|Year : 2011 | Volume
| Issue : 4 | Page : 473-476
Ocular disorders in children in Zaria children's school
ER Abah1, KK Oladigbolu1, E Samaila1, A Gani - Ikilama2
1 Department of Ophthalmology, Ahmadu Bello University Teaching Hospital, Shika, Nigeria
2 Hope for the Blind Foundation, Wusasa, Zaria, Nigeria
|Date of Acceptance||23-Oct-2011|
|Date of Web Publication||12-Jan-2012|
E R Abah
Department of Ophthalmology, Ahmadu Bello University Teaching Hospital, Shika, Zaria
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: The main causes of blindness in children change over time. The prevalence and pattern of eye diseases in children were studied in northern Nigeria 6 years ago. This study like the previous one was a school eye health screening conducted in Zaria children school located at the centre of Zaria, a city in northern Nigeria.
Aims and Objectives: to determine the current prevalence and pattern of eye diseases affecting school children in Zaria. This is to serve as a current template for planning eye care for children in Zaria and environs.
Materials and Methods: a cross sectional study of 327 children who completed a pre-designed school eye screening format was conducted. Consent was obtained from the school authority and the parents before the screening exercise. It involved assessment of visual acuity, anterior and posterior segment examination and colour vision testing. Intraocular pressure measurement and refraction were done for those with indications.
Result: A total of 327 children were examined, out of which 45.6% (n=149) were males and 54.4% (n=178) were females. M: F=1:1.2. Age range 5-17yrs with mean of 9.6 ± 3.1(SD). The commonest causes of eye disorders were refractive errors 8.0% (n=26), allergic conjunctivitis 7.3 % (n=24), glaucoma suspects 3.7% (n=12) and colour deficiency 1.5%(n=5).
Conclusion: The major causes of childhood eye disorders were uncorrected refractive errors and allergic conjunctivitis. The predominance of uncorrected refractive error is similar to what is obtainable in other parts of the world especially in the urban areas.
Keywords: School Children, Ocular disorders, Zaria
|How to cite this article:|
Abah E R, Oladigbolu K K, Samaila E, Gani - Ikilama A. Ocular disorders in children in Zaria children's school. Niger J Clin Pract 2011;14:473-6
| Introduction|| |
School eye health screening is necessary for the following reasons:
- There are 1.4 million blind children in the world and out of which 300,000 are in Africa. 
- The children have a lifetime of blindness ahead of them with an estimated 75 million blind years. This is second only to age-related cataract. 
- Amblyopia develops if visual disorders in children are not managed promptly. 
- In developing countries, 60% of children die within a year of going blind. 
- The main causes of blindness in children change overtime. 
- Children do not readily articulate their problems and therefore, periodic screening remains a major option. 
Children should receive prompt and proper eye care in order to avoid vision-threatening problems, which could affect their learning ability, personality and adjustments in school. , The complaints related to these eye morbidities may originate from the children themselves, parents or even teachers. 
The primary school setting serves as a ready pool for interventions with respect to childhood blindness which is a vision 2020 priority. 
The age range of those in primary school also falls into one of the stages recommended by American Academy of Ophthalmology and American Association of Paediatric Ophthalmology and Strabismus for examination of children's eyes (new born nursery, six months, three years, five years and older).  This is applicable to developing countries as part of vision 2020 action plan which encourages fundus examination as early as four to six weeks after birth for infants at risk.  The spectrum of ocular problem varies from country to country and even from region to region in the same country. 
| Materials and Methods|| |
A descriptive, cross-sectional study of 327 children from Zaria Children's School, a school located within Zaria G.R.A, was conducted. The school was purposively selected because of diverse population. It has three sections: nursery, primary and junior secondary. All the children from these sections were included in the study except those who were either absent or whose parents did not give consent. Written permission from the school authority and informed consent from parents were obtained prior to the screening exercise. Pre-designed school eye screening formats drawn up by the authors to extract information on bio-data, general medical and ocular history and also document vision screening were distributed to various class teachers. The formats were completed with the help of the parents and class teachers a day before the screening.
The students were assessed within the school premises by a team of three ophthalmologists and three staff of "Hope for the Blind Foundation". Anterior and posterior segments of the eyes were examined by the ophthalmologists using pen torch, direct and indirect ophthalmoscope. They also carried out color vision testing on the students using Ishihara chart. The visual acuity of the students for distance and near were tested by three trained staff of the foundation using the conventional Snellen's chart and reduced Snellen's chart respectively. They were trained and tested by the ophthalmologists until they were certified as capable of performing these tests.
The children who had visual acuity of 6/9 or worse but improved with the use of pin hole were refracted with a streak retinoscope. Refractive error was defined as any error of 0.5 diopters or more in one or both eyes. Allergic conjunctivitis was defined as recurrent itching, conjunctival injection/brownish discoloration with or without limbal follicles.
Tonometry was done for children with suspicious cup disc ratio, defined as cup disc ratio of 0.5 or more or asymmetry of >0.2, using Perkin's applanation tonometer after instilling 1-2 drops of proparacaine hydrochloride 5 mg/ml.
| Results|| |
A total of 327 students were examined. Their age range was between 5 and 17 years with a mean of 9.6 years ± 3.1 (SD). Males constituted 45.6% (n=149) and females 54.4 % (n=178). The M: F ratio was 1:1.2 [Figure 1].
Out of the total sample, 324 had unaided visual acuity between 6/4 and 6/18 (no visual impairment), but 3 children had visual acuity between 6/24 and 6/60 (visual impairment) - [Table 1] and [Table 2].
The prevalence of ocular disorders in this study population was 22.6%.
The most common disorder was uncorrected refractive error prevalence (8.0%, n=26) with hypermetropia leading. Prevalence of spectacle use was 3.1%. This was followed closely by allergic conjunctivitis, prevalence = 7.3% (n=24).
The prevalence of glaucoma suspects was 3.7% (n=12). One child had asymmetry of CD ratio > 0.2 while the others had CD ratio > 0.6 in both eyes. Two children had intra ocular pressure > 21mmHg.
Color vision deficiency was the next with a prevalence of 1.5% (n=5). Three children had red - green defect and two had red - blue color defects.
One child was a known sickler who had a tinge of jaundice but no fundal changes. Other abnormalities found include unilateral hyaloid artery remnant, bilateral optic neuropathy, moderate bilateral congenital ptosis, and a convergent esotropia, [Table 3] and [Table 4].
None of the children had the typical nutritional corneal opacity. No case of infective conjunctivitis was seen.
| Discussion|| |
The prevalence of ocular disorders in this study group was 22.6%. This was much higher than the 8.4% reported six years ago in this part of the country by Kehinde.  However, Ajaiyeoba  in a study amongst students of south western Nigeria reported a prevalence of 15.5%. The high prevalence of eye disorder can be attributed to a relative increase and the prevalence due to the higher sample size in the previous study or a true rise in prevalence of eye disorders.
The WHO recommended level for visual impairment of less than 6/18 in the better eye  was used in this study. Only 1% had visual impairment. The slightly higher level in females is probably because females were more in the sample population. The higher level between the ages of 6-15years was because most of the children fell within this age bracket.
The prevalence of uncorrected refractive error in this study was 8.0 %. There is a significant rise as compared to 1.7% earlier documented by Kehinde.  This is attributable to the fact that Zaria is an urban setting where prevalence of uncorrected refractive error is likely to increase. In South East Asia, the prevalence of myopia has increased dramatically among children particularly in urban areas.  In addition, it has been found that globally, uncorrected refractive error is the main cause of visual impairment in children aged 5-15 years.  In our study, 92% were in this age bracket. In south - western Nigeria, Ajaiyeoba  documented a prevalence of 5.8% for uncorrected refractive errors. Faderin  also reported a prevalence of 7.3% for uncorrected refractive error in primary school children of south western Nigeria with hypermetropia predominating. The findings of this study were similar to ours. The prevalence of uncorrected refractive error among Chinese children of school age was found to be 20.7 by Lian et al.  It is not unusual because the prevalence of uncorrected refractive error in South East Asia is quite high.  Allergic conjunctivitis was the next common in our study with a prevalence of 7.3% as compared to 4.5% earlier documented in our settling. Several studies in Nigeria have documented the high prevalence of allergic conjunctivitis in children. ,,, It is less common in temperate countries where it is usually seen in higher frequency during the warm summer months. 
Glaucoma suspects constituted 3.7%. This was relatively high compared to the findings in south western Nigeria by Ayanniyi,  (0.8%) six years ago. The prevalence may have risen over the years or originally high in this part of the country. The earlier study in northern Nigeria did not document this.
Similarly color deficiency was not documented in the previous study but we found a prevalence of 1.5% (n=5) in our study. Out of these, three had red-green defect and 2 had red-blue color deficiency. Tabansi  reported a lower prevalence of 2.6% in primary school children of southern Nigeria.
Corneal scars/opacities were not seen in this study probably because it is an enlightened population that has complied with the EPI (expanded program on immunization) program and vitamin A distribution. As a consequence of child survival programs (e.g., integrated management of childhood illness), corneal scarring due to measles and vitamin A deficiency is declining in many developing countries. 
Infective conjunctivitis was also not documented, probably because of good personal hygiene. The fact that it is an enlightened population is also likely to have contributed.
Other ocular abnormalities such as molluscum contagiosum, squint, hyaloid artery remnant and optic atrophy [Table 3] and [Table 4] were seen in insignificant numbers in both studies.
| Conclusions|| |
The major causes of childhood eye disorders were uncorrected refractive errors and allergic conjunctivitis. The predominance of uncorrected refractive error is similar to what is obtainable in other parts of the world especially in the urban areas.  Corneal opacities / scar and infective conjunctivitis are on the decline probably due to the positive impact of immunization against measles and vitamin A distribution. This must have resulted in a decline in the incidence of measles and vitamin A related keratopathy.
Similar to the findings of Nwosu.  in south western Nigeria, the major eye disorders in school children of Zaria are largely treatable or preventable.
This study was designed to serve as a current template for children's eye care in Zaria metropolis and environs.
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[Table 1], [Table 2], [Table 3], [Table 4]
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