This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Errors of Refraction, Subject name: Ophthalmology
The refractive power of emmatropic eye is 
Select and explain. 
A. 50 D, B. 58D, C. 65 D, D. 68 D
B: 58D
Answer: B: 58D 
Explanation: (58-D) (26-Khurana4rd)* The total dioptric power is +58 D, of which cornea contributes + 43 D and the lens + 15 DDimensions of an adult eyeballAnterior posterior diameter24 mmHorizontal diameter23.5 mmVertical diameter23 mmCircumference75 mmVolume6.5 mlWeight7 gm.