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Question
Name an old age eye defect. What happens in it?
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Solution
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.
RELATED QUESTIONS
In a Std. X class out of 40 students 10 students use spectacles, 2 students have positive power and 8 students have negative power of lenses in their spectacles.
Answer the following questions:
(1) What does the negative power indicate?
(2) What does the positive power indicate?
(3) Generally which type of spectacles do most of the students use?
(4) What defect of eyesight do most of the students suffer from?
(5) Give two possible reasons for the above defect.
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(a) astigmatism
(b) myopia
(c) presbyopia
(d) hypermetropia
Describe the mechanism of focusing the image of a distant object in your eye when you raise your head after reading a book.
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State one role of ciliary muscles in the human eye.
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow :
Name the type of lens used to correct this eye defect.
Have a look at the posture of this woman who is reading a book and answer the questions which follow:
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(b) State the possible reason for her defect.
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