This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cornea and sclera, Subject name: Ophthalmology
Most impoant factor in the convergence of light rays on the retina is 
Select and explain. 
A. Length of eye ball, B. Dioptre power of lens, C. Centre of lens, D. Cornea
D: Cornea
Answer: D: Cornea 
Explanation: The total dioptric power of the eye is about +60 D out of which about +44 D is contributed by the cornea and +16 D by the crystalline lens. The human eye is spherical and its internal pas are transparent so that the maximum amount of light can reach the retina. The cornea surrounds and protects the eye. It is made of transparent gel-like material that helps converge light rays onto the retina. Khurana 4e pg: 26