How is astigmatism corrected?

What is long-sightedness (hypermetropia)?

An old person is unable to see clearly nearby objects as well as distant objects. $(i)$ What defect of vision is he suffering from? $(ii)$ What kind of lens will be required to see clearly the nearby as well as distant objects? Give reasons.

What is the cornea?

Give one cause of long-sightedness (hypermetropia).

Give one example in nature where we can see the dispersion of white light.