CI=21.1–22.8%), squint 2.5% (CI=2.4–2.6%), color blindness 2.3% (CI=2.2–2.4%), vitamin A deficiency 1.8 % (CI=1.7–1.9%), conjunctivitis 0.8% (CI=0.79–0.81%). Overall prevalence of ocular morbidity in government and private schools did not show any statistical significant difference. Prevalence of conjunctivitis was significantly (P<0.5) more in government schools. Researchers concluded that a high prevalence of ocular morbidity among high-school children was observed. Refractive errors were the most common ocular disorders.

DISCUSSION

Consistent with reports from around the country refractive errors followed by blepharitis were the most common ocular morbidity, followed by conjunctivitis, Vitamin A deficiency. Squint and color blindness were also present. Prevalence was found to decrease with age. Similarly, females had a higher prevalence rate in most of the studies. Nutritional status of children was significantly associated with the occurrence of ocular morbidity. Rural areas have higher prevalence rate. The overall prevalence rate of ocular morbidity has been showing a decreasing trend in the recent years compared to one study done in 1999. [11]. Free spectacles program seemed to be effective at correcting refractive but compliance was poor among the students. Due to non-uniform definitions and inadequate survey methods, comparison of surveys was problematic. Strength of the above studies is its large sample size and the high coverage. However, the sample size collected from one region may not be representative of the whole country. Also there may be low patient compliance when asking them to visit the hospital and it is better for the doctor to go the villages and field treatment of minor diseases is preferred.

Varghese S., recently raised ethical concerns regarding a study done on Prevalence of ocular morbidity in school going children in West Uttar Pradesh [13], where the consent was taken from the school principals of respective schools for dilated fundus examination after tropicamide drop instillation. To be on par with the UNESCO guidelines [14], the author has suggested the use of standards that are feasible in India such as one published by Saxena et al [15] where an informed consent form was sent to the parents for the procedure.

Gaps in the study are related to underrepresented population sample from non-school-going children from the low socio-economic group who are also less likely to visit hospitals, the prevalence rate could potentially be higher in such groups due to factors such as eye care and personal hygiene. It is necessary to address the population samples from those areas too.

NEXT STEPS

There is a need to expand specialist pediatric ophthalmic services in India, and it has been recommended that there should be one well equipped child eye care center for every 10 million total populations. [12] The need to implement the eye checkup compulsorily in the school health program is found. A simple screening is an effective method for early detection of ocular problems and it can drastically reduce the disease progression. Vitamin A supplementation program is a short term intervention and can lose its effectiveness over time, so dietary modifications and ensuring availability of vitamin A rich food with additional measures like fortification should be pursued. Students should be taught about eye care and personal hygiene and schools briefed on how to identify children with ocular problems. Appropriate measures have to be taken to address the children of low socioeconomic status who are likely to be underrepresented in the above studies. A focus on screening and rehabilitation should be placed keeping in mind the decreasing trend of avoidable causes of blindness.

On the domain of the study method, attendance of the student on the day of the survey may affect the result of the study since students suffering from acute conditions such as conjunctivitis and corneal abrasion are less likely to attend the school and the prevalence rate of acute conditions may show a relatively low prevalence rate compared to other chronic causes such as refractive errors. A large sample size or systematic random sampling can be used to overcome it. Stratification of gender group is also necessary because in most of the studies done in India, there was a greater number of male students in a classroom. Age-and-sex adjusted prevalence can also be calculated by multiple linear regression with indicator variables for sex and age groups. Mantel-Haenszel procedures, stratified by age and sex can be used to test for trends and general associations in age- and sex-adjusted prevalences. Logistic regression analysis can also be performed to identify risk factors by fitting the model to assess the effect of age, gender and type of school.

References:

1. Danish Assistance to the National Programme for Control of Blindness, New Delhi, India (1996) Vision screening in school children Training module 1

2. Bhagyalakshmi J (2001) Presenting educational science: what next? Yojana 45:48–49

3. World Health Organization (1999) Report of WHO/IAPB scientific meeting, Hyderabad, India 13–17th April. Childhood Blindness Prevention. WHO/PBL/87

4. Gilbert C, Foster A. Childhood blindness in the context of vision 2020 — the right to sight. Bull World Health Organ. 2001; 79:227–32.

5. Solebo AL, Jugnoo R. Epidemiology, aetiology and management of visual impairment in children. Arch Dis Child. 2014; 99:375–9.

6. Gupta Y et al School eye survey Nepal J Ophthalmol 2011; 3 (5): 78–79

7. Deshpande Jayant D, Malathi K, National Journal of Community Medicine 2011;Vol 2 Issue 2 July-Sept 2011:249–254

8. Gupta, N., Arya, S.K., Walia, D. et al. Int Ophthalmol (2014) 34: 251.

9. Gupta M, Gupta BP, Chauhan A, Bhardwaj A. Ocular morbidity prevalence among school children in Shimla, Himachal, North India. Indian Journal of Ophthalmology. 2009;57(2):133–138.

10. Indian Journal of Basic and Applied Medical Research; June 2014: Vol.-3, Issue- 3, P. 358–362

11. Chaturvedi. S, Aggarwal OP., Asia Pac J Public Health 1999;11(1): 30–33

12. World Health Organization. Preventing blindness in children. Report of a WHO/IAPB scientific meeting. WHO/PBL/00.71. Geneva: WHO, 2000.

13. Singh V, Malik KP, Malik VK, Jain K. Prevalence of ocular morbidity in school going children in West Uttar Pradesh. Indian J Ophthalmol. 2017;65:500–8

14. UNESCO. Universal Declaration on Bioethics and Human Rights 19 October. 2005

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