Human Eye - Defect of Vision and Its Correction

Myopia is also known as near-sightedness. A person with this defect has the far point nearer than infinity. Draw a neat ray diagram to depict image correction for a myopic eye using a suitable lens.

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

Give reasons for the following.
Old people wear spectacles having convex lenses.

A student uses a lens of power $-3.5 \mathrm{D}$. Find the focal length and far point of his eye.

Why the image formed at infinity is often considered most suitable for viewing? Explain

The far point of a myopic eye is _____.

An old age person can read the newspaper by keeping it at $80 \mathrm{cm}$ in front of his eyes. What is the nature and power of lens required to correct the problem?

A person cannot see objects nearer than $75 \mathrm{cm}$ from his eyes while a person with normal vision can see objects up to $25 \mathrm{cm}$ from his eyes. Find the nature, the focal length and the power of the correcting lens used for the defective vision. 

Increase in the converging power of eye lens cause hypermetropia.

What is hypermetropia? What type of lens is used for correcting hypermetropia?

The human eye forms the image of an object at its :

What is the optic nerve of the eye?

Function of optic nerve in human eye:

What happens if ciliary muscles are not working?

What is the first clear part of the eye?

What is the function of cornea in eye?

What job does the pupil of the eye do?

A short sighted person uses a spectacle of power $-0.4 \mathrm{D}$ to see very distant objects. How far can he see without using spectacle?

What is the far point for normal human eyes?

Sheela cannot read newspaper when she holds it closer than $100 \mathrm{cm}.$ The defect in her eye and the power of lens prescribed to her [Normal eye near point $=$ $25 \mathrm{cm}$]