This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Uveal tract, Subject name: Ophthalmology
[{'content': 'Iris bombe is due to - \nSelect and explain. \nA. Segmental posterior synechiae, B. Total posterior synechiae, C. Ring synechiae, D. Anterior synechiae', 'role': 'user'}, {'content': "Answer: C \nExplanation: Annular posterior synechiae (ring synechiae) are 360o adhesions of pupillary margin to anterior capsule of lens. These prevent the circulation of aqueous humour from posterior chamber to anterior chamber (seclusio pupillae). Thus, the aqueous collects behind the iris and pushes it anteriorly (leading to 'iris-bombe' formation)", 'role': 'assistant'}]