Defects of Vision

Q. A person cannot see beyond 2 m. If he has to read a signboard 4 m away, then the power of the lens required is

1. 0.25 D
2. -0.25 D
3. 0.75 D
4. -0.75 D

Q. A person is not able to see the object at the distance more than 40 cm from his eye. In order to see the object clearly, he must use the lens of power

1. –40 D
2. +40 D
3. –2.5 D
4. +2.5 D

Q. A person cannot see any object placed beyond 50cm from his eye. Calculate the power of the lens which will enable him to see the distant stars clearly.

1. -1 D
2. +1 D
3. +2 D
4. -2 D

Q. What is the cause of cataract and how it can be corrected?

1. Cause: Irregular shape of cornea
   Correction: By surgery
2. Cause: Formation of membrane over the eye lens
   Correction: By using cylindrical lens
3. Cause: Irregular shape of cornea
   Correction: By using cylindrical lens
4. Cause: Formation of membrane over the eye lens
   Correction: By surgery

Q. The near point of a person is 75cm. In order that he may be able to read book at a distance 30cm. The power of spectacles lenses should be

1. -2 D
2. + 3.75 D
3. +2 D
4. + 3 D

Q. For how long does an image persist on the retina?

1. 0.0125 seconds
2. 0.0625 seconds
3. 0.04 seconds
4. 0.05 seconds

Q.

Explain the term ‘Cataract’.

Q.

Which part of the eye gets affected if someone suffers from a cataract? How is it treated?

Q. A person cannot see nearer than 1.5 m. If he has to read a signboard 40 cm away, then the power of the lens required is

1. 0.25 D
2. 1.83 D
3. 0.75 D
4. –0.75 D

Q. In case of myopia, the image is formed beyond retina.

1. False
2. True

Q. In a myopic eye, the image of a distant object forms .

Q. Presbyopia is corrected using lenses.

1. concave
2. convex
3. bifocal

Q. Owls have a better night vision but poorer colour perception than humans due to _______ and ______ respectively, in their eyes.

Q. What are the symptoms of Astigmatism?

1. Difficulty in sighting distant objects
2. Decrease in vision of eye
3. Difficulty in sighting nearby objects
4. Blurred vision and eye strain

Q. Identify the optical aids for the visually impaired.

1. Auditory aid
2. Telescopic aid
3. Braille script
4. Spectacles
5. Contact lenses
6. Guide dog
7. Magnifier
8. Bifocals
9. Electronic aid

Q. In case of myopia, the image is formed beyond retina.

1. False
2. True

Q. What are the symptoms of Astigmatism?

Q. Presbyopia is corrected using lenses.

1. bifocal
2. convex
3. concave

Q. Near point and Far point for a person’s eye is decided by the range of power an eye lens has.

1. True
2. False

Q. Explain different types of vision defects and their rectification.

Q. When you are looking at the objects closer to the eye, the focal length of eye lens:

1. remains the same
2. increases
3. decreases
4. peaks to infinity

Q. When you are looking at the objects closer to the eye, the focal length of eye lens:

1. increases
2. decreases
3. peaks to infinity
4. remains the same

Q. Astigmatism results in eye strain. What exactly happens in astigmatism?

1. Decrease in vision of eye
2. Difficulty in sighting distant objects
3. Difficulty in sighting nearby objects
4. Inability to focus on horizontal and vertical lines simultaneously

Q. Presbyopia is corrected using lenses.

1. concave
2. bifocal
3. convex

Q.

Explain Cataract

Q. In case of myopia, the image is formed beyond retina.

1. True
2. False

Q. Discontinuity of images of a movie can be identified by the brain when:

1. Frame rate < 16
2. Frame rate = 16
3. Frame rate > 16
4. None of these