Astigmatism is due to-: (A) Irregularity of curvature of cornea, (B) Irregularity of curvature of lens, (C) Forward displacement of the lens, (D) Irregularity of curvature of cornea > Irregularity of curvature of lens
Answer is D. 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