This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjuctiva, Subject name: Ophthalmology
[{'content': 'Progressive pterygium causes: \nSelect and explain. \nA. Myopia, B. Hypermetropia, C. Astigmatism, D. Cataract', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans: c (Astigmatism) Ref: AK Khurana, 4th ed, p. 81Corneal astigmatism may occur in pterygium due to fibrosis in regressive stage.Pterygium:* Wing shaped fold of conjunctiva encroaching cornea from either side within the palpebral fissure* Degeneration & hyperplastic condition of conjunctiva* May be unilateral or bilateral, usually starts nasally (triangular fold of conjunctiva)* Symptoms-usually asymptomatic- Visual disturbance due to corneal astigmatism]- Diplopia* Psuedopterygium- Due to chemical bums* Treatment-Surgical excisionRecurrent recalcitrant pterygium - Surgical excision + lamellar keratectomy+lamellar keratoplasty', 'role': 'assistant'}]