Question

A disease, in which eye lens becomes cloudy and opaque lens is removed and a new artificial lens is inserted, is:
A. Hypermetropia
B. Astigmatism
C. Cataract
D. Near-sightedness

Answer 1

Hint:To answer this question, you have to check every option. Hypermetropia is also known as far-sightedness. A person with myopia is able to see the nearby objects but unable to see the far objects clearly. Astigmatism is caused by irregular shape of the cornea.

Complete answer:
To answer this question, let us discuss each option one by one as follows,
Hypermetropia: It is also known as far-sightedness. The person suffering from hypermetropia is able to see the far objects but unable to see nearby objects clearly. In that case, the far point of the eye increases to a greater distance than distance of distinct vision (25 cm). We know that this disease can be cured using a convex lens of suitable focal length.

Astigmatism: In an eye with astigmatism, the parallel rays from the object do not focus at a single point onto the retina rather they focus in front of the retina or behind the retina. In that case, the vision becomes unclear due to multiple focal points. We know that astigmatism is usually caused by irregular shape of a cornea.

Near-sightedness: Nearsightedness is also called Myopia. A person with myopia is able to see the nearby objects but unable to see the far objects clearly. We know that myopia can be cured using a concave lens of suitable focal length.

Cataract: A cataract is a dense and cloudy layer formed on the eye which blocks the vision. It develops slowly in old age. To cure the cataract, the cloudy lens of the eye is replaced with a new artificial lens. Thus, A disease, in which eye lenses become cloudy and opaque lenses are removed and a new artificial lens is inserted, is known as cataract.

So, the correct answer is option C.

Note:To answer these types of questions, students must memorize all the eye related diseases and how can they be cured. Also, students must be able to identify the nature of the lens required to cure the mentioned diseases. The cataract cannot be cured with the use of spectacles. The specific eye operation is needed.