Purpose: To determine the extent of superior oblique enlargement in thyroid eye disease (TED) by comparing the cross-sectional superior oblique areas of TED patients with those of unaffected control subjects.
Methods: The medical records of TED patients treated for strabismus from January 2005 to January 2016 were reviewed retrospectively for demographic and surgical data. The cross-sectional superior oblique area was compared to age-matched controls on high-resolution orbital computed tomography (CT) using a standardized protocol.
Results: A total of 46 TED patients and 18 controls were included. The mean superior oblique cross-sectional area in TED subjects was 250% larger than in controls (22.88 ± 6.64 mm2 vs 9.32 ± 1.85 mm2. The mean cross-sectional area was >3 standard deviations from the mean of the control group in 96% of TED patients.
Conclusions: Superior oblique enlargement in TED may occur more frequently than generally recognized, challenging the notion that TED is primarily a disease of the rectus muscles.
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