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': "First change in Visual field seen in Glaucoma \nSelect and explain. \nA. Paracentral scotoma, B. Siedel's scotoma, C. Isopter Contraction, D. Arcuate scotoma", 'role': 'user'}, {'content': 'Answer: C \nExplanation: First change in Visual field seen Glaucoma is\xa0Isopter Contraction but is Visually insignigficant.', 'role': 'assistant'}]