This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Ophthalmology
"Iris bombe" occurs due to 
Select and explain. 
A. Adherent Glaucoma, B. Anterior Synechiae, C. Posterior Synechiae, D. Ring synechiae
D: Ring synechiae
Answer: D: Ring synechiae 
Explanation: Posterior synechiae extending for 360 degrees around the pupil (seclusio pupillae), prevent the passage of aqueous from the posterior to the anterior chamber. This gives rise to forward bowing of the peripheral iris causing an 'iris bombe'. This may lead to elevation of IOP due to secondary angle closure by the peripheral iris.