This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and Errors of Refraction, Subject name: Ophthalmology
Visual acuity of eye is: 
Select and explain. 
A. Refractive power of eye, B. Ability to discriminate two points, C. Ability to increase converging power of eye, D. limitaion of occular movements
B: Ability to discriminate two points
Answer: B: Ability to discriminate two points 
Explanation: Measurement of the threshold of discrimination of two spatially separated targets (a function of the fovea centralis) is termed visual acuity. Refractive power of eye-= +60D(+45D by cornea +15 D by lens). Ability to increase converging power of eye ACCOMODATION limitaion of occular movements - Diplopia