What is Myopia? - Science and Technology 1


What is myopia?



Myopia or near-sightedness is the defect of vision in which a human eye can see nearby objects distinctly but is unable to see distant objects clearly. In this case, the image of a distant object is formed in front of the retina instead of on the retina.


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2012-2013 (March)



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.

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.

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?

A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?

Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.

Name the defect of vision in which the eye-lens loses its power of accommodation due to old age.

Name any two defects of vision which can be corrected by using spectacles.

Where is the near point of a person suffering from hypermetropia (or long-sightedness)?

Differentiate between myopia and hypermetropia. What type of spectacles should be worn by a person having the defects of myopia as well as hypermetropia? How does it help?

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?

Which part of the eye is grafted in a needy patient from a donated eye?

Describe the mechanism of focusing the image of a distant object in your eye when you raise your head after reading a book.

By closing the eyes and gently pressing them by your palms, you may see some specks of brilliant light. How do you get this sensation while there is no light entering your eyes?

Explain the terms ‘adaptation’ and ‘accommodation’ with reference to the eye.

What eye defect is hypermetropia? Describe with a ray diagram how this defect of vision can be corrected by using an appropriate lens.

Observer the following diagram and answer the questions.
a) Which eye defect is shown in this diagram?
b) What are the possible reasons for this eye defect?
c) How this defect is corrected, write it in brief?

Write whether the following is true or false:
A convex lens is used for correcting myopia.

Why does one feel blinded for a short while on coming out of a dark room?

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:

What are the two conditions shown in sections A and B of the eye as applicable to her?

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?

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
Concave lens.

Anuja cannot see the blackboard writing but she can see nearby things.
(a) What is the eye defect she is suffering from?
(b) State the possible reason for her defect.
(c) How is it corrected

In what two whys is a yellow spot different from the blind spot?

 Name the common defects of the eye.

Give Reason:

Why do we see clearly in the central region of the retina?

Give Reason:

When you enter into a dark room from bright because of sunlight, you can not see things for a few seconds.

Differentiate between:

Short-sightedness and Long-sightedness.

Explain the Term: Astigmatism

Give Technical Term:
The path which responsible for protecting the eye from sweat.

Given below is a diagrammatic representation of a defect of the human eye:

(i) Identify the defect.
(ii) Mention two reasons for the above defect.
(iii) State how the defect can be rectified.
(iv) Name the part of the eye responsible for maintaining the shape of the eyeball.

With respect to human eye explain:
(i) How is the image formed on the retina?
(ii) How is the amount of light entering the eye-controlled?
(iii) What type of lens is used for the correction of ‘Long sight’ defect?
(iv) With the help of a ray, diagram show the defect of the eye and then its correction after the use of a lens.

 Choose the Odd One Out: 

In Myopia the human eye _______.

Due to elongation of _______ and increase in curvature of the eye lens, a person cannot see distant objects clearly.

Nearsightedness : concave lens : : farsightedness : _______

Write scientific reason.

Nearsightedness, this defect can be corrected by using spectacles with concave lens.

Observe the given below the figure, correct it and explain and write about the concept depicted in this figure.

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.

What are the causes of ‘Myopia’?

Differentiate the eye defects: Myopia and Hypermetropia

Assertion: Concave mirrors are used as reflectors in torches, vehicle head lights and in search lights.

Reason: When an object is placed beyond the center of curvature of a concave mirror, the image formed is real and inverted.

Which of the following statement is correct?

Correlate the given sequence:

Hypermetropia : Convex lens : ______ : Concave lens

Observe the figure whether it is correct or not and explain the phenomenon.

Observe the figure and answer the following questions: 

  1. Name the defect of vision represented in the above figure.
  2. State the reasons for this defect.
  3. How is it corrected?
  4. Draw the diagram to show the correction of this defect.

Match the following:

Column - I Column - II
1. Retina a. Path way of light
2. Pupil b. Far point comes closer
3. Ciliary muscles c. near point moves away
4. Myopia d. Screen of the eye
5. Hypermetropia e. Power of accommodation

Complete the following table by observing the given figure:

Figure →
Points ↓
(a) Name of the defect ____________ ____________
(b) Position of the image ____________ ____________
(c) Lens used to correct the defect ____________ ____________


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