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
Pinhole can reduce refractive error up to - 
Select and explain. 
A. 3 D, B. 1 D, C. 5 D, D. 10 D
A: 3 D
Answer: A: 3 D 
Explanation: Pin-hole test: It helps in confirming whether the optical correction in the trial frame is correct or not.
An improvement in visual acuity while looking through a pinhole indicates that optical correction in the trial frame is incorrect.
PPinholecan reduce refractive error upto 3 D.