This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjunctiva, Subject name: Ophthalmology
[{'content': 'Visual impairment in pterygium is due to - \nSelect and explain. \nA. Astigmatism, B. Myopia, C. Hypermetropia, D. Hazy cornea', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Visual disturbances occur when it encroaches the pupillary area or due to corneal astigmatism induced due to fibrosis in the regressive stage. Occasionally diplopia may occur due to limitation of ocular movements. ref: A K KHURANA OPHTALMOLOGY,E4, Page-81', 'role': 'assistant'}]