PATTERN OF OCULAR MORBIDITIES AMONG PRESCHOOL CHILDREN OF BIRATNAGAR METROPOLIS OF NEPAL

of Biratnagar using total enumeraon sampling. Vision was assessed with Snellen's visual acuity charts and Kay Picture chart. Anterior and posterior segment examinaon was done using a hand-held portable slit lamp and a direct ophthalmoscope respecvely. Binocularity was assessed with a cover test at a distance and near targets and the Hirschberg corneal reﬂex. The refracve status of the eyes was assessed by performing stac renoscopy. All the data was analyzed according to sex, age, causes of visual impairment and types of ocular morbidity. Result The other types were congenital cataract vernal promptly


INTRODUCTION
Ocular health is a fundamental part of early child development and of overall health and well-being. Early childhood is a sensi ve period for the development of the visual system and any ocular disorders that occur during this period and if untreated can lead to visual impairment or 1 blindness. These visual impairments or blindness may affect an individual's health, employment op ons, educa onal 2 achievements and social func oning across the lifespan. Furthermore the visual impairment not only will affect the individual and their family but also for the community and country resul ng in a great loss of produc vity for the 3 country. The prevalence of childhood blindness is especially high in low-resource areas; among the blind children worldwide, 70-90% of them are in the poorest countries of Asia and Africa and the prevalence of blindness ranges from 0. 3 / 1000 children in affluent countries to 1. 5 / 1000 4 children in very poor communi es. The majority of 5 blindness is either poten ally curable or preventable . It is es mated that there are 1.5 million blind children in the 6 world, and that nearly 1 in 1,000 children are blind. Visual impairment has a significant impact on the affected child with regard to educa on, future employment, and social 7 welfare throughout life. Although eye examina ons in early infancy are important, they cannot predict the occurrence of condi ons that o en appear a er infancy, such as accommoda ve esotropia. Addi onal vision impairments may have emerged by then, and 3-year-olds are star ng to gain the communica ve abili es that allow them to be evaluated using methods similar to those used with adults. A par cular advantage of examining vision in the age group of 3 years is that it allows interven on at a me when the 8 problems are highly amenable to treatment. The goals of preschool vision screening are to iden fy children who have a vision impairment that may prevent them from obtaining maximum benefit from their educa onal opportuni es and may have an uniden fied serious vision problem (i.e., amblyopia). The lack of universal and age-appropriate preschool vision screening contributes to an unacceptable prevalence of permanent vision loss due to disorders like amblyopia, the majority of 9 which are preventable if detected and treated early. Ocular and/or visual defects are one of the most common reasons for the referral of young children to a hospital. Preschool vision screening, with treatment referrals as indicated, provides a unique opportunity to promote both vision health and the educa onal experience of the child. Significant refrac ve errors should be detected early in life. Condi ons like amblyopia, strabismus, and nystagmus are found to be prevalent in large numbers in the various records of the school screening done in different parts of our country. Preschool vision screening also reveals a significant number of children with impaired visual acuity due to refrac ve problems who do not have amblyopia. This group of children must be included in any analysis of the cost 10 effec veness of a preschool vision screening. Ocular problems create a nega ve impact on the child's learning and academic achievements in the future, leading to a decreased quality of life. Moreover, children cannot complain of symptoms related to their eyes and may not realize the fact that they cannot see well, so early detec on of ocular abnormali es will aid in an early interven on. We aimed to find ocular morbidi es among preschool children of Biratnagar metropolis in this study.

METHODOLOGY
This was a cross sec onal study conducted among 393 preschool children in the age group between 3 to 6 years at 5 different preschools of Biratnagar Metropolis from 21 Oct 2020 to 2021 Jan 30. We excluded children with some other comorbidi es and children who were mentally retarded. As per the data given by Biratnagar Metropolitan Council, there are 30 preschools in Biratnagar with approximately 2200 children. Out of this, 5 schools were selected by simple random sampling in the first phase and later on, children were again selected by total enumera on sampling method. The schools were inspected for the suitability of the screening process in terms of length of the screening room which had to be more than 4 metres, had adequate light (at least 300 lux in the room and test chart illumina on of about 500 lux) and was free from any distrac ons. A er these preliminary adjustments, the children were examined under the supervision of the teachers in their respec ve schools. An informed consent was taken from the teachers / guardians prior to the examina on. Demographics (gender, age, and ethnicity), family eye history, preterm history, medical history, and history of any ocular symptoms were all included in the ques onnaire. All preschool children in the study were examined for distant visual acuity test and depth percep on test using the Snellens distance visual acuity charts /kay pictures charts and Langsstereotest respec vely. These tests were performed by an optometrist and a trained staff nurse. Binocularity was assessed by cover test at a distance and near targets and the Hirschberg corneal reflex test. Distance sta c re noscopy at a working distance of 50 cm was used to determine refrac ve status. Anterior and posterior segment examina on was done by a hand held slit lamp and direct ophthalmoscope respec vely. Visual impairment(VI) was graded into mild, moderate and severe according to WHO criteria, i.e, visual acuity <6/18 was mild VI,visual acuity between 6/18 to 6/60 was moderate VI and visual acuity <6/60 was severe VI. Children whose visual acuity was less than 6/12 in one or both the eyes and those who failed in the depth percep on test were referred to the ophthalmology department at Birat Medical College Teaching Hospital for a detailed eye examina on.

STATISTICAL ANALYSIS
The results of the study were sta s cally analyzed using SPSS version 22, using chi-square test. Results on con nuous measurements are presented on mean ± SD (min-max) and results on categorical measurement are presented in numbers (%).A P-value of <0.05 was considered sta s cally significant.

RESULT
Among 393 preschool children, the majority (56.99%) were female. The mean age of children was 5 years (table 1).  Table 5 The prevalence of ocular morbidity in this study was found to be 20.1 % (79 children).The propor on of ocular morbidity is shown in table 2. Refrac ve error was the most common type of ocular morbidity which was seen in 14.7% of children (58). The overall prevalence of myopia, hyperopia, and as gma sm was 31(7.9%), 19(4.8%), and 8 (2.1%), respec vely (table 3). The distribu on of refrac ve error in both sex groups is men oned in Table 5.
The prevalence of refrac ve error in male is 23 (13.6%) as compared to female, 31(13.8%) which is not sta s cally significant (p=0.948). The other types of ocular morbidi es were strabismus in 1.3%, congenital cataract in 1%, conjunc vi s in 1 %, chalazion in 1.3%, Vkc in 1% and congenital ptosis in 0.6% Visual acuity was assessed both monoculary and binocularly. Majority of preschool children had normal vision (337).Out of the children having visual impairment, 8.7% had mild visual impairment and 5.6% had moderate visual impairment. The cause of visual impairment in all children was refrac ve error except for 2 children in whom the causes were congenital ptosis and strabismus respec vely.

DISCUSSION
The prevalence of ocular morbidity among preschool children in our study was found to be 20.1% which was similar to most of the studies around the world where 11 percentages varied from 12. 7% to 22. 8%. The prevalence of ocular diseases among preschool children in Malaysia was documented to be 14. 8% which was lower than our 12 study. However, one study found that ocular morbidity was 24. 6% among children in India which was higher than 13 our study. In the USA, a prevalence of ocular diseases and significant cusses among school children was found to be 28. 8% and previously undetected eye condi ons being 19. 14 8% ,that prevalence of ocular diseases markedly higher than in this study. This varia on may be because of different sample sizes and the effect of mandatory school eye screening programs in their part of the world compared to ours where there is no any cer fied government policies which includes these sort of screening programs. The most common ocular morbidity among preschool children was the refrac ve error (14.7 %), which was also the most common ocular morbidity among children of 15 different countries. Myopia was the most common (7.9%) type of refrac ve error among the children which was 15,16 consistent with some interna onal studies. In our study, the prevalence of myopia was 7.9%, which is more 17 18 prevalent than in studies done in India ,Great Britain and 19 the United States . The more recent studies showed that Hong Kong (36. 7%) and South India ( 32% ) had a higher prevalence rate of refrac ve errors among school children 20,21 of age 3year -18year as compared to this study. These differences may be explained by the different diagnos c criteria, the racial or ethnic varia ons, different age groups and different sample sizes in different studies.
However, the lower prevalence of refrac ve errors (2. 7 -5. 8%) has been reported among school children of age range 22 5 -15 years from Finland, Africa, Nepal and Chile. The prevalence of Vernal Kerato conjunc vi s in this study is 1% which is much less than studies done amongst primary school children in Ethiopia which showed that the 23 prevalence of vernal conjunc vi s was very high (31.3%). This difference may be because of fewer par cipants in our study group compared to them and also the fact that the number of females are more in this study and Vernal 24 conjunc vi s is a disease commonly affec ng the males. The prevalence of conjunc vi s in our study is 1%. The prevalence of conjunc vi s and other infec ous diseases 25 has been reported to be 0.33 -2.77 % in some parts of India. This varia on can be explained by the difference in geographical loca on, seasonal varia ons, different socioeconomic status and personal hygiene of children.
Children are a precious asset of the na on. Most of the ocular diseases observed in our study were either preventable or treatable but if neglected may lead to severe disabili es or blindness. As the burden of blindness is already high in our country, we have to go through a blindness preven on approach, beginning right from the early childhood and preschool and school eye-screening programmes should be an integral part of it.

CONCLUSSION
The rela vely high prevalence of refrac ve error and presence of other ocular morbidi es in our studied popula on suggests that there is a need for a large-scale community-based preschool screening program in Nepal so that affected children can be iden fied early and appropriate treatment can be started promptly. We will also recommend follow up study for this issue.

RECOMMENDATIONS
We recommend the screening of preschool children for early evalua on of ocular morbidi es.

LIMITATION OF STUDY
The study could have been be er if follow up was done further for assessment of long term visual outcome. Also, the mul central study would have been be er for this study.

ACKONWLEDGEMENT
We are very grateful to management team of preschool for gran ng permission to evaluate and perform research on preschool children.