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
Maximum contribution to the refractive power of the eye is by which pa of the eye? 
Select and explain. 
A. Anterior surface of cornea, B. Posterior surface of cornea, C. Anterior surface of lens, D. Posterior surface of lens
A: Anterior surface of cornea
Answer: A: Anterior surface of cornea 
Explanation: Ans: A. Anterior surface of cornea Maximum contribution to refractive power of eye - By anterior surface of cornea.Cornea's anterior surface is approximately spherical with a radius of curvature that is typically 8 mm.This surface is responsible for about two-thirds of the eye's refractive power.