Jebmh.com Original Research Article

A Study on the Prevalence and Pattern of Refractive Errors among School Children of Medavakkam,

Jeevitha Jayapalan1, Jothi Gopu2, Sharmila Arcot Gunasekaran3, Hemima Josphina Herald4

1Assistant Ophthalmic Surgeon, Department of Ophthalmology, Mugavari Eye Hospital, Medavakkam, Chennai. 2Faculty, Department of Optometry, Mugavari Eye Hospital, Medavakkam, Chennai. 3Optometry Student, Department of Ophthalmology, Mugavari Eye Hospital, Medavakkam, Chennai. 4Optometry Student, Department of Ophthalmology, Mugavari Eye Hospital, Medavakkam, Chennai.

ABSTRACT

BACKGROUND Refractive error is defined as the state of refraction wherein the parallel rays of Corresponding Author: light coming from infinity are focused either in front or behind the retina with the Jothi Gopu, #15/6, Girigori Street, accommodation at rest. Refractive errors are one potential cause of visual , Chennai-75, impairment. So, it is important for our children to have visual examination at the . right time. School eye health services, an integral part of National Program for E-mail: [email protected] Control of Blindness, serves as an important tool for screening children at school DOI: 10.18410/jebmh/2019/590 level. Screening is done by subjective and objective refraction. National program for control of blindness was initiated by Ministry of Health and Family Welfare in Financial or Other Competing Interests: None. collaboration with district health authorities through public and NGO institutions.

The objective of the study was to estimate the prevalence and pattern of refractive How to Cite This Article: errors among the school going children in Medavakkam, Chennai, Tamilnadu. Jayapalan J, Gopu J, Gunasekaran SA, et al. A study on the prevalence and pattern METHODS of refractive errors among school This cross sectional study was conducted in the government schools of children of Medavakkam, Chennai. J. Evid. Based Med. Healthc. 2019; 6(44), Medavakkam during the period of June to November 2018. Total of 3727 students 2839-2842. DOI: of age group 8-17 years were enrolled for screening in this study. Students were 10.18410/jebmh/2019/590 examined for defective vision with Snellen’s chart and pin hole in ambient room illumination. Children with defective vision underwent a comprehensive eye Submission 14-07-2019, examination at Mugavari Eye Hospital and Research Institute, Medavakkam, Peer Review 19-07-2019, Acceptance 30-09-2019, Chennai. Published 01-11-2019.

RESULTS Of the 3727 children on roll, 188 had refractive errors. Prevalence of refractive errors was found to be 5.04%. The proportion of myopia, hypermetropia and astigmatism were 74.48%, 17.02% and 8.5% respectively. Myopia was noted to be the most common refractive error followed by hypermetropia and astigmatism.

CONCLUSIONS This study has provided the prevalence pattern of refractive errors of the study population. It concludes that Myopia is of high prevalence among the school going children. It also showed that children are at risk of developing refractive error and many of them were unaware of the same. Causes of prevalence and barriers to refractive error correction services are to be addressed earlier. Hence, an effective vision screening programme is needed to prevent visual impairment and blindness. In addition, children should be taught about principles of good posture, proper lighting to avoid glare, proper distance and angle between books and eyes.

KEYWORDS

Refractive Error, Prevalence, Visual Impairment, Myopia, School Children, School

Health Services, Eye Screening

J. Evid. Based Med. Healthc., pISSN- 2349-2562, eISSN- 2349-2570/ Vol. 6/Issue 44/Nov. 04, 2019 Page 2839

Jebmh.com Original Research Article

BACKGROUND approach in the treatment of refractive errors is to be

followed. Vision or visual perception is a complex integration of light The increasing demand of the enormous need for the sense, form sense, contrast sense and colour sense. Visual correction of refractive error worldwide, has been acuity is a measure of form sense, so it refers to the spatial considered as one of the priorities of global initiative for the limit of visual discrimination. Emmetropia is an optically prevention and elimination of treatable blindness: Vision 11 normal eye. Ametropia is a condition of refractive error. 2020 - The Right to Sight. Vision 2020 will be implemented Ametropia includes Myopia, Hypermetropia and through the following activities; a) Specific disease control Astigmatism. Prevalence of ametropia among the general measures, b) Human resource development, c) 12 population was given by Stenstroms study. Refractive error Development of appropriate technology and infrastructure. is considered to be the second leading cause of correctable blindness1 and one among the causes of visual impairment2 around the world. Visual impairment has a significant impact on children’s life. This in turn may lead to poor education, lower socioeconomic status, reduced employment opportunities and social stigmatization.3 Visual screening and diagnosis of refractive errors are especially important at certain times of life. The initial screening being in the first two decades, at the preschool and school years in a child who has failed vision screening. The second screening period being the mid-forties when presbyopia develops. The ideal place for initial visual screening would be the school setting, where the population, made up of children, can be targeted. Image 1 An ideal school eye health program should engage the department of health and education, be integrated in to the broad school health program and must be backed up by eye METHODS and child health services to manage referrals. The strategies to be used in the program includes education of the teachers This study was conducted in 6 government schools, and staff in primary eye care and vision screening, vision including the primary, middle and high schools in and around assessment with follow up system, engaging parent teacher Medavakkam, , Tamilnadu. Nearly 3727 meet up, involvement of other community based students were screened for refractive error, during the organisations and to understand factors associated with period of June 2018 to November 2018. Among them 51.7% spectacle wear. were boys and 48.3% were girls. A comprehensive eye Children may not be aware of their defective vision. examination was done for students with refractive error by They may adjust to poor vision by sitting in the first row or the team of Mugavari Eye Hospital and Research institute, sitting close to the black board, holding books close to their Medavakkam at their centre. The parameters studied were eyes, squeezing their eyes and even avoid their near work visual acuity by Snellen’s chart, anterior segment by slit lamp task to manage the visual discomfort.4 Myopia is of the biomicroscopy, cycloplegic refraction by retinoscopy and commonest cause of correctable refractive error.5,6 fundus examination by ophthalmoscopy. Therefore, it is very important to slow or even stop the progression of myopia in children.7 In 95% of visually Inclusion Criteria impaired children, the provision of spectacle improves their All school going children of age group 8-17 years were vision to within normal limits.8 An ideal spectacle should be included. non-allergic, resistant to corrosion, non-flammable, inexpensive, durable and adjustable. Also should be Exclusion Criteria available locally and of a style that is acceptable to the child. Children with other ocular abnormalities such as congenital These children also need follow up because refractive errors, ocular malformation, strabismus, corneal abnormalities and especially myopia, tend to increase during the first two retinal disorders were excluded from the study. The above decades. population were referred to Mugavari Eye hospital, Various environmental factors related to socioeconomic Medavakkam for further evaluation. status and lifestyle have been reported, and are widely considered to be possibly responsible for these changes.9,10

Refractive error in any population suggests that eye care services in general are inadequate. Strengthening and RESULTS

implementation of vision screening programs on large scale in those population will serve the need. A comprehensive Of the study population, 188 children had refractive error (5.04%) (Chart 1). 67.5% of them were boys and 32.5%

J. Evid. Based Med. Healthc., pISSN- 2349-2562, eISSN- 2349-2570/ Vol. 6/Issue 44/Nov. 04, 2019 Page 2840

Jebmh.com Original Research Article were girls (table 1). All the children were screened with Regarding the refractive error, changes occurs with Snellen’s chart. The pattern of refractive error were myopia ageing. A person is hyperopic in the early years of life and of 74.48%, hypermetropia of 17.02% and astigmatism of becomes myopic with the increase in age but again there is

8.5% (chart 2). The age wise prevalence of Myopia, a hyperopic shift after forty years of age Myopia tends to Hyperopia and Astigmatism are shown in Table 2. It was increase gradually until the mid to late teens. found that Myopia had a high prevalence among the total The relationship between near work and myopia has refractive errors, followed by Hyperopia and Astigmatism. been shown in different studies.13,14 In addition to the effect Our study showed the raise in the prevalence of refractive of near work, more children use electronic gadgets for their error as the children grows older as shown in Table 2. Our daily hobby time as a result of which, they are not engaged study also showed the prevalence of refractive error to be in outdoor activities. A recent clinical trial showed that the more in the male children 127 compared to female 61. incidence of myopia was about 10% lower in children who were engaged in outdoor activities. Few studies have shown the role of intense light in the prevention of myopia formation.15 The mechanism is that light stimulates the secretion of dopamine in the retina which in turn prevents ocular elongation during the process of ocular development and prevents myopia. In addition, the shared genes between the parents and children, environmental factors9,10 like urbanisation which has created a substantial change in children’s diet pattern that includes artificially grown foods, refrigerated and frozen ones, canned items and reduced hours of sleep are also related to the development of refractive errors.

Chart 1

Gender Refractive Errors Without Refractive Error

Male 127 (67.5%) 1800 Female 61 (32.5%) 1739 Total 188 3539 Table 1. Gender Distribution

Age Prevalence of Myopia Hyperopia Astigmatism Chart 2 (Years) Refractive Error 14 to 17 97 11 09 117 (62.24%) 8 to 13 49 15 07 71 (37.76) In India, school eye screening programs are largely Table 2. Age Distribution carried out by school-teachers trained under NPCB or by the

outreach teams of not-profit-eye hospitals. Most schools

however do not consider eye screening important enough to DISCUSSION formally include as part of their calendar activities. In that case obtaining permissions from the authorities for This study showed the prevalence of refractive error to be conducting the program is a major challenge, as they often 5.04% and the pattern to be myopia followed by hyperopia feel that it interferes with their regular activity. Also and astigmatism, among the school going children in absenteeism poses a major setback to cover the entire Medavakkam, Kanchipuram district. Similar prevalence of school in a single visit. refractive error (5.6%) was noted among the school children Also children with refractive errors who needs glasses in Villupuram and Puducherry (Muthukrishnanan et al). requires cycloplegic refraction and a post mydriatic test Similar pattern of refractive errors were found in the study before glass prescription. Effect of having a dilated pupil for related to Ahmedabad city (Sonam Sethi et al).This study some time can make children reluctant from getting the shows that the children among 14 -17 years of age are at examinations done. In certain schools, authorities have rules increased risk of developing refractive error and of myopia preventing instillation of any drops in the eye in school more commonly and many of them were not aware of their premises, forcing the team to refer children to vision care visual status. centres for refraction resulting in many drop outs. The number of people globally, with significant Spectacles use among children is a social stigma,3 refractive errors has been estimated to be one to two billion. especially in certain families. They are often seen as a Rates vary between regions of the world with about 25% of symbol of defective eyes. Creating awareness among the Europeans and 80% of Asians affected. Near sightedness is students, parents and community with a clear emphasis on 5,6 one of the most prevalent disorders of the eye. Rates the benefits of spectacle wear would serve the purpose. among children are between 1.2% to 42%. Teachers role should not only be restricted to vision

J. Evid. Based Med. Healthc., pISSN- 2349-2562, eISSN- 2349-2570/ Vol. 6/Issue 44/Nov. 04, 2019 Page 2841

Jebmh.com Original Research Article

screening but also should extend to monitor and ensure the REFERENCES

child gets appropriate management. Sufficient numbers of personnel and adequate infrastructure need to be put in [1] Dandona R, Dandona L. Refractive error blindness. Bull 12 place so that quality spectacles are made available to the World Health Organ 2001;79:237-243. needed ones. [2] Pascolini D, Mariotti SP. Global estimates of visual Follow up should be made an integral part to gauge impairment: 2010. Br J Ophthalmol 2012;96(5):614- compliance. Referral for other ocular conditions should be 618. made. Prescribing glasses for significant refractive errors. [3] Resnikoff S, Pascolini D, Mariotti SP, et al. Global Updation of screening protocols periodically to address all magnitude of visual impairment caused by uncorrected aspects of visual impairment. Providing choice of trendy and refractive errors, Bull World Health Organ colourful frames to children. Displaying famous personalities 2008;86(1):63-70. or cartoons wearing spectacles. Interventions to improve [4] Baltussen R, Naus J, Limburg H. Cost-effectiveness of compliance of the children. screening and correcting refractive errors in school Of the study population, children with refractive errors children in Africa, Asia, America and Europe. Health were subjected to stepwise ophthalmic examination and Policy 2009;89(2):201-215. were provided with best glasses, free of cost. Records of [5] Junghans B, Kiely PM, Crewther DP, et al. Referral rates those children has been filed for the future follow up. for a functional vision screening among a large Constant usage of spectacles of those children has also been cosmopolitan sample of Australian children. Ophthalmic ensured. Parents of those children were enlightened about Physiol Opt 2002;22(1):10-25. the importance of nutritious diet, adequate rest, involvement [6] Foster PJ, Jiang Y. Epidemiology of myopia. Eye (Lond) in outdoor activities and non-usage of mobile video games. 2014;28(2):202-208. [7] Rahi JS, Cumberland PM, Peckham CS. Myopia over the lifecourse: prevalence and early life influences in the

1958 British birth cohort. Ophthalmology CONCLUSIONS

2011;118(5):797-804. [8] Hashemi H, Iribarren R, Morgan IG, et al. Increased More near work due to increased educational demands has hyperopia with ageing based on cycloplegic refractions led to the raise in refractive errors among school children. in adults: the Tehran Eye Study. Br J Ophthalmol Greater use of mobile phones and video games serves as an 2010;94(1):20-23. added factor. Awareness programme regarding refractive [9] Park DJ, Congdon NG. Evidence for an ‘epidemic' of errors must be conducted for parents, teachers and others. myopia. Ann Acad Med Singapore 2004;33(1):21-26. Preventing visual impairment and maintaining eye health [10] Morgan I, Rose K. How genetic is school myopia? Prog since birth through adulthood comes under social priority. Retin Eye Res 2005;24(1):1-38. Every child must undergo vision screening regularly. Finally, [11] Global initiative for the elimination of avoidable the importance of outdoor activities and wearing spectacles blindness. Geneva, Switzerland: WHO, Program for the among those with refractive errors and effects of not using them should be explained to children. In addition, children Prevention of Blindness and Deafness 1997. should be taught about the importance of nutritious diet WHO/PBL/9761 including fresh fruits, greens and vegetables, whole grains [12] World Health Organization. Blindness and deafness unit and to avoid foods with high content of starches and low & international agency for the prevention of blindness. content of proteins. Screening eye care programmes (2000). Preventing blindness in children: report of a targeting school children need enormous knowledge WHO/IAPB scientific meeting, Hyderabad, India, 13-17 regarding perceptions and awareness of refractive errors April 1999. Geneva: World Health Organization among the adults, since the primary decision maker is often http://www.who.int/iris/handle/10665/66663 not aware of the problem to express his/her discomfort. [13] Rosenfield M, Gilmartin B. Myopia and near-work. Reed Training to address ocular problems relating to children Educational and Professional Publishing Ltd, 1998. should always be a part of residency program in [14] Saw SM, Tan SB, Fung D, et al. IQ and the association ophthalmology. with myopia in children. Invest ophthalmology Vis Sci 2004;45(9):2943-2948. [15] Rose KA, Morgan IG, Ip J, et al. Outdoor activity reduces the prevalence of myopia in children. Ophthalmology 2008;115(8):1279-1285.

J. Evid. Based Med. Healthc., pISSN- 2349-2562, eISSN- 2349-2570/ Vol. 6/Issue 44/Nov. 04, 2019 Page 2842