Write the value of the near point of distinct vision for a normal eye.

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

What is long-sightedness (hypermetropia)? List two causes for the development of long-sightedness. Describe with a ray diagram how this defect may be corrected by using spectacles.

How are we able to see nearby and also the distant objects clearly?

$A$ 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.

$A$ person suffering from an eye defect uses lenses of power $-1\, D$. Name the defect he is suffering from and the nature of lens used.