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
[{'content': 'You have been referred a middle-aged patient to rule out open angle glaucoma. Which of the following findings will help in the diagnosis: \nSelect and explain. \nA. Cupping of the disc, B. Depth of anterior chamber, C. Visual acuity and refractive error, D. Angle of the anterior chamber', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Appearance of cupping of disc will help for diagnosis. Ref: Textbook of Ophthalmology By Nema, 3rd Edition, Page 175', 'role': 'assistant'}]