Which of the following is NOT true regarding Thyroid Eye Disease?

• A. It is often worse at the end of the day
• B. It can cause unilateral disc edema
• C. It is associated with proptosis and upper eyelid retraction
• D. The inferior rectus and medial rectus are usually affected first

Answer: (A)

Thyroid eye disease is an autoimmune inflammatory process in the orbit that enlarges extraocular muscles and orbital tissues, leading to proptosis, eyelid retraction, and restrictor-type eye movements that cause diplopia. A key feature is that the inferior rectus is most often affected first, followed by the medial rectus, which explains why patients commonly develop vertical diplopia and specific movement limitations early in the disease course. The optic nerve can be involved if the crowding becomes severe, producing optic neuropathy that may present as disc edema; this can be unilateral in some cases. Importantly, there isn’t a consistent diurnal pattern in TED where symptoms are specifically worse at the end of the day. The disease activity and manifestations are more tied to inflammatory activity and thyroid control rather than a predictable time-of-day fluctuation.