Question

9. In case of some people the light coming from distant object gets converged in front of the retina of the eye while light coming from a nearby object converges at retina ofere
a) Name the defect in the eye.
b) what could be the reason for this defect?
c) how could this defect be rectified?​

Answer 1

Answer:

(a) There are three common eye defects, and they are(i) myopia or near-sightedness, (ii) Hypermetropia or far-sightedness, and (iii) Presbyopia.

(b) The defect might be caused by genetics, infection, radiation, or drug exposure, or there might be no known reason. Examples of birth defects include phenylketonuria, sickle cell anemia and Down syndrome.

Answer 2

Answer:

a) Myopia or Short sightedness

b) Eye ball becomes long and cornea becomes curved

c) By using concave lens or negative power lenses

Explanation:

• Myopia or Short sightedness is the defect in eye in which closer objects appear clearly but the distant ones get blurred because the image of the distant object is formed in front of retina.
• In myopia eye ball becomes too long and cornea which is outermost layer of eye becomes curved. so image doesn't get focussed on retina
• Myopia can be corrected by using concave lens or negative power lens. lens converge the rays striking it on retina but by using concave lens which is diverging it diverges the rays outwards on lens and then lens diverge rays coming from longer distance on retina properly.