<prompt> Most common cause of unilateral proptosis in adults is -Thyroid ophthalmopathyRhabdomyosarcomaOrbital blow out fractureOrbital cellulitis  <response>: Ans. is a i.e., Thyroid ophthalmopathy The most common cause of unilateral proptosis in children is orbital cellulitis The most common cause of unilateral proptosis in adults is thyroid ophthalmopathy. Most common cause of bilateral proptosis in children - Neuroblastoma me, Leukemia Chloroma Most common cause of bilateral proptosis in adults is thyroid ophthalmopathy. 