Vergence findings and horizontal vergence dysfunction among first year university students in Benin City, Nigeria

PURPOSE: The study was designed to determine the prevalence of vergence dysfunctions among first year university students in Nigeria and to document the measures that define the vergence system of the visual system. METHODS: A cross-sectional study of first year students of the University of Benin, Benin City, Nigeria, who presented for the mandatory eye examination as part of their medical examinations required for clearance was conducted. A battery of tests that defines the vergence system including near and far phoria, positive and negative fusional vergence amplitudes at far and near, near point of convergence (NPC) and AC/A ratio were measured using conventional clinical protocols. RESULTS: The prevalence of vergence dysfunction among 212 first year university students who satisfied the inclusion criteria and gave consent to participate was 12.7%, with convergence insufficiency being the most common vergence dysfunction. Blurred vision, headache and diplopia were the most frequently reported visual symptoms. CONCLUSION: There is a considerable prevalence of previously undiagnosed vergence dysfunctions in this population of students. The study underscored the need to carry out a thorough binocular vision assessment as part of the battery of tests administered to newly admitted students in this community to forestall any adverse effect the presence of vergence dysfunctions might have on the academic activity of university students.