Clinical Profile of Patients with Vergence Dysfunction at the University College Hospital, Ibadan

Paediatric Ophthamology & Strabismus

Abstract

Introduction: Fusional vergences are optomotor  reflexes designed to maintain the alignment of the eyes so that similar retinal  images are projected onto corresponding areas, a requirement for binocular single vision1 . Vergence dysfunction describes conditions  that disrupt normal fusional vergence. Convergence insufficiency (CI) is the inability to maintain convergence on objects as  they approach the eyes from distance to near.2 There is variability in the reported prevalence of CI, ranging from 1.75 to 33% with an  average of 5%3 . There is no known ethnic or racial predilection. Anecdotal evidence suggests that tests of vergence dysfunction are  not routinely performed in many ophthalmic practices in our environment. The aim of this study was to describe the clinical profile of  patients diagnosed with CI and Fusional Dysfunction (FD) in the Pediatric Ophthalmology and Strabismus clinic of University College  Hospital Ibadan, since the screening for vergence dysfunction became routine in the clinic.

Methods: This was a retrospective review of case notes of patients diagnosed with convergence insufficiency and fusional vergence  dysfunction between April 2015 and June 2017. The diagnostic criteria used for convergence insufficiency were exodeviation at near or  > 4 prism diopter( difference between distance and near, remote near point of convergence (NPC) of 6cm or higher, reduced  convergence amplitudes (less than 35 base out), and history of difficulty with near tasks.2,4,5 While the diagnostic criterion for  fusional dysfunction was reduced fusional convergence amplitude irrespective of the patient’s NPC.