The change in focal length of an eye lens is caused by the action of the

How does an eye manage to see objects in dim light and bright light?

What is the other name of near-sightedness?

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

$(a)$ State two main causes of a person developing near-sightedness (myopia). With the help of a ray diagram, suggest how this disability can be corrected.
$(b)$ The far point of a myopic person is $150 \ cm$ in front of the eye. Calculate the focal length and power of the lens required to enable him to see distant objects clearly.

Sometimes you see a person reading the newspaper by placing it far away from their eyes. Which defect is the person suffering from? How can this defect be corrected?