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Question
Differentiate between myopia and hypermetropia.
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Solution
| Sr. No. | Myopia (Short-sightedness) | Hypermetropia (Long-sightedness) |
| 1. | A defect of vision because of which a person cannot see distant objects clearly. | A defect of vision because of which a person cannot see nearby objects clearly. |
| 2. | The far point of a myopic eye is closer than infinity. | The near point of a hypermetropic eye is more than 25 cm away. |
| 3. | Myopia occurs because the eye lens has a high converging power or because the eye ball is too long. | Hypermetropia occurs because the eye lens has a low converging power or because the eye ball is too short. |
| 4. | A person suffering from myopia should wear spectacles with concave lenses. | A person suffering from hypermetropia should wear spectacles with convex lenses. |
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The kind of lens required to correct Myopia
Name the defect of vision in a person:
whose near point is more than 25 on away.
What is the scientific name of
long-sightedness?
Name the body part with which the terms myopia and hypermetropia are connected.
Your friend can read a book perfectly well but cannot read the writing on blackboard unless she sits on the front row in class.
- Is she short-sighted or long-sighted?
- What type of lenses-converging or diverging-would an optician prescribe for her?
What are the two most common defects of vision (or defects of eye)? How are they corrected?
Explain with the help of labelled ray-diagram, the defect of vision called hypermetropia, and hot it is corrected by a lens.
A person having short-sight cannot see objects clearly beyond a distance of 1.5 m. What would be the nature and power of the corrective lens to restore proper vision?
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?
A person is unable to read a book placed closer than 1 meter from his eyes. Identify the defect of vision in his eyes. Draw the ray diagrams to show the defect of vision and its correction.
The near point of the eye of a person is 50 cm. Find the nature and power of the corrective lens required by the person to enable him to see clearly the objects placed at 25 cm from the eye?
The near point of the eye of a person is 50 cm. Find the nature and power of the corrective lens required by the person to enable him to see clearly the objects placed at 25 cm from the eye?
Complete the following sentence with appropriate word :
An inability to focus on nearby objects due to loss of elasticity of the lens with age is called Iris.
Mention, if the following statement is True or False
Hypermetropia is a defect of the eye caused due to the eyeball elongation
Observe the given below the figure, correct it and explain and write about the concept depicted in this figure.
Myopia and hypermetropia can be corrected by:
Assertion: Myopia is the defect of vision in which a person cannot see distant objects clearly.
Reason: This due to eye-ball being too short.
Observe the figure whether it is correct or not and explain the phenomenon.
