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Imaging of Convergence Insufficiency Treatment Effects (ICITE) Pilot Study: Design and Methods
Vision Development & Rehabilitation (2017)
  • Tamara S. Oechslin
  • Nicklaus F. Fogt
  • Nasser H. Kashou, Wright State University - Main Campus
  • Andrew J. Toole
  • Chirag B. Limbachia
  • Douglas E. Widmer
  • Marjean T. Kulp
Background: The blood-oxygen-level-dependent
(BOLD) signal from functional magnetic
resonance imaging (fMRI) identifies brain
activation during specific tasks.1,2 This paper
describes the design and methodology of
the Imaging of Convergence Insufficiency
Treatment Effects (ICITE) Study, a two-phase
study comparing BOLD activations during
vergence eye movements in symptomatic
convergence insufficiency (CI) subjects (1) to
those with normal binocular vision (NBV) and
(2) after office-based vergence/accommodative
therapy (OBVAT) versus office-based placebo
therapy (OBPT).
Methods: Young adults, 18 to 30 years, with
NBV or symptomatic CI (near exophoria at least
4Δ [prism diopters] greater than at distance,
receded near point of convergence [NPC],
and insufficient positive fusional vergence
[PFV]) were enrolled. During fMRI scanning,
subjects were instructed to fuse a random-dot
stereogram stimulus with vergence demands
ranging from -3Δ to +25Δ. CI subjects were
then randomized to 12 weeks of OBVAT or
OBPT. Vision and fMRI examination at outcome
were performed by a masked examiner. BOLD
signal at baseline was compared between NBV
and CI patients. Later, the BOLD response at
baseline was compared to that following vision
therapy for those with CI.
Conclusion: The imaging results are expected
to advance understanding of neurological
mechanisms of CI and the effects of therapy
on the vergence system, which in turn may
guide development of future research that
could lead to new treatment strategies.
  • convergence insufficiency,
  • functional magnetic resonance imaging,
  • eye movements
Publication Date
December, 2017
Citation Information
Oechslin TS, Fogt NF, Kashou NH, Toole AJ, Limbachia CB, Widmer DE, Kulp MT. Imaging of convergence insufficiency treatment effects (ICITE) pilot study: Design and methods. Vision Dev & Rehab 2017;3(4):207-15.