Purpose:To describe the clinical presentation,orbital echography(OE)findings,and neuroimaging results of patients with chronic unexplained ocular misalignment,which includes patients with clinically occult thyroid eye disease(TED)that is identifiable through a characteristic OE appearance.Design:Retrospective observational case series.Methods:Seventy eight patients with chronic ocular misalignment suspected of TED because of a history of systemic thyroid disease,proptosis,dysmotility,positive forced ductions,or eyelid retraction or lag were categorized as TED positive,negative,and indeterminate with the use of standardized OE.Demographic,clinical,OE,computed tomography,and magnetic resonance imaging information was collected.Analyses determined the prevalence of TED and differences between TED positive,negative,and indeterminate groups.Results:Fifty-five percent of the findings were suspicious for and most consistent with TED(TED positive);26% of the findings were TED negative,and 19% of the findings were TED indeterminate.Of 30 patients with newly diagnosed TED by OE,70% had no lid retraction,and 20% had no other findings of TED.The inferior rectus followed by the superior rectus/levator complex,medial rectus,and lateral rectus muscles were the most frequently involved muscles.Neuroimaging that was performed in only 26 of 78 patients(33%)did not appear to yield additional diagnostic information.Conclusion:TED is a potential cause of chronic unexplained ocular misalignment in a substantial proportion of patients.These patients frequently present in an occult fashion without other clinical findings that are typical of TED.In these patients,a diagnosis of TED by OE can reduce further costly evaluation.OE appears to have significant clinical usefulness in the diagnosis of TED in patients with unexplained ocular misalignment. Purpose: To describe the clinical presentation, orbital echography (OE) findings, and neuroimaging results of patients with chronic unexplained ocular misalignment, which includes patients with clinically occult thyroid eye disease (TED) that is identifiable through a characteristic OE appearance. Design: Retrospective observational case series. Methods: Seventy eight patients with chronic ocular misalignment suspected of TED because of a history of systemic thyroid disease, proptosis, dysmotility, positive forced ductions, or eyelid retraction or lag were categorized as TED positive, negative, and indeterminate with the use of standardized OE. Demographic, clinical, OE, computed tomography, and magnetic resonance imaging information was collected. Analyses determined the prevalence of TED and differences between TED positive, negative, and indeterminate groups. Results: Fifty-five percent of the findings were suspicious for and most consistent with TED (TED positive); 26% of the findings were TED negative, and 19% Of the findings were TED indeterminate. Of 30 patients with newly diagnosed TED by OE, 70% had no lid retraction, and 20% had no other findings of TED.The inferior rectus followed by the superior rectus / levator complex, medial rectus, and Lateral rectus muscles were the most frequently involved muscles. Neuroimaging that was performed in only 26 of 78 patients (33%) did not appear to yield additional diagnostic information. Conlusion: TED is a potential cause of chronic unexplained ocular misalignment in a substantial proportion of patients. the patients frequently present in an occult fashion without other clinical findings that are typical of TED. these patients, a diagnosis of TED by OE can reduce further costly evaluation. OE can have significant clinical usefulness in the diagnosis of TED in patients with unexplained ocular misalignment