write an article about the different defects are caused in vision. class 8 physics
Answers
Explanation:
As we know, human eyes are slowly losing their accommodating power and person can not see clearly and comfortably in these situations. There are three main eye abnormalities, and they are
Myopia (near-sightedness
Far-sightedness or hypermetropia, and
Presbyopia.
By the use of appropriate spherical lenses, these defects are fixed.
Myopia
Myopia is also referred to as short-sightedness or near-sightedness.
What occurs is that light rays do not focus on the surface of the retina, but it focus just in front of it. When perceived, this results in images being blurry.
In such a scenario, distant objects appear out of sight, but close objects are visible. It is the reason why close or short-sightedness is often called myopia.
- As we know that the mismatch between corneal shape and eye length
cause defects.
- It is also called refractive errors.
- which means problems in the refraction of the light by the cornea.
- So due to this light is not focused on the retina.
- There are the following defects of vision,
Presbyopia.
Farsightedness.
Near-sightedness.