What is the most common cause of exophthalmos in adults?

The most common cause of exophthalmos in adults is thyroid eye disease, also known as Graves' ophthalmopathy. This condition is associated with hyperthyroidism, particularly in patients with Graves' disease, where an autoimmune process results in the inflammation and swelling of the eye muscles and tissues behind the eyes. This inflammation leads to the characteristic forward displacement of the eyeball, known as exophthalmos.

In thyroid eye disease, the increased deposition of glycosaminoglycans (GAGs) and inflammation contributes to the enlargement of the extraocular muscles and the retro-orbital fat, pushing the eyeball forward. Symptoms often accompany exophthalmos, such as ocular discomfort, diplopia, and visual impairment, making this condition significant in ophthalmology practice.

Other options such as trauma may cause immediate ocular changes but are not as prevalent as thyroid eye disease in causing exophthalmos. Similarly, while diabetes can lead to various ocular complications, it is not a leading cause of exophthalmos in adults. Allergies can cause ocular symptoms but typically do not result in exophthalmos, focusing instead on conjunctival inflammation or swelling. Thus, thyroid eye disease stands out as the most common underlying cause for this condition in the