This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
YAG laser capsulotomy is used in - 
Select and explain. 
A. Retinal detachment, B. Diabetes, C. After- cataract, D. Refractive errors
C: After- cataract
Answer: C: After- cataract 
Explanation: Posterior capsular opacification (after cataract or secondary cataract) is the most common late complication of uncomplicated cataract surgery. Pattern of opacification: the ring of sommerring and the elschnig pearls Treatment involves the creation of an opening in the posterior capsule, termed a capsulotomy, with the Nd: YAG laser. (photodisruption) Ref: kanski's clinical ophthalmology , 8th edition , page no.293