Non-strabismic Binocular Vision Dysfunction among the Medical Students of a Teaching Hospital: A Descriptive Cross-sectional Study

Abstract

Introduction: Non-strabismic binocular vision dysfunctions are visual disorders that affect the person’s binocular vision and visual outcome while performing near tasks and are very common among medical students. This study aimed to find out the prevalence of non-strabismic binocular vision dysfunction among the medical students of a teaching hospital. Methods: A descriptive cross-sectional study was conducted among medical students of a teaching hospital from 25 April 2022 to 25 May 2022. Ethical approval was obtained from the Institutional Review Committee of the same institute (Reference number: 139/17). A detailed ocular evaluation including history, visual acuity, refraction, and detailed orthoptic evaluation was done. Convenience sampling was done. Point estimate and 95% Confidence Interval were calculated. Results: Out of 284 students, 79 (27.81%) (22.60-33.02, 95% Confidence Interval) had non-strabismic binocular vision dysfunctions. Convergence insufficiency was the commonest one seen in 38 (48.10%), followed by divergence excess seen in 8 (10.12%) and convergence excess seen in 8 (10.12%) students. Conclusions: The prevalence of non-strabismic binocular vision dysfunction among medical students was lower than in other studies conducted in similar settings.

Frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university students

“…García-Muñoz [2] Shrestha [3] Franco [4] Darko-Takyi [5] Liu [6] Current showed the prevalence rate of the 18-35-year-old population to be 32.05% [4] and 36.1% [6] , respectively. Meanwhile, the prevalence rate of college students from Spain, Malaysia, Ghana, and Nepal was 13.15% [2] , 40% [12] , 34.3% [5] , and 27.82% [3] , respectively.…”

“…García-Muñoz [2] Shrestha [3] Franco [4] Darko-Takyi [5] Liu [6] Current showed the prevalence rate of the 18-35-year-old population to be 32.05% [4] and 36.1% [6] , respectively. Meanwhile, the prevalence rate of college students from Spain, Malaysia, Ghana, and Nepal was 13.15% [2] , 40% [12] , 34.3% [5] , and 27.82% [3] , respectively. The findings of this study revealed a higher frequency rate of 36.71% among optometric outpatients of Guangxi Medical University, which is similar to the report of Liu et al [6] .…”

“…E lectronic products and close-eye tasks have become increasingly common, leading to a high prevalence of accommodation and non-strabismic binocular vision dysfunction among college students [1][2] . Symptoms of binocular eyestrain, such as red vision, headaches, diplopia, difficulty concentrating, and fatigue, were reported inconsistently in different kinds of literature [2][3][4][5][6] . These symptoms among college students were found to be related to abnormal adjustment function and/or non-strabismic binocular visual function [7] .…”

Binocular Interaction Measurement in Non-Strabismus Patients

“…Refractive disorders, retinal and neurological diseases and ageing can be accompanied by stereovision loss [6][7][8][9]. Non-strabismic accommodative and vergence dysfunctions are common vision anomalies encountered frequently and are usually associated with extensive near work [10,11]. The individual level of binocular cooperation in non-strabismus people depends on many factors, including visual acuity, contrast sensitivity, accommodation, vergence, proprioception, brain activity and so on [3,12,13].…”

Feasibility of measuring fusional vergence amplitudes objectively

“…The evaluation of fusional vergence is fundamental in standard optometric exams, as it provides information about the patient’s binocular vision status and, together with the results of other optometric tests, is useful to diagnose binocular vision dysfunctions [ 6 , 7 ]. The prevalence of non-strabismic binocular vision dysfunctions has been well documented in the literature, although results differ between studies reporting prevalence ranges from 13.5% to 32%; [ 8 – 11 ] 2.29% to 15.81% of these associated with accommodation disorders [ 8 , 10 , 11 ], and 8% to 12.9% related to vergence disorders [ 8 , 12 ]. Convergence insufficiency (CI) and accommodative insufficiency (AI) are the most common non-strabismic binocular dysfunctions with a prevalence ranging from 3.43% to 10.3% for CI [ 8 , 9 , 11 , 13 ] and 11.5% to 5.3% for AI [ 9 , 11 ].…”