Question

Study the diagram given below and answer the questions that follow:

(i) Name the defect of vision represented in the diagram. Give reason for your answer.
(ii) List two causes of this defect.
(iii) With the help of a diagram show how this defect of vision is corrected.

Answer 1

(i). The defect shown is myopia (nearsightedness). This occurs when the image is formed in front of the retina instead of on it. This happens because:
• The eyeball is elongated.
• The refractive power of the lens is too high (lens is too convex).
(ii). List two causes of this defect.
1. The eyeball becomes too long, increasing the distance between the lens and the retina.
2. Excessive curvature of the cornea or lens increases the focusing power.
(iii) With the help of a diagram, show how this defect of vision is corrected.
Solution: Myopia is corrected using a concave lens, which diverges incoming light rays, moving the focal point back onto the retina.