This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Open angle glaucoma causes – 
Select and explain. 
A. Sudden loss of vision, B. Difficulty in dark adaptation, C. Amaurosis fugax, D. Uniocular diplopia
B: Difficulty in dark adaptation
Answer: B: Difficulty in dark adaptation 
Explanation: Some patients experience difficulty in dark adaptation.