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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Visual impairment in pterygium is due to -
assistant
The correct answer is  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