This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy, Development and clinical examination, Subject name: Ophthalmology
The normal value of Arden index is 
Select and explain. 
A. 1, B. 5-Jan, C. Less than 18.5, D. More than 1.85
D: More than 1.85
Answer: D: More than 1.85 
Explanation: Arden ratio = (Maximum height of light peak/Minimum height of dark trough) x 100 Normal curve values are 185 or above. Subnormal curve values are less than 150. Flat curve values are less than 125. Reference : AK KHURANA COMPREHENSIVE OPHTHALMOLOGY, Edition4 , Page-490