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 Table of Contents  
Year : 2018  |  Volume : 25  |  Issue : 3  |  Page : 161-165

Visual status of special needs children in special education schools in Calabar, Cross River State, Nigeria

Department of Ophthalmology, University of Calabar; Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, Cross River State, Nigeria

Date of Web Publication26-Sep-2018

Correspondence Address:
Ernest Ikechukwu Ezeh
University of Calabar Teaching Hospital, Calabar, Cross River State
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/npmj.npmj_46_18

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Objective: The objective of this study was to determine visual status of children with special needs attending special schools in Calabar, Cross River State, Nigeria. Subjects and Methods: A cross-sectional study of all children with special needs attending special education schools in Calabar Municipal Local Government Area, Cross River State, was performed. Data were obtained using interviewer-administered questionnaires on the caregivers and ocular examination of the children which included visual acuity, refraction, ocular alignment and motility tests and funduscopy. Data analysis was performed using the Statistical Package for the Social Sciences version 20. Results: A total of 161 children with special needs out of the 176 enrolled were examined yielding a 91.5% response rate. The male-to-female ratio was 1.2:1. Their age range was 5–17 years with the mean age of 12.9 ± 3.3 years and a modal age group of ≥13 years. Twenty (12.4%) had visual impairment (VI). Uncorrected refractive error accounted for 12 (60%) of the VI. Children with learning disability (odds ratio [OR]: 3.28 and 95% confidence interval [CI]: 1.73–6.36) and developmental disability (OR: 1.90 and 95% CI: 1.10–3.20), respectively, had significantly higher occurrence of VI. Of the 161 children examined, only 11 (6.8%) have had their visual status assessed in the past. Conclusion: Children with special needs had higher prevalence of VI; however, only a few have had an assessment of their visual status in the past.

Keywords: Aphakia, developmental disability, learning disability, refractive error, special needs, visual impairment

How to cite this article:
Ezeh EI, Ibanga AA, Duke RE. Visual status of special needs children in special education schools in Calabar, Cross River State, Nigeria. Niger Postgrad Med J 2018;25:161-5

How to cite this URL:
Ezeh EI, Ibanga AA, Duke RE. Visual status of special needs children in special education schools in Calabar, Cross River State, Nigeria. Niger Postgrad Med J [serial online] 2018 [cited 2022 Dec 6];25:161-5. Available from: https://www.npmj.org/text.asp?2018/25/3/161/242204

  Introduction Top

Vision, which is the primary function of the eyes, plays a fundamental role in the acquisition of skills such as language, interpreting facial expressions and skills requiring hand–eye coordination.[1] It plays an important role in the development and functioning of a child. For children with special needs, vision has been noted to play an integral role in the psychosocial development of the child as well as compensates for certain impaired functions,[2],[3] particularly in children with hearing impairment.[4] In every child, much of knowledge and skills are obtained through the senses of sight and hearing.[4] When one of these is seriously impaired, the other is used to compensate. As the degree of impairment increases in one sense, the role of the remaining sense becomes progressively more significant.[5] For example, the deaf child may compensate by making greater use of the eyes; hence, even a mild refractive error may reduce visual efficiency as well as the overall functionality of the child.[4],[5] Any unrecognised and untreated oculo-visual abnormality in children with special needs may adversely affect their development, psychosocial behaviour and learning potentials, to a very large extent, therefore, adding further socioeconomic burden on the family.[1],[6] Similarly, the persistence of an untreated oculo-visual abnormality would exponentially aggravate the impact of other forms of disability.[7] Furthermore, if a child continues to have an uncorrected visual deficit beyond the age of 10–12 years, the plasticity of the visual system is lost, and the recovery of vision can be limited.[8] Hence, the need for a timely and comprehensive oculo-visual assessment in this group of vulnerable children.

Children with special needs are at a higher risk of ocular and visual problems than their peers.[2],[3],[9] However, they often cannot communicate symptoms adequately. Frequently, these children with special needs who have oculo-visual problems may be unable to express the presence of symptoms.[2],[7] They may receive various interventions through their schools systems (special education schools) including occupational, physical and/or speech therapy, but in most cases, they do not receive a comprehensive eye and vision examination.[7] Therefore, it is important for the professionals who treat these children to be aware of the possible ocular and visual disorders that are frequently present.

  Subjects and Methods Top

Sample size determination

The total population of children with special needs attending special education schools in Calabar, Cross River State is as given below:

  • Hillcrest special education centre: 51 children
  • Greenland special education centre: 11 children
  • Government special education school: 114 children
  • Total (N): 176 children.

The sample size is calculated using the formula:


n = The desired sample size (when population <10,000)

z = Standard error of the mean which corresponds to 95% confidence level (1.96)

p = prevalence of ocular disorders in children with special needs in Port Harcourt (76%)[10]

q = 1 − p

d = Precision with which Pis determined 0.05

n ≈ 280

For finite population (population <10,000)

nf = n/1+ (n/N)

nf = 280/1+ (280/176)

nf = 108

Allowing for 10% attrition, minimum sample size becomes 119.

Institutional ethical approval was obtained from the Health Research and Ethics Committee (HREC) of University of Calabar Teaching Hospital, with protocol number: UCTH/HREC/33/253 and dated 11th September, 2014. Permission for the study was further obtained from the State Commissioner for Education. A cross-sectional observational study was conducted from 3rd February to 28th April, 2015. One hundred and seventy-six school-age children (5–17 years) attending the three special education schools in Calabar, Cross River State, were consecutively recruited for the study. These were two privately owned special schools; Hillcrest Special education centre and Greenland Special education centre and a Government-owned (Public) special school and Government Special education school. We adhered strictly to the United Nations Convention on the Rights of Persons with Disabilities,[11] particularly articles 7, 10, 21–26 and 31 as well as international ethical guidelines for biomedical research involving vulnerable subjects – guidelines 13, 14 and 15.[12] Written informed consent was obtained from each child's parent or guardian, through the school authority, before enrolment into the study. The willing cooperation (assent) of the child was also sought, after the child had been informed to the extent that the child's maturity and intelligence permitted.

Depending on the child's resolution or recognition ability, the optometrist assessed the presenting visual acuity using appropriate chart (Tumbling E chart at 6 m distance or Lea symbols chart or Teller acuity cards held at 40 centimetres) for age and intellectual maturity. Refraction was done on all participants using a Ryusko autorefractor (Ryusko, Japan GR-3100K, SN 38 AL 2766). The result from the autorefraction was used as the starting point for a full subjective refraction. For children with visual acuity <6/18, cycloplegic refraction was done using cyclopentolate 1% as the dilating agent. One drop instilled into the conjunctival sac every 5 min × 2 doses and allowed for 25–30 min before refraction was done.

Thereafter, all participants had their eyes examined by the ophthalmologist to ascertain the ocular state and cause of reduced vision if any. All the participants underwent a posterior segment examination using direct ophthalmoscopy, with pupillary dilatation where indicated. The retina was examined systematically to identify lesions, including congenital anomalies.

Data analysis

Data were analysed using the Statistical Package for the Social Sciences (SPSS) for Windows (version 20, SPSS inc., Chicago, IL, USA). Descriptive statistics (frequencies, percentages, mean and standard deviation) were used to summarise the variables, while inferential statistics such as odds ratio (OR) and Pearson's Chi-square test were used to test for associations between categorical parameters. The confidence and statistical significance levels were set at 95% and P < 0.05, respectively.

  Results Top

Demographic features

A total of 176 children with special needs were enrolled in the study. The distribution by schools was 51 children (29%) from Hillcrest Special education centre, 11 children (6.3%) from Greenland Special education centre and 114 children (64.7%) from Government Special education school. One hundred and sixty-one children were recruited and evaluated, giving a response rate of 91.5%. Fifteen (8.5%) children were not evaluated for the following reasons: age >17 years,[1] no parental consent,[3] unable to cooperate for evaluation[3] and withdrawal from school for that term.[2] The age range was 5–17 years with the mean age of 12.9 ± 3.3 years and modal age group was ≥13 years (59%). Of the 161 participants, 87 (54%) were male and 74 (46%) were female giving a male-to-female ratio of 1.2:1.

A total of 114 (71%) had single disability and 47 (29.2%) had multiple disabilities. The common category of disability encountered was hearing disability 45 (28%) and developmental disability (DD) 38 (24%). The combinations of the multiple disabilities were 35 (21.9%) with hearing loss–speech disability and DD–speech disability 4 (2.5%). Others were learning disability (LD)–speech disability, physical disability–speech disability, DD–mental disability and hearing loss–physical disability, with 2 (1.2%), respectively.

Vision category

Based on vision category per person, a total of 20 (12.4%) were visually impaired. The distribution of category of vision per person is shown in [Table 1]. [Table 2] shows the frequency of visual impairment (VI) in each type of disability. The frequency of VI was higher in the LD group 4 (28.6%), followed by the DD group 7 (18.4%). A comparison of the frequency of VI among the disability types showed that the children with LD (OR: 3.28 and 95% confidence interval [CI]: 1.73–6.36) and DD (OR: 1.90 and 95% CI: 1.10–3.20), respectively, had significantly higher occurrence of VI. Children with hearing disability had significantly lower occurrence of VI (OR: 0.25 and 95% CI: 0.10–0.53) [Table 3].
Table 1: Category of vision (per person classification)

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Table 2: Frequency of visual impairment in each type of disability

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Table 3: The relationship of visual impairment and disability category

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Causes of visual impairment

The most common cause of VI among the study participants was refractive error in 12 (60%). Others were optic atrophy 2 (10%), cataract 2 (10%), cerebral VI (CVI) 2 (10%), corneal opacity 1 (5%) and aphakia 1 (5%). [Table 4] presents the distribution of the causes of visual by category of vision. Refractive errors and cataract accounted for moderate VI, while severe VI was due to CVI, aphakia and optic atrophy. Blindness was caused by CVI, corneal opacity and optic atrophy.
Table 4: Causes of visual impairment by vision category

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Previous oculo-visual assessment among study participants

One hundred and forty-eight 148 participants responded to the question on previous oculo-visual assessment, only 11 (6.8%) have had their ocular and visual status assessed in the past. Reasons given for not having had a previous eye check were 'the parents or caregivers did not feel the need for an eye check (65.2%)', 'that neither the child's teacher (18.5%) nor the child's doctor (5.9%) had recommended an eye check', 'cannot afford an eye check (2.5%)', 'an eye check will increase the cost of care for my child (4.3%)' and 'my type of child cannot be examined by the eye doctor (1.9%)'.

  Discussion Top

Children with special needs are vulnerable children, prone to social, educational and health neglect.[2],[13] They are entirely dependent on the visual inputs for their personal and educational needs,[14] unfortunately they are at a higher risk of ocular and visual problems than their age matched, apparently normal children.[2],[3],[10],[15]

In this study, most of the participants were of the older school-age group, with a mean age of the 12.9 ± 3.3 years. This was slightly higher than 10.28 ± 3.2 years found among children attending a special school in Enugu, Nigeria but lower than 15.7 ± 3.9 years among deaf children studied in a northern Nigerian special school. However, it is similar to the mean age of 12.1 years found by Gogate et al.[16] in children with learning disabilities attending a special school in India. This high school age may be due to delayed/late enrolment of these children into school, as also reported by Oladejo et al.[13] Repeating classes due to poor academic performance may have also contributed to older mean school age found in this study.

A high prevalence of VI (12.4%) was found in this study. This is comparable to similar studies in Europe that reported high frequencies of VI in children with special needs, ranging from 10.5% to 12.1%.[3],[9],[17],[18] In Nigeria, a comparative study by Adedayo and Samuel[10] found as high as 36.3% of children with Down syndrome (a common cause of DD) compared to 1.3% of the control group were visually impaired. This finding corroborates the reported higher risk of concurrent ocular morbidity resulting in poor visual state in children with special needs. These children should not be left out of VISION 2020: 'THE RIGHT TO SIGHT'. It is their right to be and remain well sighted. Their rights have been well articulated in article 23 of the United Nations Convention on the Rights of the Child, which declares the rights of disabled children to enjoy a full and decent life, in conditions which promote self-reliance and facilitate the child's active participation in the community. It also states the right to special care, education, healthcare, training, rehabilitation, employment preparation and recreation opportunities; all these shall be designed in a manner conducive to the child achieving “the fullest possible social integration and individual development, including his or her cultural and spiritual development.[11]

It is worrisome to have found that the leading causes of the poor visual status in these vulnerable children were largely (at least 70%) avoidable.[10],[18] In accordance to previous similar studies,[3],[7],[14],[16],[19] this study found uncorrected refractive errors as the frequent cause of VI. Onakpoya et al.[20] had noted in their study among special education schoolchildren in Southwest, Nigeria, that the common causes of VI were avoidable, predominantly refractive errors that are easily treatable.

Children with LD and DD were found to have significantly higher occurrence of VI. Some studies[15],[16],[21] have reported an increased risk of VI in children with LD compared to children with other forms of disabilities. One of the most comprehensive population-based studies of children with borderline to profound learning difficulty aged 4–15 years had reported that the prevalence of VI was as much as ten times higher than has been described in general population-based studies.[18] This suggests that specific subtypes of special needs children such as children with learning and/or developmental disabilities may be targeted in eye health awareness campaigns and programme, to improve visual health. This targeted approach may be more cost-effective and efficient, particularly in the resource poor setting.

The frequency of previous oculo-visual assessment among the study participants was significantly low. Only 6.8% of the study participants did have previous oculo-visual assessment. This explains the reason for the high level of unmet visual needs among the study participants. Aghaji et al.[19] in a cross-sectional study of children (5–15 years) with Down syndrome attending a special school in Enugu, Nigeria, found that despite the high prevalence of uncorrected refractive error (76.4%) among these children, none of the children had ever had an ophthalmic assessment nor obtained a refractive correction. This may likely be due to the fact that the caregivers may have been overwhelmed with the other challenges of these children and had no clue to the possibility of a visual problem as the children are often unable to communicate their visual complaints. This highlights the need for an all-inclusive, integrated and comprehensive healthcare service for these children, possibly in their school environment, with appropriate referral for the further evaluation and management where necessary.

  Conclusion Top

There was a remarkably high prevalence of poor visual status but very low frequency of ophthalmic evaluation among children with special needs attending special schools in Calabar, Cross River State, Nigeria.


There is an urgent need for the establishment of a targeted and inclusive school eye healthcare service system, to ensure an early, routine vision screening at the point of enrolment into school by trained ophthalmic team as well as a continuous periodic vision screening by trained school teachers and school health officer for the special needs children. This may be possible through coordinated effort of governments, non-governmental agencies and public-spirited individuals with interest in disabilities issues.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Joshi RS, Somani AA. Ocular disorder in children with mental retardation. Indian J Psychiatry 2013;55:170-2.  Back to cited text no. 1
[PUBMED]  [Full text]  
Woodhouse JM. Investigating and managing the child with special needs. Ophthalmic Physiol Opt 1998;18:147-52.  Back to cited text no. 2
Das M, Spowart K, Crossley S, Dutton GN. Evidence that children with special needs all require visual assessment. Arch Dis Child 2010;95:888-92.  Back to cited text no. 3
Osaiyuwu AB, Ebeigbe JA. Prevalence of visual disorders in deaf children in Benin city. JNOA 2009;15:1-3.  Back to cited text no. 4
Woodhouse JM, Davies N, McAvinchey A, Ryan B. Ocular and visual status among children in special schools in wales: The burden of unrecognised visual impairment. Arch Dis Child 2014;99:500-4.  Back to cited text no. 5
El-Hazmi MA. Early recognition and intervention for prevention of disability and its complications. East Med Health J 1997;3:154-61.  Back to cited text no. 6
Bodack M. Eye and vision assessment of children with special needs in an interdisciplinary school setting. Opt Vis Dev 2011;42:220-6.  Back to cited text no. 7
Taylor D, editor. Normal and Abnormal Visual Development: Paediatric Ophthalmology. Oxford UK: Blackwell Science; 1997. p. 13-28.  Back to cited text no. 8
Salt A, Sargent J. Common visual problems in children with disability. Arch Dis Child 2014;99:1163-8.  Back to cited text no. 9
Adedayo OA, Samuel OW. Ophthalmic manifestations of children with Down's syndrome in Port Harcourt, Nigeria. Clin Ophthalmol 2012:6 1859-64.  Back to cited text no. 10
The United Nations Convention on the Rights of People with Disabilities: A Guide for Disabled People and Disabled People's Organizations; 2002. Available from: http://www.un.org/disabilities/convention/facts.shtml. [Last accessed on 2014 Jan 20].  Back to cited text no. 11
Council for International Organizations of Medical Sciences. International Ethical Guidelines for Biomedical Research Involving Human Subjects. Geneva: 2002: Council for International Organizations of Medical Sciences; 2002. p. 64-70.  Back to cited text no. 12
Oladejo MA, Oladejo SA. Educating students with disabilities in Nigeria: Some challenges and policy implications. Eur J Humanit Soc Sci 2011;3:128-39.  Back to cited text no. 13
Kaur G, Thomas S, Jindal M, Bhatti SM. Visual function and ocular status in children with disabilities in special schools of Northern India. J Clin Diagn Res 2016;10:NC01-4.  Back to cited text no. 14
Tsao WS, Hsieh HP, Chuang YT, Sheu MM. Ophthalmologic abnormalities among students with cognitive impairment in Eastern Taiwan: The special group with undetected visual impairment. J Formos Med Assoc 2017;116:345-50.  Back to cited text no. 15
Gogate P, Soneji FR, Kharat J, Dulera H, Deshpande M, Gilbert C, et al. Ocular disorders in children with learning disabilities in special education schools of Pune, India. Indian J Ophthalmol 2011;59:223-8.  Back to cited text no. 16
[PUBMED]  [Full text]  
Nielsen LS, Skov L, Jensen H. Visual dysfunctions and ocular disorders in children with developmental delay. I. Prevalence, diagnoses and aetiology of visual impairment. Acta Ophthalmol Scand 2007;85:149-56.  Back to cited text no. 17
Surman G, Bonellie S, Chalmers J, Colver A, Dolk H, Hemming K, et al. UKCP: A collaborative network of cerebral palsy registers in the united kingdom. J Public Health (Oxf) 2006;28:148-56.  Back to cited text no. 18
Aghaji AE, Lawrence L, Ezegwui I, Onwasigwe E, Okoye O, Ebigbo P, et al. Unmet visual needs of children with down syndrome in an African population: Implications for visual and cognitive development. Eur J Ophthalmol 2013;23:394-8.  Back to cited text no. 19
Onakpoya OH, Adegbehingbe BO, Omotoye OJ, Adeoye AO. Causes of blindness in a special education school. West Afr J Med 2011;30:47-50.  Back to cited text no. 20
Welinder LG, Baggesen KL. Visual abilities of students with severe developmental delay in special needs education – A vision screening project in Northern Jutland, Denmark. Acta Ophthalmol 2012;90:721-6.  Back to cited text no. 21


  [Table 1], [Table 2], [Table 3], [Table 4]

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