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प्रश्न
Explain the Term: Astigmatism
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उत्तर
Astigmatism: It is a defect in which some parts of the object are seen in focus while others are blurred. It arises due to the uneven curvature of the cornea. This is corrected by cylindrical lenses.
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संबंधित प्रश्न
Given below is a diagram showing a defect of human eye. Study it and answer the following questions.
(i) Name the defect shown in the figure.
(ii) Give reason for this defect of eye in human being.
(iii) Name the type of lens used to correct the eye defect.
What is the far point and near point of the human eye with normal vision?
What are the two most common defects of vision (or defects of eye)? How are they corrected?
An eye has a far point of 2 m. What type of lens in spectacles would be needed to increase the far point to infinity? Also calculate the power of lens required. Is this eye long-sighted or short-sighted?
Name the following:
The eye defect caused due to shortening of the eye ball from front to back.
Select the odd one in the following series:
Endolymph, Tympanic membrane, Semi-circular canal, Blind spot.
Have a look at the posture of this woman who is reading a book and answer the questions which follow:
What kind of looking glasses she needs?
Give Reason:
Deficiency of vitamin A causes night blindness.
What type of lens is used to correct Astigmatism?
Myopia and hypermetropia can be corrected by:
