Question

Given diagram is showing a defect of a human eye. Study it and answer the following question.
Give the reason for this defect of the eye in the human being.

Answer 1

- Hint: In this, first we should know that As Lens here is very thin which is known as a convex lens. So, this lens is used when a person is not able to see nearby objects clearly and can see far objects very clearly. So, this is the case of Hypermetropia.

Complete step-by-step solution -
Hypermetropia is also known as long sightedness. In this, people can see far objects very clearly and cannot be able to see near objects clearly. In this case, the object image is formed behind the retina. It is caused when the eyeball is too short or the focal length is too long. For example: An old person cannot see newspaper letters clearly due to this disease.

In this, the image of the nearby object is formed behind the retina. This means that light is focus too far back on the eye due to which things appear to be blurred. Thus, Long sightedness is corrected using a convex lens. It is placed in front of the eye moving the image forward and focusing it correctly on the retina.

Note: Be careful by the word myopia and hypermetropia because both are the terms related to eye defects. Myopia means people who cannot see far objects clearly and hypermetropia means people who cannot see near objects clearly. So, to correct myopia, a concave lens is used whereas a convex lens is used in hypermetropia.

This is an image of myopia. So, don't get confused by both defects.