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': "Earliest visual field change in open angle glaucoma is – \nSelect and explain. \nA. Paracentral scotoma, B. Ring scotoma, C. Siedel's scotoma, D. Arcuate scotoma", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Earliest clinically significant field defect is small wing-shaped paracentral scotoma.', 'role': 'assistant'}]