This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Refractive power of eye can be changed by: 
Select and explain. 
A. Radial keratotomy, B. Keratomileusis, C. IOL, D. All
D: All
Answer: D: All 
Explanation: A i.e. Radial keratotomy; B i.e Keratomileusis; C i.e. IOL