Question

Sita has difficulty to read the newspaper. Her defect of vision can be corrected by using spectacles containSita has difficulty to read the newspaper. Her defect of vision can be corrected by using spectacles contain

Answer 1

Sita has difficulty to read the newspaper. Her defect of vision can be corrected by using spectacles containing convex lens.

Explanation:

The defect of vision suffered by Sita is Hypermetropia.

The three defects of vision are =>

1. Myopia

Person cannot see distant objects clearly.

Person can see nearby objects clearly.

Correction can be done by Concave Lens.

Myopia is also known as near-sightedness and this defect can occur due to two reasons either by excessive curvature of the eye lens or by elongation of the eyeball.

2. Hypermetropia

Person can see distant objects clearly.

Person cannot see nearby objects clearly.

Correction can be done by Convex Lens.

Hypermetropia is also known as far-sightedness and this defect can occur due to two reasons either the focal length of the eye lens is too long or the eyeball has become too small.

3. Presbyopia

This defect of vision happens due to ageing. For both nearby and distant objects it becomes hard for person to see it clearly.

Correction can be done by bi-focal lenses which have both convex and concave lens.

Presbyopia can occur due to two reasons gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens.