Post-therapy Functional Magnetic Resonance Imaging in Adults with Symptomatic Convergence Insufficiency

Area of Science:

• Neuroscience
• Ophthalmology
• Vision Science

Background:

• Convergence insufficiency (CI) is a common binocular vision disorder.
• Vergence-accommodative therapy (VAT) has shown promise in treating CI.
• Functional magnetic resonance imaging (fMRI) can reveal brain changes associated with therapeutic interventions.

Purpose of the Study:

• To investigate brain activation changes following VAT compared to placebo therapy in adults with symptomatic CI.
• To utilize blood oxygenation level-dependent (BOLD) fMRI signals to assess these changes.

Main Methods:

• Seven adults with symptomatic CI were randomized into two groups: VAT (n=4) and placebo therapy (n=3).
• Participants underwent 12 weeks of therapy.
• fMRI scans were conducted at baseline and post-therapy to measure brain activity during vergence eye movements.

Main Results:

• Pre-therapy fMRI showed significant activation in the occipital lobe and attention networks.
• VAT led to decreased spatial extent but increased intensity of activation in the occipital lobe, with new activation in the lingual gyrus.
• Both VAT and placebo therapy reduced activation in attention areas, but the effect was more pronounced with VAT.

Conclusions:

• Pre-therapy brain activation patterns in CI suggest conscious effort is required for convergence.
• Reduced activation in attention areas post-VAT correlates with improved clinical measures of vergence.
• Enhanced BOLD response in occipital areas after VAT indicates improved disparity and vergence processing.