for a normal eye the cornea of eye provides a converging power of 40D and the least converging power of eye lens behind the cornea is 20D. using the information , the distance between the retina and the cornea-eye lens can be estimated to be -

Q. For a normal eye, the far point is at infinity and the near point of distinct vision is about $25cm$ in front of the eye. The cornea of the eye provides a converging power of about $40$ dioptres, and the least converging power of the eye - lens behind the cornea is about $20$ dioptres. From this rough data estimate the range of accommodation (i.e., the range of converging power of the eye-lens) of a normal eye.