ANNALS OF IBADAN POSTGRADUATE MEDICINE
B.A. Olusanya1, M.O. Ugalahi1, O.T. Ogunleye2, and A.M. Baiyeroju1
Background: It is estimated that 19 million children aged below 15 years are visually impaired globally. Twelve million of these are due to uncorrected refractive errors. The aim of this study was to describe the pattern of refractive errors seen in children attending the eye clinic of the University College Hospital, Ibadan, Nigeria.
Methods: A descriptive retrospective study of children with refractive errors seen between January 2011 and December 2012 was conducted. Information on the age, sex, type of refractive error, degree of error (spherical equivalent), presenting complaint, previous spectacle use and return for follow-up visit were retrieved and analyzed using SPSS version 20.
Results: Three hundred and sixty-six children diagnosed with refractive errors accounted for 34.6% of all children seen. Of these, 267 (73%) records were successfully retrieved. The mean age was 10.58 (± 3.14) years, with 156 (58.5%) aged between 11 and 15 years. The male to female ratio was 1:2. The commonest refractive error was myopia, found in 124 (23.2%) of 534 eyes followed by simple myopic astigmatism and compound myopic astigmatism found in 117 (21.9%) and 111 (20.8%) eyes respectively. Majority, 229 (85.8%) had never worn spectacles previously and only 80(30%) children returned for a follow up visit.
Conclusion: Refractive errors constitute a common diagnosis among children seen in our tertiary eye facility. Late presentation and poor follow up among our patients are a cause for concern. Public enlightenment, health education and school eye programs are recommended to reverse this trend.
Keywords: Refractive error, Children, Early detection, Visual impairment, Nigeria.
Dr. M.O. Ugalahi
Department of Ophthalmology,
College of Medicine,
University of Ibadan,
Based on recent figures, it is estimated that 253 million people are visually impaired worldwide, with 36 million people blind while 217 million have low vision.1 Uncorrected refractive error (URE) is the leading cause of visual impairment (VI) globally (43%), followed by cataract (33%).2 URE is responsible for 18% of cases of blindness worldwide, second to cataract (39%). Nineteen million children are estimated to be visually impaired globally, and 12 million of these children have URE.2 In other words, URE is responsible for almost two thirds of cases of visual impairment in children across the world.
Refractive errors include myopia, hypermetropia and astigmatism. They cause defocussing of images formed on the retina of a relaxed eye resulting in poor vision and/or asthenopia (eye strain). Uncorrected refractive errors in children can result in amblyopia, limited or slow academic progress, poor social functioning and impaired quality of life.3-8
Refractive errors can be easily diagnosed, measured and corrected. In fact, spectacle correction of refractive errors is considered to be one of the most cost effective interventions in eye care.3 However, refractive errors often remain uncorrected due to various reasons such as lack of awareness, failure to recognize symptoms in children by parents and teachers, non-availability or inability to afford refractive services and negative attitude to the use of spectacle in children.7
In view of the significant burden of refractive errors in children, this study was conducted to determine the frequency and pattern of refractive errors among children attending the eye clinic at the University College Hospital, Ibadan, Nigeria.
MATERIALS AND METHODS
This was a descriptive retrospective study conducted at the Paediatric Ophthalmology clinic of the University College Hospital Ibadan. Clinical records of children aged 1 to 15 years who were diagnosed with refractive errors between January 2011 and December 2012 were retrieved. Information on age, sex, type of refractive error, degree of error (spherical equivalent), presenting complaint, previous spectacle use and compliance with follow up visit were recorded.
Visual acuity was measured using appropriate methods based on chronological and developmental age. Preverbal children were assessed with the use of behavioral methods, children aged 3 to 5 years were assessed with Lea’s matching test while children older than 5 years were assessed with Snellen’s visual acuity chart. Each child underwent a comprehensive ophthalmic evaluation including; pen torch examination of the anterior segment, assessment of ocular alignment, media clarity, and pupillary response, as well as detailed examination of the anterior segment with a slit lamp microscope and dilated fundoscopy to examine the posterior segment.
All children below the age of 5 years had cycloplegic refraction after instillation of 1% Atropine or Tropicamide or Cyclopentolate eye drops. In addition, children aged 5 years and above who had strabismus, and/or refractive errors greater than 3 diopters also underwent cycloplegic refraction. The rest of the children aged 5 years and above had non-cyloplegic refraction.
Objective refraction was obtained by retinoscopy (using a streak retinoscope). Subjective refraction was subsequently performed for verbal children and appropriate spectacle prescription given as required. Subjective refraction was performed immediately (during the same visit) for children who had non-cycloplegic retinoscopy or 1-2 weeks after cycloplegic retinoscopy. The retinoscopy and refraction was performed by a senior optometrist with over 20 years’ experience in the refraction of children, while spectacle prescriptions were given by a paediatric ophthalmologist. A follow up appointment of three months was scheduled for each patient to assess spectacle adaptation, compliance with spectacle use and corrected visual acuity. Amblyopia therapy was commenced for children who had amblyopia after three months of spectacle wear to allow for spectacle adaptation.
For the purpose of this study, myopia was defined as a spherical error of >-0.5 diopters (D), hyperopia as spherical error of >+0.50D, and astigmatism as a cylindrical error of >0.75D. Anisometropia was defined as a difference of 2.00D or more between the spherical equivalents of both eyes. Amblyopia was defined as a difference in visual acuity of two Snellen lines between the 2 eyes and cycloplegic refraction as refraction done after paralysis of the ciliary muscle with a pharmacologic cycloplegic agent.
Retrieved data was de-identified and kept confidential. The study followed the tenets of the Declaration of Helsinki. Data was analyzed with the Statistical Package for Social Science version 20 (IBM SPSS version 20; IBM). Descriptive and summary statistics were calculated for appropriate variables. For tests of association, p values < 0.05 were considered significant.
A total of 1058 new patients were seen in our paediatric eye clinic during the 24-month study period. Of these, 366 (34.6%) children were diagnosed with refractive error. The clinical records of 267 (73%) of children with refractive errors were successfully retrieved. Females were 177 (66.3%) while males were 90 (33.7%) with a male to female ratio of 1:2. The mean age was 10.58 (± 3.14) years. Majority of the children 156 (58.5%) presented between ages 11 and 15 years. The age and sex distribution of the patients is presented in Figure 1.
The most common presenting complaint was that of poor vision in 191(71%) children. Other presenting complaints included ocular ache, 47(18%) and itching, 16 (6%). Thirteen (5%) children had nonspecific complaints. Previous spectacle use was reported in 38 (14.2%) of the children while only 80(30%) children returned for a follow up visit.
The most common refractive error was myopia which was found in 124 (23.2%) eyes. This was followed by simple myopic astigmatism, 117 (21.9%) eyes and compound myopic astigmatism, 111 (20.8%) eyes. Eighty-eight (16.5%) eyes were found to have hyperopia (Table 1).