OCULAR HEALTH STATUS OF PRIMARY SCHOOL
CHILDREN IN ABAGANA-NJIKOKA LOCAL
GOVERNMENT AREA OF ANAMBRA STATE, NIGERIA.
BY
OKOYE OBIEKWE (DR)
1
OCULAR HEALTH STATUS OF PRIMARY SCHOOL CHILDREN IN ABAGANA -NJIKOKA LOCAL GOVERNMENT AREA OF ANAMBRA STATE NIGERIA
A DISSERTATION SUBMITTED TO THE NATIONAL POSTGRADUATE
MEDICAL COLLEGE OF NIGERIA IN PART FULFILMENT OF THE
REQUIREMENTS FOR THE AWARD OF THE FINAL FELLOWSHIP OF THE
MEDICAL COLLEGE IN OPHTHALMOLOGY, FMCOph
BY
OKOYE OBIEKWE NOVEMBER 2007
2 Declaration
I hereby declare that this work is original unless otherwise acknowledged. It has not been presented to any other college for a fellowship nor has it been submitted elsewhere for publication in part or full.
3 Attestation
This is to certify that study reported in this dissertation and the writing thereof were done by Dr. Okoye Obiekwe under our supervision.
Name of Supervisor Professor R. E. Umeh Department of Ophthamology UNTH Enugu.
Signature Date
Name of Supervisor Professor U. F. Ezepue Department of Ophthamology UNTH Enugu.
Signature Date
4
DEDICATION
This work is dedicated to my darling wife Ngozi for her continual love and support; and our lovely children – Chiamaka and Chinemerem.
5 ACKNOWLEDGEMENT
I am greatly indebted to my supervisors – Prof. R. E. Umeh and Prof. U. F. Ezepue for the personal interest and commitment, which they gave to this work. Their criticisms and corrections were most helpful.
My profound appreciation also go to my teachers in the department of Ophthalmology, University of Nigeria Teaching Hospital Enugu namely Prof. E. N. Onwasigwe, Dr. N. O. Magulike, Dr. P. B. Nworah, Dr. C. M. Chuka-Okosa, Dr. B. I. Eze, Dr. F. C. Maduka-Okafor, Dr. A Aghaji, Dr. O. I. Okoye and Dr. L. Ubaka. They made the residency training worthwhile. I also thank Dr. C.N. Onwasigwe for her valuable assistance in the area of statistics. She was a great support despite her tight schedule.
My sincere gratitude also goes to the administrative secretaries, headmistresses, headmasters and entire staff and pupil of the Primary Schools in Abagana – Njikoka Local Government Area. Their co-operation is deeply appreciated.
I wish to thank all those who provided me with relevant literature – Prof. U. F. Ezepue, Prof. R. E. Umeh, and Dr. C. M. Chuka-Okosa.
6 I sincerely appreciate the various assistance recieved from my friends and colleagues: Dr. E. Achigbu, Dr. U. Agwu, Dr. N. Oguego and Dr. J. Azu-Okeke during the course of this study. I am grateful to Miss Ifesinachi and Mr Ikechukwu for their secretarial assistance.
I am particulary greatly indebted to my lovely wife, Ngozi Okoye. She was solidly behind me throughout the study and in fact during the entire residency period.
Finally my immeasurable thanks to the Almighty God whose unfailing love and mercy have been upon me and my family. His Fatherly eyes were continuously upon us throughout the duration of this study.
7
Table Of Contents
Title page i Declaration ii Attestation iii Dedication iv Acknowledgement v List of Figures and Tables ix Summary CHAPTER 1 1.1 introductions 1 1.2 study area 7 1.3 objectives 11 CHAPTER 2 Literature review 12 CHAPTER 3 Materials and method 22 CHAPTER 4 Results 29 CHAPTER 5 Discussion 38 CHAPTER 6 6.1 conclusions 49 6.2 Recommendation 49
8 REFERENCES 52
APPENDIX i. Modified WHO/PBL Eye Examination form 58 ii. Consent form 60 iii. Ethical clearance approval 62
9 LIST OF FIGURES AND TABLES
TABLES Table 1: Distribution of primary schools in Abagana - March 2006 Table 2: WHO Classification of Visual Impairment Table 3: Distribution of sample population by Visual Acuity in the better eye. Table 4: Causes of low vision amongst the study subjects Table 5: Distribution of ocular disorders amongst the study subject.
Table 6: Distribution of the ocular disorders seen in the study subjects by age (n=2092). Table 7: Classification of ocular disorders in the affected eyes of the study subject into preventable and treatable disorders.
Fig 1: Map of Njikoka local government area with inset map of Nigeria. Fig 2: Age and sex distribution of the study subjects. Fig 3: Anatomical site of ocular disorder in the affected eyes of the study subjects.
10 Summary
A cross sectional survey of the ocular status of primary school children in Abagana - a rural community in Njikoka Local Government
Area of Anambra state of Nigeria, was undertaken. The available children in all the 8 primary schools aged 6 to less than 16 years were interviewed and examined with snellens chart, pen torch, head loupe and direct ophthalmoscope. Findings were recorded using the modified World Health Organization/Programme for Prevention of
Blindness (WHO/PBL) eye examination form.
More males 1081 (57.7%) than females 1011 (48.3%) constituted the sample population giving a male/female ratio of 1.07 to 1, (p=
0.0013).
There were 20 different types of ocular disorders found in 127 out of 2092 children examined giving a prevalence of 6.1%. The most common ocular disorder was vernal conjunctivitis (48.1%) followed by refractive error (11.0%). The highest number of ocular disorder
61(48.0%) occurred in the age group 10 to 13 years.
The number of school children with a visual acuity <6/18 in the better eye was 6 (0.3%). Of these, 4 (0.2%) were due to
11 preventable ocular disorders while 2 (0.1%) were neither preventable nor curable. Of the 4 (0.2%) cases of monocular blindness, 3
(0.14%) were preventable.
The findings in this study indicate that most of the causes of visual impairment in the school children surveyed were avoidable and appropriate application of preventive and promotive primary eye care would go a long way in improving the ocular health status of primary school children in this locality.
12
CHAPTER 1
1.1 Introduction
Background and Justification
The prevalence of blindness in children (the proportion of the child population who are blind at a specific point in time) varies from approximately 0.3/1,000 children in wealthy regions of the world, to
1.2/1,000 in the poorer countries/regions.1
Blindness among children is more common in the poor region of the world for three main reasons2: first, there are diseases which can lead to blindness from causes which are not prevalent in industrialized countries, example, measles, vitamin A deficiency, and ophthalmia neonatorum. Second, there are fewer well equipped facilities and personnel trained in managing treatable causes of blindness. Third, is the contribution of ignorance, poverty and superstition in the rural areas.
Incidence data are very difficult to obtain, but it has been estimated that there are 8 new blind children for every 100,000 children each year in industrialized countries.2 In the developing countries, approximately
13 500,000 children become blind every year – one every minute and about half of them die within one or two years of becoming blind. 3
The high number of blind years resulting from blindness during childhood is one of the reasons why the control of childhood blindness is a priority of the World Health Organization/International Agency for
Prevention of Blindness (WHO/IAPB) Vision 2020: The Right to Sight
Programme.4
Children who are blind have to overcome a lifetime of emotional, social and economic difficulties, which affect the child, the family and the society.5 Loss of vision in children influences their education, employment and social life.5 Childhood blindness is second only to adult cataract as a cause of blind-person years. Approximately 70 million blind-person years are caused by childhood blindness worldwide.6
Vision plays an essential role in development and visual deficit constitutes a risk factor not only for visio-sensory development, but also for overall development.7 Timely screening for the early detection of eye and vision problems in children is vital to avoid lifelong visual impairment. Early detection provides the best opportunity for effective treatment.8
14 In all regions of the world there are causes, which are amenable to primary, secondary and tertiary prevention, but the proportions vary from region to region. In the vision 2020 programme, the following conditions are priorities for control 9:
Corneal scarring, due to measles, vitamin A deficiency, harmful
traditional eye medicines, and ophthalmia neonatorum, constitute
priorities in poor and very poor regions.
Cataract and glaucoma: Important treatable causes in all regions.
Retinopathy of prematurity - a condition important in middle-
income countries, and in urban centers in developing countries.
Refractive errors which is a treatable cause in all regions.
Low vision: Services need to be expanded and developed in all
regions.
Amongst others the following targets have been agreed for disease
control9:
Reduce the global prevalence of childhood blindness from
0.75/1000 children to 0.4/1000 children.
Elimination of corneal scarring caused by vitamin A deficiency,
measles, or ophthalmia neonatorum.
15 All school children to receive a simple vision screening
examination, with glasses provided for all those with significant
refractive error. This should be integrated into the school health
programme.
School-age children (6 –15 years) represent 20 – 30% of the total population of most third world countries10. For Nigeria this translates to an estimated 20 – 30 million children. In some states in southern
Nigeria, 80% of the children are in school and can best be reached there for any health care program11. Even assuming a case scenario of a school drop out rate of 50%, there will still be 10-15 million school age children 11. Therefore, school children form an important large target group, which must be screened adequately for early detection of eye diseases and prevention of blindness.12.
Most children and teachers have a fair knowledge of what a normal eye looks like13. They perceive healthy eyes to be those which could see well, and diseased eyes to be those, which have “redness”, watering, dirty discharge, pain, and itching; or those that have “weak eyesight” and blindness 13. Teachers note that children with eye problems “have difficulty seeing blackboard well”, “screw up their eyes”,
16 and “hold their books too close”13. However, many of them have serious misconceptions, for example use of harmful traditional eye medications, especially, in the rural communities 13.
Seventy percent of the ametropic groups are unaware of their visual defect, which can lead to the development of amblyopia14. This is of importance, because the longer treatment for amblyopia is delayed, the lower the chance of complete recovery. On average, the literacy development of the visually impaired children appeared to be hampered by their visual defects 15. Myopia and other ocular defects retard the progress of many albinos in school and they eventually drop out to seek disastrous menial outdoor occupations 16.
Ocular morbidity following eye trauma in children is common especially in rural communities due to delay in seeking specialist treatment and lack of sophistication of the treatment, especially in severe cases 17. The injuries were commonly sustained during domestic activities (29.8%), at play or sports (23.7%), in the schoolroom (16.7%) and during farm work (10.1%) 17.
Measles with its attendant corneal destruction accounts for most blindness in children18. Trachoma is seen as a community disease
17 needing a community approach to factors such as waste disposal, water supply and cyclic re-infection.18 Blindness is not a public health problem alone, but low educational, socioeconomic states, unscientific cultural practices, and poor environmental status play a major role.19
Not all ocular conditions result in visual impairment. The prevalence of non-vision-impairing conditions (NVIC) is 14.6%20. The main NVIC were allergic conjunctivitis (3.7%).20 Although NVIC are non- vision impairing, affected individuals may have need for frequent clinic visit with the attendant impact on their academic performance.
Sufferers of allergic conjunctivitis exhibit a significantly higher incidence of asthma, nasal symptoms, food allergies and other allergies. They tend to experience quality of life reduction in general health 21. More worrisome in the rural setting is the potential use of harmful traditional eye medication and improper use of proprietary medications such as steroids for vernal keratoconjuctivitis and the like, which may result in vision impairing complications. In the developing countries of which
Nigeria is one, health problems are found more in the rural than in the urban areas10.
18 This study specifically targets primary school children in a rural community of Anambra state of Nigeria. The aim is to determine the prevalence of ocular disorders and their common causes in order to propose a modality for applying the findings in the prevention of blindness programmes. School children are a selected group and provide a captive audience, which can be studied easily. They can also be targeted for specific intervention programme.
1.2 Study Area
Abagana is one of the 6 rural communities that make up the Njikoka local government area of Anambra state of Nigeria. Others are Abba,
Enugwu Agidi, Enugwu Ukwu, Nawfia and Nimo.
Anambra state lies in the southeast geo-political zone of Nigeria.
Abagana is bounded in the north by Ukpo, which is in Dunukofia local government area, in the west by Enugu ukwu and in the southeast by
Enugu-Agidi.
The villages in Abagana are Ozalla, Umundum, Epupe, Adegbe,
Oraofia, Ofenaochi, Uruokpalla, Amanya, Akpu totaling 9 in number.
Abagana houses the headquarter of Njikoka local government area
19 which is about 10km from Enugwu Agidi junction off Enugu – Onitsha express road. Only the road passing from Enugwu-Ukwu through
Abagana to Ukpo is tarred. Other roads interconnecting the villages are not tarred. The means of transportation in Abagana and Anambra state in general is by small commuter buses and predominantly motorbikes popularly known as “Okada” as well as bicycles. Electricity is available in all the villages. All the major mobile telephone networks in Nigeria cover the area.
The total population of Abagana is 44,880. The number of males is
22,348 and the females 22,532. This data is according to the 2005 national census. The people of Abagana are Igbos with farming and petty trading as the main occupation. Majorities are Christians but other religions do exist.
According to the statistics at the Njikoka Local Government Area
Education unit, Abagana has 8 primary schools with 2,336 pupils and
128 teaching staff (Table I)
20 Table I: DISTRIBUTION OF PRIMARY SCHOOLS IN ABAGANA -MARCH
2006
Schools Number of school children
Ozalla primary school Ozalla 282
Igwebuike primary school Umundum 302
Central school Ohafia 272
St James primary school Epupe 289
Hilltop primary school Adegbe 301
St John primary school Ofenechi 397
St Michael primary school Ofenechi 300
Epepe primary school Akpu 293
Total 2336
In Abagana, there is one community health center and a comprehensive health center of the University of Nigeria teaching hospital. There is only
1 nurse with ophthalmic training at the comprehensive health center. At the time of this study there is no ophthalmologist or optometrist in the entire community.
21
22 1.3 Objectives
General objectives
To determine the ocular health status of primary school children in
Abagana with a view to obtaining baseline data for an effective school eye health services.
Specific Objectives
1. To determine the prevalence of ocular disorders among primary
school children in Abagana, a rural community in Njikoka Local
Government Area of Anambra state.
2. To identify the causes of ocular disorders in the children studied.
3. To propose a modality for applying the findings for an effective
school eye health services.
23 CHAPTER 2
Literature Review
A global estimate of the magnitude and causes of visual impairment based on the 1990 world population data gave 38 million blind.22 This estimated was later extrapolated to the 1996 World population to give 45 million blind, and subsequently projected to the
2020 world population estimating 76 million blind.22 This increasing trend provided the basis for the 1999 launch of VISION 2020, the Global initiative for the elimination of avoidable blindness. New analysis using
2002 data reports that 37 million were blind. 22 However, refractive error was not included, which implies that the actual global magnitude is greater.22 Low vision (< 6/18 to light perception in the better eye) is estimated to affect approximately three times as many people as does blindness. 23
Paul et al24 in summarizing available data regarding pediatric blinding diseases worldwide found that 5% of worldwide blindness involves children younger than 15 years of age; in developing countries
50% of the population is in this age group24. By World Health
Organization criteria, there are 1.5 million children worldwide who are
24 blind: 1.0 million in Asia, 0.3 million in Africa, 0.1 million in Latin
America and 0.1 million in the rest of the world24. There are marked differences in the causes of pediatric blindness in different regions, apparently based on socioeconomic factors.
In the United States, the 3 leading causes of paediatric blindness are cortical visual impairment, retinopathy of prematurity, and optic nerve hypoplasia24. In developing countries, 30% to 72% of pediatric blindness is avoidable, 9% to 58% is preventable, and 14% to 31% is treatable 24.The leading cause is corneal opacification caused by a combination of measles, xerophthalmia, and the use of traditional eye medicine24.
In Nigeria, a cross sectional survey of three blind schools in
Northern Nigeria was done to assess the causes and distribution of childhood blindness25. Of the 199 students enrolled in the schools, 191
(91%) were examined aged 5 – 17 years. corneal scar was the single most important identifiable cause of childhood blindness (15 – 17%).
Umeh26 in a study of the treatable causes of blindness in a school for the blind in Nigeria examined 62 subjects ages ranging between 10
25 to 26 years (mean 18 years). Corneal scaring and staphylomas are the second commonest cause of visual loss (17.7%).
These figures are lower than the 22.0% in the study by Waddle in
Uganda27. Waddle studied children from birth to < 16 years – age range more vulnerable to the infective cause of corneal scarring, for example, measles and nutritional causes such as xerophthalmia.
However the study in Uganda27 comprises of both subjects in schools and in the communities as against that done in Nigeria with a selection bias as only blind schools 25, 26 were selected for the studies.
Globally, traumatic eye injuries is a recognized cause of blindness and visual impairment in children.28In high-income families, social dysfunction, depression and unemployment play a major role, for instance, in child battering (Physical assault of children) which may result in traumatic eye injuries.28In developing countries, poverty, social and cultural beliefs and taboos and exposure to traditional practices predispose the vulnerable pediatric group to abuse. Herbal ocular
“medicine” is responsible for an estimated 8-10% of corneal blindness in
Africa28.
26 In Bangui, central African republic29, a prospective study conducted on 194 cases seen in the eye unit over a 3 year period revealed punishments (25.9%) as the major cause of ocular injuries in children aged 0 – 15 years. Other causes are accidents during games
(19.3%) and fight (18.8%).
In Cote d’Ivoire,30 ocular traumas represented 4% of new admissions in ophthalmology, and 29% of these injuries occurred in children. Unlike the studies in Bangui29, accidents during play are the commonest cause of injury30. Open eyeball wounds were the most common injury and the primary posttraumatic sequelae were corneal scar30.
In Nigerian Teaching Hospitals, previous workers17, 31–36 documented injuries during domestic activities, at play or sports in school, during farm work and punishments as major causes of ocular injuries in children. Generally, corneal injuries accounted for the commonest type of injuries based on anatomical site resulting in posttraumatic corneal scars, staphylomas and phthisis bulbi.
As noted by Onwasigwe et al, 36 visual outcomes in patients in developing countries were worse than that of reports from developed
27 countries. In Benin35, Nigeria, 76.3% were blind at presentation (V.A
<3/60). This was mainly due to the severity of injury and late presentation in the eye clinic.17,35 As many as 68.6% presented after 24 hours in the Benin study while in Enugu study17, only 28.5% reported in the first 24 hours and as many as 10.5% after 1 month. Other contributing factors to the poor prognosis in developing areas are injudicious use of orthodox eye medications, use of harmful traditional eye ‘medications’ 35, and lack of sophistication of the treatment, especially in severe cases17. In most of the cases of eye injuries in children, the causative factors are highly preventable36.
Globally, refractive error is the most common cause of visual impairment in children37. There is evidence that the prevalence of refractive errors varies with ethnicity38. Compared to white Americans,
Asian Americans have a higher prevalence of myopia, while Africans have a lower prevalence38. Native Americans have a higher degree of astigmatism but not of myopia38. Myopia has also been associated with scholastic success, reading ability, educational level of parents, and higher family income38.
28 In Chile39 the prevalence of uncorrected refractive errors among children was 15.8%.In Malasia40, Goh et al found the prevalence of uncorrected visual acuity to be 17.1%. In Botswana41, a survey of children in schools and in the community showed that 1.5% of children aged 5 – 15 years had a visual acuity of less than 6/18 in the better eye due to refractive errors.
The magnitude of refractive errors among Nigerian children is not known. Most existing information on prevalence of refractive errors among Nigerian children is from studies among primary school children10, 42-45 and clinic-based studies 46-47 in various parts of the country. Studies conducted among Nigerian school children have reported prevalence rates ranging from 7.3%42 to 8.9%43 concluding that uncorrected refractive errors are of public health importance.
Almost all the existing information on prevalence of refractive errors among primary school children in Nigeria was from studies in urban schools 42–44. Nkanga’s10 report was on both rural and urban primary schools.
Umeh48, in a study to evaluate the causes and profile of visual loss in an onchocerciasis –endemic forest-savanna zone in Nigeria, examined
29 1, 217 subjects. Of this 374 (30.7%) had various degrees of visual loss;
5.4% were blind while the low vision rate was 25.3%. The most common cause of visual loss in children were refractive error (59.3%) followed by cataract and optic nerve disease, each with (11.1%), and sclerosing keratitis (corneal onchocerciasis) with 7.4%.
Chuka-Okosa, 49 in a cross-sectional study aimed at testing the distant visual acuity of all the pupils in a rural primary school examined a total of 305 pupils (Participation rate of 74.8%) aged 5-17 years. The prevalence of reduced distant normal acuity was found to be 0.33% when the worse eye was considered. This was as a result of a diffuse chorioretinopathy involving the macula and optic disc. No case of refractive error was found among the children.
The contribution of visual impairment in children by cataract varies from region to region ranging from 8% in established market economies to 20% in middle east crescent to 9% in sub-Saharan African.2 In
Uganda27, a total of 1135 children from birth to 15 years having subnormal vision was examined in a study to examine the causes and outcome of subnormal vision starting in childhood, to aid in planning for its avoidance and for rehabilitation. The result of this study showed that
30 14.8% had visual impairment, 6.5% severe visual impairment, 63.2% were blind and 15.2% were too young to test. Cataract was the largest cause of visual impairment (30.7%) and surgical outcome was unsatisfactory. Visual loss following corneal ulceration was the second commonest cause of subnormal vision (22.0%).
Nkanga50 in his study examined a total of 1948 primary school children in both urban and rural communities of Enugu State, Nigeria. Of the 1948 pupils examined, 177 were found to have at least one ocular problem giving a prevalence of 9.1%. The prevalence of visual impairment was 0.72%. Of these, 71.4% were caused by refractive errors, 21.4% by cataract and 7.1% by amblyopia.
In Pakistan20, the prevalence of non-vision-impairing condition
(NVIC) is 14.6%. The main NVIC were allergic conjunctivitis (3.7%) and acute/chronic dacryocystitis (12%).
In a study in Kaduna state, Nigeria51, an onchocerciasis mesoendemic area, the prevalence of eye diseases was found to be
10.36%. Of the 5,220 post primary pupils screened, conjunctivitis
(4.9%) was the commonest eye disorder followed by refractive error
(2.4%) as the second commonest. In a similar study in Kaduna by
31 Ozemela52 et al, the school eye health services of the state from 1989 to
1991 was evaluated. Infective conjunctivitis was the commonest ocular problem (15.4%) followed by vernal/allergic conjunctivitis (8.4%).
Oragwu45, in a survey of eye health status of primary school children in Enugu State Nigeria, examined a total of 3,360 eyes. Of these 343 eyes revealed ocular disorders. Vernal conjunctivitis accounted for the commonest ocular disorder 204 (59.42), followed by refractive error 99 (28.8%), amblyopia 12 (3.5%). Ukponmwan53 in a hospital based study over a 2 year period found that vernal keratoconjuctivitis was the most common conjunctival disease seen. Of the patients studied 54.1% were children.
The differences in prevalence of various eye conditions between the various studies reviewed may also be related to the visual acuity criteria used in the screening, age of the children examined, geographical location of study and the prevailing socio-economic condition of the children studied as well as the level of ignorance.
Yoloye43 in an earlier study pointed out the need for standardization of screening parameters to make comparison between studies more useful.
32 Ashaye and Samaila54 in their review noted that early detection and treatment of asymptomatic disease has emerged as a strategy to secondary prevention. Health workers can through health education play a more effective role in early detection of asymptomatic disease.
Obtaining data on blindness and blinding diseases can effectively be done through eye surveys. This survey is a response to the need to provide accurate information on the cause of ocular disorders and visual impairment in school children, in a particular locality as recommended by the Nigerian National Programme for Prevention of Blindness and therefore contribute to the prevention of blindness programme mapping of Nigeria.
33 CHAPTER 3
Materials and Method
Study Population
All the available and eligible children in the 8 primary school in
Abagana aged 6 years but below 16 years were interviewed and examined totaling 2092 subjects.
Pre-Survey Visit
Authorization was obtained from the Njikoka Local Government
Education Authority secretary and with this, the headmasters and headmistresses of the schools were approached and their consent obtained to enable individual pupils be examined. A detailed explanation was given to each school head on the contents and aims of the study including the added benefits of the immediate free treatment of those children with treatable ocular disorders or referral of more complex ocular disorders to the University of Nigeria Teaching Hospital,
Enugu for further management. An added incentive was a free ocular examination of the teachers in each school.
34 Materials
The materials used included; the standard Snellens’ chart for visual acuity, pen torch and a simple magnifying head loupe for examining anterior segment, direct ophthalmoscope for examining posterior segment, short acting dilating eye drops (0.5% Tropicamide).
A cane or long straight thin dry stick was used as a pointer during the visual acuity test.
Methods
The visual acuity was measured outdoors for each child by an ophthalmic assistant using the standard Snellens’ chart at 6 meters; children who wore glasses were examined with them. If a child read all the letters in a row of the snellens chart, that line was taken as the actual visual acuity. When visual acuity was less than 6/9, a pinhole was used. Each eye was examined separately.
Using the Modified WHO/PBL eye examination record, a trained assistant collected the required information on personal data and ophthalmic history.
The section on visual assessment, ocular examination was completed by the researcher.
35 The external eye examination was done with the aid of a pen torch and a simple magnifying head loupe. A direct ophthalmoscope was used to examine the posterior segment and where necessary for example if the visual acuity was less than 6/18 and did not improve with pin hole, and no obvious identifiable causative factor, dilated fundoscopy was done using short acting dilating eye drops (0.5%
Tropicamide). The author carried out all eye examinations.
An assessment was made of the anatomical site of ocular disorder or cause of visual loss and the likely etiology in each eye, according to the WHO/PBL criteria.
Research assistants were trained with a sample of the examination form on how to interview the pupils and measurement of visual acuity with snellens chart. Training was done using some pupils from Epupe primary school Abagana. Duration of training was for one day.
Quality Control
To ensure quality control of data collected by the assistants, the researcher reviewed the accuracy of the questionnaire filled before examining the subjects.
36 Data Management/Analysis
A modified WHO/PBL eye examination record form was completed for each child.
All data were cleaned and entered into the computer. Analysis was carried out using the SPSS 11.0 software as well as a scientific pocket calculator.
Frequency tables, charts, and diagrams were used to construct the distribution and percentages of ocular disorders, visual acuity, visual loss and other attributes among different age groups, and sex. Comparison of percentages was done using Chi- square test.
Ethical Consideration:
The study was carefully explained in the local language to all participants and only those who gave their voluntary consent were studied. A written consent was however obtained from the headmasters/headmistresses of the schools. Ethical clearance for the study was obtained from the Ethical committee of the University of
Nigeria Teaching Hospital, Enugu.
37 Study Definitions
Blindness:
Blindness is defined as visual acuity in the better eye of less than
3/60 with best correction. This corresponds to categories 3, 4 and 5 of
WHO categories of visual impairment. Monocular blindness is visual acuity 0f less than 3/60 in one eye with best correction with the second eye not equally blind.
Low Vision
The person with low vision is one who has impairment of visual functioning even after treatment and/or standard refractive correction, and has a visual acuity of less than 6/18 to light perception in the better eye, but who uses, or is potentially able to use, vision for the planning and/or execution of a task for which vision is essential.
Categories of Visual Impairment
The WHO category of visual impairment was used to classify visual impairment in this study. Table 2.
38 Table 2: WHO CLASSIFICATION55 OF VISUAL IMPAIRMENT
Visual Visual Acuity with best correction impairment Category Maximum less Minimum equal to or better than than 1 6/18 6/60 low vision 2 6/60 3/60 Low vision 3 3/60 1/60(Cf at 1m) 4 1/60 Light perception Blindness 5 NPL (No perception of light 6 Undetermined or unspecified
Childhood:
The United Nation Children’s Education Fund (UNICEF) definition of childhood as the period of life before 16 years of age was used in this study.
Eligible pupils or school child:
A pupil or school child was considered eligible in this study if the child is up to 6 years but not yet up to 16 years.
39 Refractive Error:
Visual acuity less than 6/9 improves with the pinhole.
Chorioretinal disorders:
These are lesions of the choroids and the retina .
Treatable conditions:
These are ocular conditions that could be treated surgically, optically or medically.
Preventable Lesions:
Lesions that could be prevented from occurring by a reasonable deployment of skills and resources are defined as ‘preventable’ for example corneal opacity resulting from measles which could have been prevented with adequate immunization.
Amblyopia:
Amblyopia is considered to be the cause of visual loss if there is unilateral or bilateral reduced visual acuity which is not alleviated by correction of any refractive error or treatment of any pathological defect that forms an obstacle to the formation of a clear retinal image.
40 CHAPTER 4
Results
Out of 2336 primary school pupils, 2092 aged 6 - 16 years were examined. Out of the 244 not examined 62 though eligible were absent from school on the day of visit. On a repeat visit 14 was said to be receiving treatment at home for febrile illness. Reason for the absence of the remaining 48 was not known. However 182 were excluded because of ineligibility due to age. This makes the total number of eligible pupils to be 2154 with a coverage of 92.21%.
More males 1081(51.7%) than females 1011(48.3%) constituted the sample population giving a male/female ratio of 1.07 to 1, (p
=0.0013).
Figure 1 shows that the 6 - 10 years age group constitutes 52.7% of the subject population
41
600
500
400
300
Number of pupils pupils of Number
200
100
0 6 - 9 10 - 13 14 - 16
Fig 2: AGE AND SEX DISTRIBUTION OF THE STUDY SUBJECTS
(n = 2092)
Male Female
42 Visual Acuity and Visual Loss.
(a) Visual acuity distribution .
Of the 2092 school children examined 2086(99.7%) had a visual acuity of > 6/18 in the better eye, while 6 (0.3%) had a visual acuity of < 6/18 in the better eye, (table 3)
TABLE 3: DISTRIBUTION OF PUPILS BY VISUAL ACUITY IN THE BETTER EYE.
Visual acuity Number of pupils Percentage(%) 6/6 – 6/9 2082 99.5 6/12 – 6/18 4 0.2 <6/18 – 6/60 6 0.3 Total 2092 100
Table 4 shows the causes of low vision amongst the study subjects with
amblyopia contributing up to 50% of the cases.
43 TABLE 4: CAUSES OF LOW VISION AMONGST THE STUDY SUBJECTS
Ocular disorders Visual acuity Percentage < 6/18 – 6/60 (%) Amblyopia 3 0.2
Macular chorioretinal scar 1 0.1 (ocular toxoplasmosis)
Albinism 1 0.1
Congenital glaucoma 1 0.1
Total 6 0.5
Amongst the 2092 school children examined 4 (0.2%) had visual acuity of < 3/60 in one eye, which corresponds to monocular blindness.
These were caused by a case each of congenital glaucoma, traumatic cataract, optic neuropathy, and macular chorioretinal scar.
b) Distribution of Ocular Disorders Amongst The Study Subjects
Of the 2092 school children seen 127 had ocular disorders of various types, (table 5) some occurring bilaterally. Vernal conjunctivitis was the commonest making up 48.0% of all ocular disorders. The second commonest was refractive error (11.01%).
44 TABLE 5: DISTRIBUTION OF OCULAR DISORDERS AMONGST THE STUDY SUBJECT
Ocular disorders Number of Pupils Percentage Anterior segment Vernal conjunctivitis 61 48.1 Subconjunctival haemorrhage 9 7.1 Infective conjunctivitis 3 2.4 Benign conjunctival tumour 3 2.4 Pterygium 1 0.8 Ptosis 8 6.2 Stye 5 3.9 Preseptal cellulitis 2 1.5 Zeis cyst 1 0.8 Carbuncle 1 0.8 Corneal opacity 3 2.4 surgical iridectomy 1 0.8 Traumatic cataract 1 0.8 Posterior segment Macular chorioretinal scar 2 1.5 Congenital cataract 1 0.8 Traumatic Optic neuropathy 1 0.8 Whole globe/muscles Refractive error 14 11.0 Albinism 1 0.8 Amblyopia 6 4.7 Squint 3 2.4 Total 127 100
The disorders were commoner in males, 75(59.06%) than in females
52(40.94%) giving a male/female ratio of 1.44 to 1. Children within the age group 10 to 13 accounted for 48.03% of the ocular disorders, (table
6).
45 TABLE 6: DISTRIBUTIONS OF OCULAR DISORDERS SEEN IN THE STUDY SUBJECTS BY AGE (n = 2092) Total (%) Ocular disorders Age 6 – 9(%) 10 –13(%) 14 -16(% Anterior segment Vernal conjunctivitis 27 (21.3) 31 (24.4) 3 (2.4) 61(48.1) Subconjunctival 7(5.6) 2(1.5) - 9(7.1) haemorrhage Dermoid cyst 1(0.8) 2(1.5) - 3(2.4) Infective conjunctivitis 2(1.5) 1(0.8) - 3(2.4) Pterygium - 1(0.8) - 1(0.8) Ptosis 5(3.9) 1(0.8) 2(1.5) 8(6.2) Stye 4(3.1) 1(0.8) - 5(3.9) Preseptal cellulitis - 2(1.5) - 2(1.5) Zeis cyst - 1(0.8) - 1(0.8) Carbuncle - 1(0.8) - 1(0.8) Corneal opacity 1(0.8) 2(1.5) - 3(2.4) Surgical iridectomy 1(0.8) - - 1(0.8) Traumatic cataract - 1(0.8) - 1(0.8) Posterior segment Macular chorioretinal - 2(1.5) - 2(1.5) scar(ocular toxoplasmosis) Congenital glaucoma 1(0.8) - - 1(0.8) Traumatic Optic - - 1(0.8) 1(0.8) neuropathy Whole globe/muscles Refractive error 6(4.7) 6(4.7) 2(1.5) 14(11.0) albinism 1(0.8) 1(0.8) Amblyopia 1(0.8) 5(3.9) - 6(4.7) Squint 2(1.5) 1(0.8) - 3(2.4)
Total 58(45.8) 61(48) 8(6.2) 127(100)
46
C) Anatomical Site of Ocular Disorders. Figure 3 shows the distribution of the identified ocular lesions by
anatomical site. Lesion on the conjunctiva constituted 66.8% of all the
lesions.
FIG 2: ANATOMICAL SITE OF OCULAR DISORDERS IN THE AFFECTED EYES OF THE STUDY SUBJECT.
47 As regards the underlying causative factors, postnatal/infancy/childhood factors were at play in 102(80.3%) cases of ocular disorders while
22(17.3%) cases were due to undetermined factors. Intrauterine factors were responsible for 2 (1.6%) while 1(0.8%) were due to hereditary disease.
Preventable and Treatable Disorders.
Among the 209 eyes with ocular disorders, 33(15.7%) eyes had preventable disorders, while all 209 had treatable disorders.
48 TABLE 7: CLASSIFICATION OF OCULAR DISORDERS IN THE AFFECTED EYES OF THE STUDY SUBJECT INTO PREVENTABLE AND TREATABLE DISORDERS
Ocular disorders Preventable Treatable(%) (%) Vernal conjunctivitis 122(58.4) Refractive errors - 21 (10) Subconjunctival 9 (4.2) 9 (4.2 haemorrhage Ptosis - 10 (4.8) Amblyopia 12 (5.8) Stye - 5 (2.4) Squint - 3 (1.4) Benign conjunctival - 3 (1.4) tumor Infective - 5(2.4) conjunctivitis Corneal opacity 4 (1.8) 4(1.8) Macular chorioretinal 3 (1.4). 3(1.4) scar Presepal cellulites - 2 (1.0) Albinism 2(1.0) 2 (1.0) Congenital glaucoma 2 (1.0) Pterygium - 1 (0.5) Zeis cyst - 1 (0.5) Carbuncle - 1 (0.5) * Traumatic cataract 1 (0.5) 1 (0.5) Traumatic Optic 1 (0.5) 1 (0.5) neuropathy* * surgical iridectomy 1 (0.5) 1 (0.5) Total 33 (15.7) 209 (100)
* THESE ARE SECONDARY TO TRAUMA
49
CHAPTER 5
Discussion
Comparison between studies is difficult because in the same or similar localities, the age groups studied were different. In Nkanga’s50 study the age group studied was 7 to 18 years while the school population was both rural and urban. In this study the age group studied was 6 to 16 years and the school population was entirely rural.
The age group with the lowest number of school children was 14 to 16 years comprising 3.7% of the population studied. In a similar study by Oragwu45, this age group constituted the lowest number of the children studied making up 5.2% of the sample population studied.
However these numbers are high because this age group ought to be in the secondary school. This could be as a result of the fact that both studies were done at entirely rural setting where poverty, ignorance and altered priorities may result in late entry of the children into formal schools even though primary school education is free in Abagana. It may also be due to late graduation from school as a result of factors that may extend the period of study or interrupt education temporary
50 such as loss of either or both parents. In addition there is generally low male enrolment in schools in Igbo land.
Limitations and constraints in this study are mainly the inability to check night blindness due to logistics and also the issue of funding.
Most of the children were found to have normal vision in this study. This may be attributed to the absence of environmental factors that may lead to blindness in children for example trachoma and vitamin
A deficiency. However, even though onchocerciasis is endemic in
Anambra state, no case was found in this study.
The 0.5% prevalence of visual impairment found in this study is lower than Nkanga’s50 0.72% in his study earlier among primary school children. Yoloye43 in Ibadan, defining visual impairment as visual acuity of <6/9 to 3/60, found the prevalence of low vision to be 7.4%. In the study of visual impairment in primary and post primary school children by Onyekwe56 et al, prevalence of visual impairment of 4.1% was documented. Onyekwe et al defined visual impairment as visual acuity of <6/18 to 3/60.
The different results from the various studies mentioned may be due to the different study areas, different age groups and the definition
51 visual impairment in each study. Onyekwe56 combined both primary and secondary schools subjects in his study. Yoloye’s43 definition of visual impairment as visual acuity of <6/9 to 3/60 will tend to produce a higher prevalence of visual impairment when compared with this study.
There is therefore need to standardize parameters used for school vision testing in Nigeria. One of the ways this can be done is by using the
UNICEF definition of childhood for age eligibility and the WHO definition of visual impairment for school vision testing, which was used in this study.
The contribution of amblyopia (which is preventable) in this study were high. Early detection of amblyogenic ocular conditions and prompt intervention will prevent or reduce the prevalence of amblyopia as a cause of visual impairment. This relative high prevalence may be related to the purely rural setting of both studies. In these rural communities, there is reduced awareness coupled with poor availability of ophthalmic services. Parents are unable to effectively take care of their children’s ocular complaints. At the time of this study there is no ophthalmologist or optometrist in the entire local government area. Only one trained ophthalmic nurse at Abagana is available in the entire local government
52 area. This means that even where ocular complaints were made, inexperienced personnel at the rural health centers and traditional healers were called to treat, thereby increasing the prevalence of conditions such as amblyopia which usually result from non-intervention, inappropriate or delayed intervention.
By WHO definition, no case of blindness was found in this study.
In Nkanga”s10 study, the prevalence of blindness was found to be
0.05%. This low prevalence is in keeping with the global low prevalence of blindness in children.57 There are about 1.5 million severely visually impaired and blind children worldwide.57 This is relatively small compared with the 17 million adults blind due to cataract alone.57
Other possible reason for the absence of blind children in this study is the fact that most blind children will be in schools for the blind.
There are at least 3 schools for the blind in southeast Nigeria located at
Oji River (Enugu state), Isulo(Anambra state) and Umuahia(Abia state) .
It may also be likely that the blind is being hidden at home as blindness may constitute a stigma to the family. Stigmas and cultural taboos are known to be prevalent in the rural areas and this is a rural community.
53 However, in this study 4(0.2%) out of the 2092 children examined had visual acuity of <3/60 in one eye, which corresponds to monocular blindness. These were caused by congenital glaucoma, traumatic cataract, optic neuropathy resulting from blunt trauma to the brow, and macular chorioretinal scar, each contributing a case. In Oragwu’s45 study, 3(0.18%) cases of monocular blindness were due to traumatic cataract, phthisis bulbi and squint. Trauma was responsible for 50% of the cases in this study and 100% of the cases in Oragwu’s45 study. This suggests that simple preventive measures that reduce the occurrence of ocular injuries may significantly reduce the prevalence of monocular blindness in childhood in the area studied.
This study found ocular disorders to have a prevalence of 6.1%.
The prevalence of ocular disorders found in this study is lower than that obtained in the previous studies by Nkanga10, Yoloye43, Bhar and Abiose51. This may be due to the difference in study areas and the period of study as some ocular disorders have seasonal variability. It may also be a reflection of improved health care delivery over time.
There are 2 community- based health facilities (comprehensive health centers) each located in Abagana and Ukpo all within the old Njikoka
54 LGA owned by the University of Nigeria Teaching Hospital Enugu and the Nnamdi Azikiwe University Teaching Hospital Nnewi respectively.
Their general health intervention such as immunization, school health visit, health education among other health activities may have been responsible for the lower prevalence of ocular disorders found in this study. Nwosu58 in a population survey of childhood eye diseases in
Anambra state documented that there was no child with a previous history of measles. In addition the ophthalmic nurse at the
Comprehensive Health Center Abagana participates in the school health visits. Her input might have specifically reduced the prevalence of ocular disorders recorded in the study. This implies that more specific intervention that will address preventable causes of visual impairment such as amblyopia will further reduce the prevalence of the ocular disorders.
In this study more males than females had ocular disorders. This may be related to the fact that more males than females were examined in a ratio of 1.07 to 1. Also the influence of trauma, which is known to be more prevalent in males, may have been contributory.
55 The commonest ocular disorders identified were vernal conjunctivitis, followed by refractive error. In Nkanga’s50 study the order was reversed as the commonest cause was refractive error followed by vernal conjunctivitis.
Vernal conjunctivitis, although the most common, however, as expected did not contribute to visual impairment. In vernal conjunctivitis
Visual loss could be as a result of coneal involvement due to punctate keratopathy, pannus formation etc as well as self-medication with steroids or traditional medication. Besides, the affected children stay out of school frequently to visit the hospitals for treatment, which may adversely affect their academic performance. Furthermore, Chuka-
Okosa59 in her study reported that children with vernal conjunctivitis stayed away from school for several days or even weeks. Sometimes the children are sent home from school by their teachers who believe the problem is infectious. Education of teachers, parents and children on the nature of the disease and potential complication is important to minimize misconception and mismanagement.
Of the 127 ocular disorders seen in the sample population
16(12.6%) resulted from trauma, which is preventable, with a male to
56 female ratio of 3:1. Trauma contributed 50% of the causes of monocular blindness amongst the sample population and all were males.
This male preponderance was not unexpected since other studies of childhood injuries have shown more males than females affected.
Olurin32 in her study found a male preponderance and most children had their injuries at play. In Umeh’s study17 the male/female preponderance was 2:1 and 16% of those studied had these injuries as schoolroom accidents and 23.7% occurred at play or sports. This is due to the fact that males are more likely to be aggressive during play or sports.
Strategies for the prevention of eye injuries recommended by
Onwasigwe and co-workers36 are mainly health education, improved supervision of children at play and change in the method of corporal punishments. The first of these is a function of the public health department of ministry of health. The last two would require the attention of educational policy formulators and school teachers.
Most of the curable and preventable ocular disorders were due to factors for which interventional programmes could be applied. For instance the monocular blindness from cataract though traumatic is
57 curable surgically while amblyopia could be prevented by early detection and treatment.
From this study, the common ocular disorders amongst children in
Abagana were identified, together with the common causes of visual impairment. This means that those affected and those at risk are known, so that specific preventive and intervention measures can be planned for the community.
Although the need for periodic vision screening has been emphasized by all studies, this has not been implemented. Reasons for non-implementation include lack of adequate number and cadre of ophthalmic personnel, lack of funds and lack of appropriate ophthalmic knowledge. Unfortunately, these reasons also hold true in this rural area. The effects of all these is that although the prevalence of ocular morbidity in this study is lower than in previous studies it is still unacceptably high.
As Ozemela60 pointed out, politicians do not pay much attention to eye disorders and concentrate more on what they consider life threatening and what they consider more vote-catching programmes such as maternity and child health centers. The result of this is
58 insufficient fund available to organize trainings, for community Health
Extension worker (CHEW). Suggestions by Babalola61 on cost recovery systems to overcome the problem of funding for primary eye care services have not been implemented. This implies that even though primary eye care is an integral component of the primary health care system in Nigeria, there is still much room for the improvement of its functioning.
With the above state of affairs it is therefore not surprising that when the results of this study are compared to Nkanga’s50 study which was done about 10 years ago in a similar rural community in Enugu one can conclude that there is no significant improvement in the ocular health status of primary school children.
Unless more emphasis is placed on making both the children, the parent, guardians or adults (especially teachers) know the importance of ocular health and the potential complications associated with ocular disorders, school vision testing would continue to have a limited impact on ocular eye health of school children. The way forward could be drawing up a school vision-testing programme for each state and for each local government area, taking local peculiarities into consideration.
59 There is need to make relevant research findings available to local health policy makers and health care providers who are more sensitized to local peculiarities. This could encourage local government authorities to make the few CHEWs they have into better-trained integrated eye care workers, through seminars, workshops and courses. Non-
Governmental organizations may also contribute by paying more attention to childhood ocular disorders and visual loss as the cornerstone of the child preventive and promotive ocular health care.
This can be done through provision of funds, infrastructures and training of human resources. This is in keeping with the Ottawa Charter62 which is an international action document aimed at global health promotion through provision of prerequisites for health for example peace, shelter education, food etc, advocacy and coordinated action by all concerned.
This will increases the chances of study findings being implemented and making a practical difference in the area studied.
60 CHAPTER 6
6.1 Conclusion
This study found a prevalence of 6.1% of ocular disorders amongst the primary school children in Abagana.
This study also showed that most cases of visual impairment are avoidable being curable or preventable.
The commonest cause of visual impairment was amblyopia, which is preventable.
Vernal conjunctivitis was the commonest ocular disorder found followed by refractive error. None of these contributed to visual impairment.
Infective disorders are not important causes of visual impairment in this area.
6.2 Recommendation
The recommendations arising from this study suggest ways of improving the ocular health of primary school children in Abagana. The recommendation may also with slight modification be applicable in other
61 neighbouring/contigous communities with similar problems and environment.
1. Parents
Eye health education to the parents via information avenues such as churches, annual community women gathering popularly known
“August meeting” and the markets will facilitate early detection of ocular disorders by the parents, which in turn will result in early intervention.
In addition, information on immunization and nutrition will help reduce the incidence of preventable causes of blindness such as measles and vitamin A deficiency.
2. School Authorities
The school teachers should be enlightened on the common ocular problems or disorders in their local area by eye care specialists through health publication, seminars, workshops and interaction with local and state government health policy makers and providers.
62 3. The state and local government area authority
(i) The local government education authorities (LGEAs) in collaboration with the state government should be encouraged to co- ordinate primary eye care activities between schools authorities in their local government areas and the state and federal education boards.
(ii) LGEAs should ensure adequate co-operation with local government health authorities so that simple ocular skills such as identifying children with ocular disorders to see eye care personnel are done on the basis of appropriate skill and knowledge.
4. National organization and institutions
There is a need to encourage the training of paediatric ophthalmologists, optometrist, and orthoptics so that ocular health needs of children can be effectively managed at the highest level.
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72 73 CONSENT FORM INTRODUCTION
Your school and pupils have been selected to participate in a community based survey project aimed at evaluating the ocular health status of primary school children in rural communities. The project will help in identifying the causes of ocular disorders, which will help in planning interventional programmes in reducing childhood ocular morbidity and blindness.
VOLUNTARY NATURE OF PARTICIPATION
Participation in this project is completely voluntary. Thus although your pupils have been selected, they are free to participate in the programme or decide otherwise. If you decide to participate, you are free to withdraw your pupils at any stage of the programme without any reprisal.
STUDY PROCEDURE
The child will be asked some questions such as age, history of previous eye disease and history of any current eye complaints. Thereafter, both eyes of the child will be examined with the aid of snellen’s visual acuity chart, anterior segment with pen torch and magnifying head loupe and in selected cases the posterior segment with direct ophthalmoscope after adequate pupillary dilatation with 1% cyclopentolate eye drops(a short acting dilating agent).
74 Risks Any child with a moderate to severe visual loss that did not improve with the pinhole test will have their pupils dilated with 1% cyclopentlate eye drops. This may cause a moderate blurring of vision.
FEEDBACK
The researcher will be at hand every time to answer any questions you may have concerning the project. Similarly, few days after each visitation, the research team will be available in the school to answer any question or deal with any problem that may arise from the study. You can reach the researcher on 08037007163 or at the department of ophthalmology university of Nigeria teaching hospital Enugu.
RESPONSE
I have read an understood the above. Also all gray areas has been clarified. I fully understand the nature, risk and benefits of the study and hereby consent to allow my pupils take part in it.
______Name and signature of subject Name and signature of Researcher
Date______Date:______
______Name and signature of Witness Date:______
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