Abstract
Background: Optometrists in Ghana are hampered in performing comprehensive binocular vision assessments, because of the lack of appropriate instruments leading to a paucity of data on vergence disorders and their association with asthenopia among Ghanaian school children.Aim: To establish the prevalence of symptomatic vergence disorders among junior high school (JHS) children in Cape Coast Metropolis, Ghana, in their habitual (vision) states and investigate if there were any associations between these disorders and specific asthenopic symptoms.Methods: A prospective cross-sectional school-based study using a multistage sample of 627 participants aged 12–17 years from JHSs in Cape Coast Metropolis. Participants completed a reliable asthenopic symptoms questionnaire and 220 participants who expressed two or more severe or very severe symptoms were selected for comprehensive binocular vision assessment in their habitual vision state.Results: The prevalence of symptomatic vergence disorders among JHS children in Cape Coast Metropolis was 14.8%. For specific symptomatic vergence disorders, the prevalence was: 1.4% basic esophoria, 1.4% basic exophoria, 8.6% convergence insufficiency, 1.8% convergence excess, 0.8% fusional vergence dysfunctions and 0.8% divergence excess. No participant had symptomatic divergence insufficiency. The study revealed significant associations between some specific symptomatic vergence disorders and specific asthenopic symptoms even though all of these asthenopic symptoms overlapped in other vergence disorders.Conclusion: Presenting complaints of specific asthenopic symptoms does not differentiate between specific types of vergence disorders. A comprehensive binocular vision assessment is vital in the diagnosis and management of these disorders to relieve asthenopia.
Highlights
Studies by Scheiman et al on a clinical paediatric population[1] and Lara et al on a clinic population aged 10–35 years[2] reported that the most common vision disorder after ametropia was binocular vision disorders
This study aimed to establish the prevalence of symptomatic vergence disorders (SVDs) among junior high school (JHS) children in Cape Coast Metropolis, Ghana, and determine whether there were any associations between the asthenopic symptoms and SVDs
The prevalence of SVDs in the JHS students in Cape Coast Metropolis (n = 627) was 14.8%
Summary
Studies by Scheiman et al on a clinical paediatric population[1] and Lara et al on a clinic population aged 10–35 years[2] reported that the most common vision disorder after ametropia was binocular vision disorders. With the increased use of screen-based devices by school children, their near visual demands are increased.[8] One author reports that there is a high prevalence of accommodative and non-strabismic binocular vision disorders in school-going children compared with infants to pre-schoolers.[9] Vergence disorders, such as convergence insufficiency, do become a significant clinical problem most especially when a patient reaches the teenage years.[10] The characteristic asthenopic symptoms – experienced in the habitual state – are exacerbated through increased school work and prolonged periods of reading.[9] Patients most often encountered include high school students, because of the higher demands placed on their near vision system from extended periods of academic work.[10]. Optometrists in Ghana are hampered in performing comprehensive binocular vision assessments, because of the lack of appropriate instruments leading to a paucity of data on vergence disorders and their association with asthenopia among Ghanaian school children
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