Objective Assessment of Disparity Vergence after Treatment of Symptomatic Convergence Insufficiency in Children

Abstract

Significance: This first report of the use of objective measures of disparity vergence as outcome measures for symptomatic convergence insufficiency in children provides additional information that is not accessible with clinical tests. The study results also demonstrate that objective measures of vergence could be used in future randomized clinical trials of binocular vision disorders with children.

Purpose: This study was designed to evaluate changes in objective measures of disparity vergence after office-based vergence/accommodative therapy (OBVAT) for convergence insufficiency in children 12 to 17 years old.

Methods: In this prospective trial, we recruited 10 participants with normal binocular vision and 12 with convergence insufficiency. All participants with convergence insufficiency were treated with 12 weeks of OBVAT. The primary outcome measure was average peak velocity for 4° symmetrical convergence steps. Other objective outcome measures of disparity vergence included time to peak velocity, latency, and accuracy. Changes in clinical measures (near point of convergence, positive fusional vergence at near) and symptoms were evaluated.

Results: There was a statistically significant increase in peak velocity and more accurate response amplitude to 4° symmetrical convergence step stimuli after OBVAT compared with baseline measurements. Near point of convergence, positive fusional vergence, and symptoms also statistically significantly improved after OBVAT. Ten of the 12 participants met clinical success criteria.

Conclusions: In this prospective study on the treatment of symptomatic convergence insufficiency in children in which both clinical and objective eye movement measurements were used to evaluate the results of treatment, significant changes were found in symptoms and both clinical and objective measures of disparity vergence after completion of OBVAT in children with symptomatic convergence insufficiency.

Conflict of interest statement

Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest.

Figures

FIGURE 1

Experimental setup of haploscope used to record disparity vergence eye movements.

FIGURE 2

Data analysis of objective eye movements. The plot shows the temporal properties where the position is plotted as a function of time (upper plot) and the velocity is plotted as a function of time (lower plot).

FIGURE 3

Each colored trace is an individual convergence eye movement response to a 4° symmetrical binocular disparity vergence step stimulus from a nonsymptomatic binocularly normal control participant.

FIGURE 4

Each gray line is an individual eye movement response from a 4° symmetrical binocular disparity vergence step stimulus. The blue traces show the average position before office-based vergence/accommodative therapy (OBVAT) for participants 3 (A), 6 (B), and 1 (C). (D, E, F) The same data after OBVAT for participants 3, 6, and 1.

FIGURE 5

Typical convergence insufficiency participant's eye movement responses before and after office-based vergence/accommodative therapy (OBVAT). Position (solid) and velocity (dotted) as a function of time before (blue) and after (red) OBVAT for convergence in far space (upper plot) and convergence in far space (lower plot).

FIGURE 6

(A) The change in peak velocity pre–vision therapy (pre-VT) to post–vision therapy (post-VT) for 4° convergence steps at far. (B) The change in peak velocity pre–vision therapy to post–vision therapy for 4° convergence steps at near.

FIGURE 7

(A) The change in response amplitude pre–vision therapy (pre-VT) to post–vision therapy (post-VT) for 4° convergence steps at far. (B) The change in response amplitude pre–vision therapy to post–vision therapy for 4° convergence steps at near.