Which one of the following statements with regard to a short-sighted person is correct?
- (a)A short-sighted person sees the near objects blurred but distant objects clearly and a convex lens is used to correct this defect.
- (b)A short-sighted person sees the near objects clearly but distant objects blurred and a concave lens is used to correct this defect.
- (c)A short-sighted person sees the near objects blurred but distant objects clearly and a concave lens is used to correct this defect.
- (d)A short-sighted person sees the near objects clearly but distant objects blurred and a convex lens is used to correct this defect.
Correct — B, A short-sighted person sees the near objects clearly but distant objects blurred and a concave lens is used to correct this defect. Short sight, or myopia, means the eye converges light too strongly — either the eyeball is too long or the lens too curved — so parallel rays from a distant object meet in front of the retina and the far image blurs. Near objects still focus correctly, which is why reading is comfortable while a road sign is not. A concave lens diverges the incoming rays slightly before they reach the eye, pushing the focus back onto the retina.
- (a)A short-sighted person sees the near objects blurred but distant objects clearly and a convex lens is used to correct this defect. — Both halves are wrong for myopia. Near-blurred with distant-clear describes long sight (hypermetropia), and the convex lens named is the correction for that opposite defect.
- (c)A short-sighted person sees the near objects blurred but distant objects clearly and a concave lens is used to correct this defect. — The lens is right but the symptom is reversed. A concave lens does correct short sight, yet a short-sighted eye sees near objects clearly, not blurred.
- (d)A short-sighted person sees the near objects clearly but distant objects blurred and a convex lens is used to correct this defect. — The symptom is right but the lens is wrong. Adding a convex lens to an eye that already converges too strongly moves the image further in front of the retina and makes distant vision worse.
A normal eye focuses parallel rays exactly on the retina. Myopia moves that focus in front of the retina, so the far point comes closer than infinity and distant objects blur; the remedy is a diverging lens of the right negative power. Hypermetropia does the reverse — the focus falls behind the retina, the near point recedes, and a converging lens is prescribed.
The four options are built from two independent binary choices, symptom and lens, so three of them get one half right. The reliable memory hook is in the name: short sight means sight is good over short distances. From there, an eye that already bends light too much needs a lens that bends it the other way, which is the concave one.
- Myopia is short sight — the image of a distant object forms in front of the retina.
- Its causes are an elongated eyeball or an eye lens of excessive curvature.
- Correction is a concave (diverging) lens of suitable negative power.
- Hypermetropia is long sight, focus behind the retina, corrected by a convex lens.
- Presbyopia is the age-related loss of accommodation, usually needing a converging correction for near work.
Each printed option pairs a symptom with a lens; only one pairing keeps both halves on the same defect.
- Matching the correct symptom to the wrong lens, which is what option (d) offers.
- Assuming short sight means poor vision at short distances.
- Treating presbyopia and hypermetropia as the same defect.
A four-way item built by crossing symptom against lens, so partial knowledge scores zero; the same defect is also asked through its causes, as in the CDS statement-based version.
A person can see near objects clearly through his eyes but cannot see distant objects clearly. The possible reason(s) for this defect could be : 1. Excessive curvature of the eye lens. 2. The eye-ball has become too small. 3. The focal length of the eye lens is too large. 4. Elongation of the eye-ball. Select the correct answer using the code given below :
- (a) 1 only
- (b) 2 and 4 only
- (c) 1 and 4 only
- (d) 1 and 3 only
Answer(c) 1 and 4 only
The same person described in the same words, with the question moved from the remedy to the cause: excessive lens curvature or an elongated eyeball, the two ways an eye can converge light too strongly.
- practice — not a real PYQ
A student can read a book comfortably but cannot read the blackboard from the last bench. The lens prescribed will be
- (a)convex
- (b)concave
- (c)cylindrical
- (d)bifocal
Answer(b) concave — this is myopia, and a diverging lens moves the far focus back onto the retina.
- practice — not a real PYQ
In hypermetropia, the image of a nearby object is formed
- (a)in front of the retina
- (b)on the retina
- (c)behind the retina
- (d)on the blind spot
Answer(c) behind the retina — the eye converges too weakly, so a convex lens is used.