Question

Explain the following terms used in relation to defects in vision and correction provided by them:
(i) Myopia (ii) Astigmatism (iii) Bifocal lenses (iv) Far-sightedness.

Answer 1

HEY BHIYAA !!!

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1) MYOPIA :-

Myopia is defect of vision in which a a person cannot see clearly at a distant object and can see nearly object clearly.

is called myopia.

myopia is also known as short sightedness.

cause of myopia :-

1) myopia is caused by decrease in focal length of eye lens.

correction:-

myopia can be corrected by using the suitable spectacles made of concave lens.

2) astigmatism:-

it is generally take place because due to curvature of cornea.

astigmatism can be cured by surgery or operation.

3) Bifocal lens:-

it is a type of lens which is used to cure the pres byopia
.

press by opia is a defect of vision in which old person cannot see near object as well as far objects clearly.

or we can say that in simple ways it is a loose the power of accommodation.

the power of accommodation that is 25 CM.

4) far sightedness:-

hypermetropia is also known as far sightedness or long sightedness.

it is defect of vision in which an eye is not able to see clearly nearby object and can we see distant object clearly.

cause:-

it is caused due to increase in focal length of eye lens.

correction:-

this type of vision can be removed by using the spectacles made of convex lens.

hope it helps!!!!

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thanks

Answer 2

Hello.....

Myopia
It is a condition in which close objects appear clearly,but far one's don't .
Also called as near sightedness or short sightedness.

Astigmatism
A defect in the eye or in a lens caused by a deviation from spherical curvature,which results in distorted images,as light rays are prevented from meeting at a common focus.

Bifocal lenses..

Also called as bifocals.Bifocals are eyeglasses with two distinct optical powers.Bifocals are commonly prescribed to people with presbyopia.

Far sightedness

A vision condition in which nearby objects are blurry. Also commonly known as hypermetropia. People suffering from hypermetropia can see far objects clearly.

Thanks.....