This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Elementary Optics, Subject name: Ophthalmology
Maximum contribution to the refractive power of the eye is by: 
Select and explain. 
A. Anterior surface of cornea, B. Anterior surface of lens, C. Posterior surface of cornea, D. Posterior surface of lens
A: Anterior surface of cornea
Answer: A: Anterior surface of cornea 
Explanation: Ans. (a) Anterior surface of corneaRef: Cornea by Mannis p. 145On average anterior cornea has refractive power of +48D of convergence and posterior cornea -5D of divergence.