This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and refraction, Subject name: Ophthalmology
What is the normal value of Arden index 
Select and explain. 
A. 100-130, B. 130-150, C. 150-180, D. > 185
D: > 185
Answer: D: > 185 
Explanation: Results of EOG are interpreted by finding the Arden ratio (light size ratio) : light peak (LP) Arden ratio =. ______________________________________x100 Minimum height of dark trough(DT) Normal- 185 or above Subnormal - between 185 &165 Abnormal - below 165 Reference : anatomy and physiology , Khurana 3rd edition page no 238