Underlying neurological mechanisms associated with symptomatic convergence insufficiency

Abstract

Convergence insufficiency (CI) is the most common binocular vision problem, associated with blurred/double vision, headaches, and sore eyes that are exacerbated when doing prolonged near work, such as reading. The Convergence Insufficiency Neuro-mechanism Adult Population Study (NCT03593031) investigates the mechanistic neural differences between 50 binocularly normal controls (BNC) and 50 symptomatic CI participants by examining the fast and slow fusional disparity vergence systems. The fast fusional system is preprogrammed and is assessed with convergence peak velocity. The slow fusional system optimizes vergence effort and is assessed by measuring the phoria adaptation magnitude and rate. For the fast fusional system, significant differences are observed between the BNC and CI groups for convergence peak velocity, final position amplitude, and functional imaging activity within the secondary visual cortex, right cuneus, and oculomotor vermis. For the slow fusional system, the phoria adaptation magnitude and rate, and the medial cuneus functional activity, are significantly different between the groups. Significant correlations are observed between vergence peak velocity and right cuneus functional activity (p = 0.002) and the rate of phoria adaptation and medial cuneus functional activity (p = 0.02). These results map the brain-behavior of vergence. Future therapeutic interventions may consider implementing procedures that increase cuneus activity for this debilitating disorder.

Online e-learning during the COVID-19 lockdown in Trinidad and Tobago: prevalence and associated factors with ocular complaints among schoolchildren aged 11–19 years

“…Regarding double vision among digital device users, data on the risk factors are lacking, even though double vision may indicate a more severe problem (convergence insufficiency) ( Alvarez et al, 2021 ) aggravated during intense close work ( Barnhardt et al, 2012 ). Studies have demonstrated a significant association between double vision and both short term (less than 4 h a day ( Nunes et al, 2018 )) and long term (more than 6 h a day ( Comério et al, 2017 )) use of the computer.…”

Short-Term Effect of Spinal Manipulation on the Magnitude of Exophoria in Adults Who Are Asymptomatic: A Randomized Controlled Trial

“…In young adults, base-in prism reading glasses can reduce symptoms associated with exophoria, but do not seem to change near point of convergence or fusional vergence 53 . The high heterogeneity among previous trials in terms of intervention techniques, treatment protocols, and tools used to evaluate binocular vision, warrants further research in the topic 12,13 .…”

“…Currently, common conservative interventions include the use of prism-lensed glasses, alone or combined with oculomotor training. However, evidence about their effectiveness is scant and unclear 12 , and even the most effective approaches are only successful in some cases and require long treatment hours 13 , which may decrease adherence. Thus, there is a need for novel therapeutic protocols and new research on this topic is warranted 12,13 .…”

Peer Review #1 of "Online e-learning during the COVID-19 lockdown in Trinidad and Tobago: prevalence and associated factors with ocular complaints among schoolchildren aged 11–19 years (v0.1)"

“…For females, their hormonal changes may alter the eye's homeostasis, which may cause blurred vision (Gong et al, 2015). Regarding double vision among digital device users, data on the risk factors are lacking, even though double vision may indicate a more severe problem (convergence insufficiency) (Alvarez et al, 2021) aggravated during intense close work (Barnhardt et al, 2012). Studies have demonstrated a significant association between double vision and both short term [less than 4 hrs a day (Nunes et al, 2018)] and long term [more than 6 hrs a day (Comério et al, 2017)] use of the computer.…”