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प्रश्न
Give Reason:
Older people require glasses to read and write.
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उत्तर
In old age the flexibility of the lens declines and the lens becomes less convex or opaque leading to weakness of eyesight.
संबंधित प्रश्न
Do you know that the corneal-impairment can be cured by replacing the defective cornea with the cornea of the donated eye? How and why should we organise groups to motivate the community members to donate their eyes after death?
Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.
Name the defect of vision in a person:
whose near point is more than 25 on away.
Name the defect of vision in which the eye-lens loses its power of accommodation due to old age.
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
State the main functions of the following:
Tears
When do we consider a student sitting in the class to be myopic? List two causes of this defect. Explain using a ray diagram how this defect of eye can be corrected.
Name the following:
The photosensitive pigment present in the rod cells of the retina.
Given alongside is a diagram depicting a defect of the human eye. Study the same and then answer the questions that follow:

- Identify the defect.
- Name the parts labelled 1, 2 and 3.
- Give two possible reasons for this eye defect.
- Draw a labelled diagram to show how the above mentioned defect is rectified.
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.

