Myopia is a defect in human vision where an image of a
- (a)nearby object is focused beyond the retina.
- (b)nearby object is focused before the retina.
- (c)distant object is focused before the retina.
- (d)distant object is focused beyond the retina.
Correct — C, a distant object is focused before the retina. Myopia (short-sightedness) is the eye defect in which the eyeball is too long or the eye lens too strongly converging, so light from a distant object is brought to a focus in front of the retina instead of on it. The image that reaches the retina is therefore blurred, which is why a myopic person cannot see distant objects clearly. It is corrected with a concave (diverging) lens.
- (a)nearby object is focused beyond the retina. — of a nearby object does not describe the defect.
- (b)nearby object is focused before the retina. — Near objects are seen clearly in myopia, so a nearby object focused before the retina mis-states the defect.
- (d)distant object is focused beyond the retina. — A distant object focused beyond (behind) the retina describes hypermetropia (long-sightedness), the opposite defect, not myopia.
In a normal eye the cornea-lens system focuses parallel rays from distant objects exactly on the retina. of a far object forms in front of the retina — usually because the eyeball is elongated or the converging power of the eye is too high. The far point moves closer than infinity, so distant objects blur while near objects stay sharp.
Two clues fix the answer: myopia troubles distant vision (so the object must be distant, ruling out the 'nearby' options) and the image forms short of the retina (before it, ruling out 'beyond'). Only a distant object focused before the retina satisfies both.
- Myopia (short-sightedness): distant objects appear blurred, near objects are seen clearly.
- The image of a distant object forms in front of (before) the retina.
- Common causes are an elongated eyeball or an eye lens that is too converging.
- It is corrected using a concave (diverging) lens of suitable power.
In myopia the distant-object image forms before the retina — so the answer is (c).
- Swapping myopia and hypermetropia — myopia gives an image before the retina (concave lens); hypermetropia behind the retina (convex lens).
- Reading 'nearby object' — in myopia it is the distant object whose image is misplaced.
Asked as identifying where the image forms in a named eye defect — match myopia to a distant object focused in front of the retina.
No directly related past PYQ was found.
- practice — not a real PYQ
Myopia (short-sightedness) is corrected using a
- (a)convex lens
- (b)concave lens
- (c)cylindrical lens
- (d)bifocal lens
Answer(b) concave lens — it diverges the rays so the image falls on the retina.
- practice — not a real PYQ
In hypermetropia, the image of a nearby object is focused
- (a)on the retina
- (b)before the retina
- (c)behind the retina
- (d)at the cornea
Answer(c) behind the retina — the opposite of myopia, corrected with a convex lens.