Double vision can have a huge impact on the lives of people with thyroid eye disease. Orthoptic evaluation in TED provides data to aid in the diagnosis of restrictive strabismus and for monitoring changes in eye alignment over time, as well as strategies to alleviate symptoms. Once strabismus measurements have been stable (unchanged by more than 5 prism diopters) over a 4–6 month period, more permanent treatment methods for diplopia can be considered (Del Monte MA. Am Orthopt J 52:40–57, 2001). Evaluation of binocular visual function allows for effective management of diplopia symptoms non-surgically and pre- and post- strabismus surgery.