Which one among the following is correct for a person suffering from myopia?
- (a)The person can see near objects clearly
- (b)The person can see distant objects clearly
- (c)The person cannot distinguish colours
- (d)The person can neither see near objects nor distant objects clearly
Correct — A, the person can see near objects clearly. In myopia (short-sightedness / near-sightedness) the eye converges light too strongly — usually because the eyeball is too long or the lens too curved — so the image of a DISTANT object forms IN FRONT of the retina and looks blurred. Near objects are still focused correctly on the retina, so a myopic person sees nearby things clearly.
- (b)The person can see distant objects clearly — This is the opposite of myopia. In myopia distant objects are blurred; it is a normal or hypermetropic eye that sees far objects clearly.
- (c)The person cannot distinguish colours — That is colour blindness, a defect of the retina's cone cells — unrelated to myopia, which is a focusing (refractive) error.
- (d)The person can neither see near objects nor distant objects clearly — Myopia affects only distant vision; near vision remains fine, so 'neither near nor distant' is wrong.
Myopia is a refractive defect of vision in which parallel rays from a distant object are brought to a focus in front of the retina. Causes are an elongated eyeball or an over-converging eye lens. The far point (the farthest clearly visible point) moves closer than infinity. It is corrected with a concave (diverging) lens, which spreads the rays slightly before they enter the eye.
'Myopia = my near vision is fine' is a handy memory hook. Distinguish it from hypermetropia (long-sightedness: near objects blurred, corrected by a convex lens) and from colour blindness (a retinal, not refractive, defect). The question rewards knowing exactly which distance a myope sees well: the near one.
- Myopia (short-sightedness): distant objects blurred, near objects seen clearly.
- Cause: eyeball too long or eye lens too converging -> image forms in front of the retina.
- Corrected using a concave (diverging) lens of suitable power.
- Hypermetropia is the opposite (near blurred, convex lens); colour blindness is a separate retinal defect.
- Reversing myopia and hypermetropia (which distance is blurred, and which lens corrects it).
- Confusing a refractive defect (myopia) with colour blindness (a retinal defect).
Asked as 'which defect sees near/far clearly', 'which lens corrects myopia', or a match-defect-to-lens item.
Recently, LASIK (Laser Assisted In-Situ Keratomileusis) procedure is being made popular for vision correction. Which one of the following statements in this context is not correct?
- (a) LASIK procedure is used to correct refractive errors of the eye
- (b) It is a procedure that permanently changes the shapes of the cornea
- (c) It reduces a person's dependence on glasses or contact lenses
- (d) It is a procedure that can be done on the person of any age
Answer(d) It is a procedure that can be done on the person of any age
Same topic — refractive errors of the eye and their correction. Myopia is one such refractive error; LASIK corrects refractive errors by reshaping the cornea, but it cannot be done at any age (the NOT-correct statement).
- practice — not a real PYQ
Myopia (short-sightedness) is corrected by using a
- (a)convex lens
- (b)concave lens
- (c)cylindrical lens
- (d)bifocal lens
Answer(b) concave lens — a diverging lens shifts the image back onto the retina.
- practice — not a real PYQ
A person who can see nearby objects clearly but not distant ones suffers from
- (a)hypermetropia
- (b)myopia
- (c)presbyopia
- (d)astigmatism
Answer(b) myopia — distant vision is blurred, near vision is fine.