2021 Volume 53 Issue 2 Pages 133-136
Superior oblique palsy causes deviation, diplopia, and abnormal head posture. The Parks-Bielschowsky three-step test is used for diagnosis ; however, we experience cases that do not meet these 3 steps, or whose findings are difficult to evaluate. We were unable to detect findings in cases where deviation and abnormal head posture were mild. As we have to consider differential diagnoses, including systemic disorders causing diplopia, diagnosis is occasionally difficult. Here, we report the usefulness of the change of head tilt with monocular vision in the objective diagnosis of superior oblique palsy associated with diplopia. A 13-year-old Japanese girl experienced diplopia 2 years ago and presented to our hospital with exacerbated diplopia. She showed subtle right exotropic hypertropia and omnidirectional diplopia while her eye movements were preserved in 9 directions. She did not present with ptosis, but complained about circadian changes in diplopia that worsened in the evening. Blood examination, brain magnetic resonance imaging, a nerve conduction test, and a Tensilon test yielded normal results. Diagnosis of Myasthenia gravis, brain tumor, and Fisher syndrome was excluded. While comparing head tilt with the patient's right monocular vision to her left, we identified that head posture with left monocular vision, or the unaffected side was vertical. Alternatively, head posture with the patient's right monocular vision and the affected side revealed a compensating head posture. In this regard, the patient was diagnosed with superior oblique palsy. Diplopia was responsive to ophthalmic surgery. We conclude that the change of head tilt with monocular vision highlights the Bielschowsky sign and can be useful for objective diagnosis.
