Astigmatism is due to-

Ans. (d)Ref: Khurana optics 2/e, p. 79; Parsons 22/e, p. 52Most common cause of astigmatism is abnormalities of curvature of cornea. It is usually congenitalLenticular astigmatism is rare, seen in lenticonus (cone shaped lens), congenital tilling, oblique placement, traumatic subluxation of lens