What is Astigmatism is due to- and explain in detail?
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