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
Which component of the eye has maximum refractive index? 
Select and explain. 
A. Anterior surface of the lens, B. Posterior surface of the lens, C. Centre of the lens, D. Cornea
C: Centre of the lens
Answer: C: Centre of the lens 
Explanation: Refractive index increases from 1.386 in the peripheral coex to 1.41 in the central nucleus of the lens. Because both the curvature and refractive index of the lens increase from the periphery toward the center, each successive layer of fibers has more refractive power. The anterior capsule surface of the lens has a greater refractive index than the posterior capsular surface (1.364-1.381 compared with 1.338-1.357). Ref: Ophthalmology edited by Myron. Yanoff, Jay S. Duker, James J. Augsburger, 2009, Page 383.