Asymmetric proptosis in thyroid eye disease.

Area of Science:

• Ophthalmology
• Endocrinology

Background:

• Thyroid eye disease (TED) can manifest with asymmetry in orbital presentation.
• Understanding the prevalence and associations of asymmetric TED is crucial for diagnosis and management.

Purpose of the Study:

• To determine the prevalence of asymmetric TED in an Australian cohort.
• To investigate clinical, biochemical, and radiological factors associated with asymmetric TED.

Main Methods:

• Retrospective analysis of 86 patients with TED, utilizing Hertel exophthalmometry and orbital CT scans.
• Asymmetry defined as ≥3 mm difference in globe protrusion.
• Extraocular muscle volumes quantified via CT scan segmentation.

Main Results:

• 33% of patients exhibited asymmetric TED.
• No significant differences in demographics, thyroid status, or disease activity between asymmetric and non-asymmetric groups.
• Significantly greater extraocular muscle volumes were found in the asymmetric orbit.

Conclusions:

• Asymmetric TED is common and associated with increased extraocular muscle volumes.
• Muscle enlargement is a potential contributor to asymmetric proptosis in TED.
• TED should be considered in the differential diagnosis of asymmetric orbital inflammatory conditions.