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.
