What casuse inflamtion and thickening behind the eye?

Inflammation and thickening behind the eye can be caused by several conditions, including thyroid eye disease (Graves' ophthalmopathy), which is associated with hyperthyroidism. Other potential causes include infections, inflammatory diseases like sarcoidosis or multiple sclerosis, and tumors. In some cases, systemic diseases such as autoimmune disorders may also lead to these symptoms. A thorough medical evaluation is necessary to determine the underlying cause.