What is the muscular structure located behind the cornea in our eye called?

What is long-sightedness (hypermetropia)?

The far point of a myopic person is $150 \ cm$ in front of the eye. Calculate the focal length and the power of a lens required to enable him to see distant objects clearly.

In the eye of a person suffering from myopia (nearsightedness),where is the image of a distant object formed?

What is the least distance of distinct vision of a normal human eye (in $cm$)?

$A$ person needs a lens of power $-2.5 \ D$ for correcting his vision. Name the defect of vision he is suffering from. Which lens will he be using for the correction? Also,find the focal length of the lens.