Background and purpose: To conduct a retrospective study to investigate the causes of acquired superior oblique dysfunction, excluding paralysis, in a consecutive series of adult patients and to compare presenting symptoms and clinical findings.
Methods: A retrospective review of all adult patients with superior oblique dysfunction between the ages of 18 and 80 who met the study profile was conducted at Saint Louis University Medical Center between January 2000 and April 2012. The presenting symptoms, clinical findings, and treatment course for each patient was recorded. The study was approved by the Institutional Review Board of our institution.
Results: Acquired forms of nonparalytic superior oblique dysfunction were identified in forty-eight patients. These included superior oblique myokymia (twenty-three patients), superior oblique click syndrome or variable Brown syndrome (nine), canine tooth syndrome (five), spontaneous acquired Brown syndrome (four), iatrogenic or traumatic Brown syndrome (four), and ocular neuromyotonia affecting the superior oblique (three).
Conclusions: Several nonparalytic entities were identified that caused superior oblique dysfunction. Clinical findings may be similar despite entirely different mechanisms. Subjective symptoms may be difficult for the patient to describe or for the examiner to elicit on the day of the examination. Specific techniques can be used in eliciting, differentiating, and documenting the conditions. These included trochlear palpation, modified head tilt technique, interpretation of torsion, and Hess charts.
Keywords: Brown syndrome; canine tooth syndrome; ocular neuromyotonia; superior oblique; superior oblique click syndrome; superior oblique myokymia.
© 2014 Board of regents of the University of Wisconsin System, American Orthoptic Journal, Volume 64, 2014, ISSN 0065-955X, E-ISSN 1553-4448.