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Question
The picture given here shows a person wearing 'half-moon' spectacles. What sort of eye-defect do do you think he has? Why are these particular spectacles useful to him?
Solution
As the person is wearing half-moon spectacles, he should be suffering from the eye defect called long-sightedness, or hypermetropia, because his spectacles are fitted with convex lens. The convex lenses form the images of nearby objects at the near point of his eye, and he can, therefore, see these objects clearly.
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RELATED QUESTIONS
Millions of people in the developing countries of the world are suffering from corneal blindness. These persons can be cured by replacing the defective cornea with the cornea of a donated eye. A charitable society of your city has organised a campaign in your neighbourhood in order to create awareness about this fact. If you are asked to participate in this mission, how would you contribute in this noble cause?
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The kind of lens required to correct Myopia
Name the body part with which the terms myopia and hypermetropia are connected.
Your friend can read a book perfectly well but cannot read the writing on blackboard unless she sits on the front row in class.
Is she short-sighted or long-sighted?
The near point of a long-sighted person is 50 cm from the eye.
(a) Can she see clearly an object at:
(i) a distance of 20 cm?
(ii) at infinity?
A person can read a book clearly only if he holds it at an arm's length from him. Name the defect of vision:
if the person is an old man
Study the following diagram carefully and then answer the questions that follow. The diagram is depicting a defect of the human eye :
(i) Identify the defect shown in the diagram.
(ii) Give two possible reasons for the above defect.
Choose the Odd One Out:
Due to elongation of _______ and increase in curvature of the eye lens, a person cannot see distant objects clearly.
