What is the other name for the accommodation of the eye?

$A$ person needs a lens of power $-5.5 \, D$ for correcting his distant vision. For correcting his near vision,he needs a lens of power $+1.5 \, D$. What is the focal length (in $cm$) of the lens required for correcting near vision?

Sushil went to an eye specialist for a check-up. The doctor prescribed him to use spectacle lenses of $+0.5 \text{ D}$ power.
$(a)$ Name the defect of vision he is suffering from.
$(b)$ Find the focal length of the spectacle lens.

When one enters a dim-lit room from bright light,one is unable to see the objects in the room for some time. Explain why.

Sometimes you see a person reading the newspaper by placing it very close to his eyes. Which defect is he suffering from? How can the defect be removed?

$(a)$ Explain how a normal human eye is able to see distinctly objects placed at a distance as well as those placed at a nearer distance.
$(b)$ What are the far point and near point of a normal human eye?