This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
[{'content': 'Leaving the capsule behind in cataract surgery is advantageous because it - \nSelect and explain. \nA. Prevents cystoid macular edema, B. Decreases endothelial damage, C. Progressively improves vision, D. Decreased chance of retinal detachement', 'role': 'user'}, {'content': "Answer: A \nExplanation: As postoperative complication following cataract extraction cystoid macular edema(CME) occurs. Cystoid macular edema(CME) refers to collection of fluid in the outer plexiform (Henle's layer) and inner nuclear layer of the retina, centred around the foveola. So leaving the capsule behind in cataract surgery is advantageous prevents cystoid macular edema.", 'role': 'assistant'}]