Astigmatism

Q.

In a myopic eye, the image of a distant object is formed in front of retina and not at the retina itself. Why does this defect arise?

Q.

Astigmatism (for a human eye) can be removed by using ___.

1. Concave lens

2. Convex lens

3. Cylindrical lens

4. Prismatic lens

Q.

Why is there a change in the colour of the eye does it make some changes

Q. In an astigmatic eye, the shape of the cornea is ___. This defect is corrected using a ___ lens.

1. spherical, convex
2. oval, cylindrical
3. oval, convex
4. spherical, cylindrical

Q. For a normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens behind the cornea is 20D . using this information , the distance between the retina and the cornea-eye lens can be estimated

Q. Astigmatism is corrected usinglenses.

1. cylindrical
2. bifocal
3. translucent
4. convex

Q.

A combination of lenses made of different types of glass which do not produce spherical aberration are called

1. converging lenses

2. diverging lenses

3. anastigmat lenses

4. none of these

Q.

A person can see clearly only the objects situates in the range of 50 cm to 300 cm. He went to an Optometrist who prescribed him a lens of certain power to increase the maximum distance of his vision to infinity, i.e., it corrected the near sightedness. However, upon using the prescribed lens the person discovered that the near point of his vision has shifted from 50 cm to a distance ‘d’. What is the value of d?

Q.

The least distance of distinct vision is about for a healthy adult.

Q.

Give the technical term for an eye defect in which the cornea becomes uneven.

Q.

Fill in the blanks with correct words.

Astigmatism is corrected by using ________ or ________ lenses.

Q. What is astigmatism? How is it caused? How is it corrected? (OR)
What is astigmatism and how is this vision defect counteracted?

Q.

An eye defect in which cornea becomes uneven.

Q. The disease of astigmatism in human eye is because of:

1. unequal and uneven curvature of eye lens
2. eye lens being of organic matter
3. eye membranes being thick
4. opacity development in eye lens

Q. For a normal eye , the cornea of eye provides a converging power of 40 D & the least converging power of the eye lens behind the cornea is 20 D . Using this information , the distance between the retina & the cornea-eye lens is can be estimated to be 1) 2.5 cm 2) 1.67 cm 3) 1.5 cm 4) 5 cm

Q.

Choose the odd one out.

1. Rods

2. Cones

3. Rhodopsin

4. Cataract

Q.

Image is formed for the shortsighted person:

1. Behind retina

2. Eye lens

3. Before retina

4. At retina

Q. What do you understand by presbyopia and astigmatism?

Q. Write true or false for the following statements :
To correct astigmatism we use cylindrical lens.

1. True
2. False

Q. A person cannot see the lines drawn parallel to each other clearly. He is suffering from _________.

1. Presbyopia
2. Astigmatism
3. Myopia
4. Hypermetropia

Q.

For the myopic eye, the defect is cured by

1. Concave lens

2. Cylindrical lens

3. Convex lens

4. Any of the two lens

Q. How does cornea functions

Q.

In an astigmatic eye, the shape of cornea is ___. This defect is corrected using a ___ lens.

1. oval, cylindrical
2. spherical, cylindrical
3. Spherical, convex
4. oval, convex