This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitreous and retina, Subject name: Ophthalmology
Macular edema most common cause is - 
Select and explain. 
A. Secondary glaucoma, B. Cataract surgery, C. Retinitis pigmentosa, D. Uveitis
B: Cataract surgery
Answer: B: Cataract surgery 
Explanation: Macular edema occurs when there is abnormal leakage and accumulation of fluid in themacula from damaged blood vessels in the nearby retina. A common cause of macular edema is diabetic retinopathy, a disease that can happen to people with diabetes. Other common cause is, as a complication of cataract surgery. Ref AK khurana 6/e p 280