This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Lens), Subject name: Ophthalmology
[{'content': 'Which of the following material is used in hard IOL? \nSelect and explain. \nA. PMMA, B. Silicon, C. Hydrogel, D. Acrylic', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., PMMA o Depending on the material of manufacturing, following types of IOLs are thereRigid IOLs Made entirely from polymethyl methacry late (PMMA)Foldable IOLs Are used after phacoemulsification and are made of silicon, acrylic, hydrogel and collamer.Reliable IOLs Ultra thin IOLs and are sued after phokonit technique (micro- incision : 1mm). These are made of hydrogel", 'role': 'assistant'}]