What is the far point and near point of the human eye with normal vision?

$A$ student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?

What is meant by the power of accommodation of the eye?

Why does the Sun appear reddish early in the morning?

The human eye can focus on objects at different distances by adjusting the focal length of the eye lens. This is due to

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