Abstract
Purpose: :
This study sought to investigate whether the transient preprogrammed component of symmetrical convergence was correlated to functional activity within the brain studying healthy controls and patients with convergence insufficiency (CI) before and after vergence training.
Methods: :
Eye movements and fMRI data from four CI patients before and after vergence training were compared to seven binocularly normal controls. A hierarchical independent component analysis (ICA) was conducted on the blood oxygenation level dependent (BOLD) fMRI data stimulated using a block design of sustained fixation compared to symmetrical vergence step eye movements.
Results: :
The correlation between the ICA reference vector and the experimental design improved after training for CI patients. The magnitude of the preprogrammed component of vergence movements was reduced in CI patients prior to training compared to controls and improved after training. The magnitude of the preprogrammed component was significantly correlated to the ICA reference vector from the midbrain (r = 0.78, p<0.001).
Conclusions: :
The magnitude of the preprogrammed component in vergence is significantly correlated to functional activity within the midbrain. Data support that vergence training improves functional activity within the midbrain and the magnitude of the preprogrammed component within vergence responses for CI patients.
Keywords: vergence • ocular motor control • image processing