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प्रश्न
Name an old age eye defect. What happens in it?
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उत्तर
Presbyopia is an age-old eye defect. In this condition, the lens loses flexibility resulting in far-sightedness.
Cataract is also very common in old people, the cornea becomes opaque and the vision is cut down even to blindness.
संबंधित प्रश्न
List three common refractive defects of vision. Suggest the way of correcting these defects.
Name the defect of vision which makes the eye-lens cloudy resulting in blurred vision.
Name the defect of vision which can be corrected by a converging lens. Show clearly by a ray diagram how the lens corrects the defect.
What is short-sightedness? State the two causes of short-sightedness (or myopia). With the help of ray diagrams, show:
(i) the eye-defect short-sightedness.
(ii) correction of short-sightedness by using a lens.
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
Name the following:
The photosensitive pigment present in the rod cells of the retina.
Rewrite the following table so as to match second and third column with first column.
|
Column I
|
Column II
|
Column III
|
|
(i) Myopia
|
Old age problem
|
Bifocal lens
|
|
(ii) Presbyopia
|
Nearsightedness
|
Concave lens.
|
Give Technical Term:
The path which responsible for protecting the eye from sweat.
Mention, if the following statement is True or False
Hypermetropia is a defect of the eye caused due to the eyeball elongation
Given below is a diagram showing a defect of vision. Name the defect of vision and draw an accurately labelled diagram to correct this defect.
