We have compiled a series of over 300 consecutive clses of unilateral exoph thalmos with definitive diagnosis of the causes of disease process and an adequate follow-up period. Orbital and periorbital tumors constitute 34% of this series, inflammatory diseases including thyroid disorders 50%, arteriovenous abnormalities 4%, and miscellaneous disorders 12%. All patients were thoroughly evaluated clinically and with appropriate diagnostic tests, including ultrasonography (combined A-scan and B-scan), computerized axial tomography (EMI cranial scan), and radiographic tech niques (plain films and...