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Eye deviation in patients with one-and-a-half syndrome
K Johkura1, A Komiyama, Y Kuroiwa
1Department of Neurology, Medical Center, Yokohama City University, Yokohama, Japan. kjm0502@urahp.yokohama-cu.ac.jp
European Neurology
|November 30, 2000
Summary
Patients with one-and-a-half syndrome exhibit outward eye deviation when fixation is prevented. Eye movements during fixation suggest specific neural pathway involvement, aiding diagnosis.
Area of Science:
- Neuroscience
- Ophthalmology
Background:
- One-and-a-half syndrome is a rare neurological disorder characterized by conjugate horizontal gaze palsy and ipsilateral internuclear ophthalmoplegia.
- Understanding the precise malalignments of visual axes is crucial for diagnosing and managing this complex condition.
Observation:
- Eye positions were measured in 4 patients with one-and-a-half syndrome under conditions with and without Frenzel goggles to prevent fixation.
- With Frenzel goggles, all patients displayed mild outward deviation (exotropia) in both eyes.
- Upon removal of Frenzel goggles, patients showed ipsilateral adduction for fixation and contralateral exotropia in the acute stage, or bilateral adduction to midposition in the convalescent stage.
Findings:
- Divergent eye positions were observed when fixation was prevented in one-and-a-half syndrome.
- Greater ipsilateral outward deviation correlated with a transition to ipsilateral internuclear ophthalmoplegia.
- Greater contralateral outward deviation correlated with a transition to ipsilateral gaze palsy.
Implications:
- Findings suggest divergent eye positions when fixation is prevented in one-and-a-half syndrome.
- Ipsilateral eye deviation may indicate medial longitudinal fasciculus involvement.
- Contralateral eye deviation may indicate paramedian pontine reticular formation involvement, with fixation potentially inducing secondary deviations or adaptations.