Purpose: To report the prevalence and the degree of significant asymmetric orbital involvement secondary to thyroid-related (Graves) orbitopathy in a large patient population.
Methods: The prevalence of exophthalmometric differences of > or =2 mm was determined in 391 consecutive patients diagnosed with Graves orbitopathy from the Jules Stein Eye Institute Division of Ophthalmic Plastic and Reconstructive Surgery patient registry.
Results: Thirty-six of 391 patients (9%) in this cohort had asymmetric proptosis with a difference of > or =2 mm, based on single-observer Hertel measurements before orbital decompression surgery. This finding was similar among men (11/95, 12%) and women (25/296, 8%) but was not statistically significant (P= 0.358; 95% CI, 0.6% to 7.8%). Also, we found no racial variations in the incidence of unilateral disease.
Conclusions: Clinically, unilateral or asymmetric Graves orbitopathy is common and can lead to misdiagnosis or to unnecessary testing. Thyroid-related orbitopathy must be considered in the differential diagnosis for any case of asymmetric exophthalmos.