<prompt> Progressive pterygium causes:MyopiaHypermetropiaAstigmatismCataract  <response>: 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 keratectomylamellar keratoplasty 