Post-therapy Functional Magnetic Resonance Imaging in Adults with Symptomatic Convergence Insufficiency.
Optom Vis Sci
; 95(6): 505-514, 2018 06.
Article
in En
| MEDLINE
| ID: mdl-29787484
ABSTRACT
SIGNIFICANCE:
Prior studies have demonstrated the effectiveness of vergence-accommodative therapy in the treatment of convergence insufficiency (CI). These results show the changes in brain activation following therapy through the use of functional magnetic resonance imaging (fMRI).PURPOSE:
The purpose of this study was to investigate changes in brain activation following office-based vergence-accommodative therapy versus placebo therapy for CI using the blood oxygenation level-dependent signal from fMRI.METHODS:
Adults (n = 7, aged 18 to 30 years) with symptomatic CI were randomized to 12 weeks of vergence-accommodative therapy (n = 4) or placebo therapy (n = 3). Vergence eye movements were performed during baseline and outcome fMRI scans.RESULTS:
Before therapy, activation (z score ≥ 2.3) was observed in the occipital lobe and areas of the brain devoted to attention, with the largest areas of activation found in the occipital lobe. After vergence-accommodative therapy, activation in the occipital lobe decreased in spatial extent but increased in the level of activation in the posterior, inferior portion of the occipital lobe. A new area of activation appeared in the regions of the lingual gyrus, which was not seen after placebo therapy. A significant decrease in activation was also observed in areas of the brain devoted to attention after vergence-accommodative therapy and to a lesser extent after placebo therapy.CONCLUSIONS:
Observed activation pre-therapy consistent with top-down processing suggests that convergence requires conscious effort in symptomatic CI. Decreased activation in these areas after vergence-accommodative therapy was associated with improvements in clinical signs such as fusional vergence after vergence-accommodative therapy. The increase in blood oxygen level-dependent response in the occipital areas following vergence-accommodative therapy suggests that disparity processing for both depth and vergence may be enhanced following vergence-accommodative therapy.
Full text:
1
Database:
MEDLINE
Main subject:
Orthoptics
/
Magnetic Resonance Imaging
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Ocular Motility Disorders
/
Convergence, Ocular
/
Occipital Lobe
Type of study:
Clinical_trials
/
Diagnostic_studies
Limits:
Adolescent
/
Adult
/
Female
/
Humans
/
Male
Language:
En
Year:
2018
Type:
Article