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प्रश्न
List three common refractive defects of vision. Suggest the way of correcting these defects.
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उत्तर
The three common refractive defects of vision are as follows:-
Myopia (short-sightedness):- It is corrected by using spectacles having concave lenses of appropriate power.
Hypermetropia (far-sightedness):- It is corrected by using spectacles having convex lenses of appropriate power.
Presbyopia:- This defect is corrected using bifocal lenses of appropriate power in which the upper part consists of a concave lens (to correct myopia) and the lower part consists of a convex lens (to correct hypermetropia).
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संबंधित प्रश्न
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
From which defect of the eye is he suffering?
Differentiate between myopia and hypermetropia. What type of spectacles should be worn by a person having the defects of myopia as well as hypermetropia? How does it help?
A person suffering from the eye-defect myopia (short-sightedness) can see clearly only up to a distance of 2 metres. What is the nature and power of lens required to rectify this defect?
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 a young man
Name an old age eye defect. What happens in it?
Name an old age eye defect. Why is it caused?
Name the following:
The defect of the human eye caused due to the uneven surface of the cornea.
Give Technical Term:
The path which responsible for protecting the eye from sweat.
What are the causes of ‘Myopia’?
State reasons for Myopia. With the help of ray diagrams, show the:
- image formation by a myopic eye, and
- correction of myopia using an appropriate lens.
