Question

The eye defect, astigmatism can be corrected by using
(a) Convex lens
(b) Concave lens
(c) Cylindrical lens
(d) Surgery

Answer 1

Hint: It is a common condition in which the surface of the eye, or cornea, is not curved in the normal way, leading to the blurred vision which can be corrected by the lens that focuses light on the line and has various shapes.

Complete answer:
The abnormal curve on the cornea means that when light enters the eye, it is not correctly focused on the retina, resulting in an unclear image.
The eye defect, astigmatism can be corrected by using a spherical cylindrical lens. Astigmatism can change the way to pass light and thus causes blurry and distorted vision. It is characterized by the difficulty seeing at night, eyestrain, eye irritation, and headaches.
- The exact cause of astigmatism is still unclear but it is believed that genetic component plays a role in causing astigmatism
- When the light properly enters the eye, the perfectly curved cornea can bend, or refract it, but in the case of a person with astigmatism, the cornea is often egg- shaped with two different curves rather than perfectly round. This is sometimes known as corneal astigmatism.
- Because of the two different curves, the light ray will focus on two points on the retina instead of one. This causes blurry vision and sometimes double vision if the person has severe astigmatism.
- Preterm infants are highly susceptible to astigmatism as compared to those who have been born closer to their due date.
So, the correct answer is a ‘cylindrical lens’.

Note: No treatment is suggested if the astigmatism is mild. Otherwise, corrective lenses are the usual approach, corrective lenses bend the incoming light rays in a way that compensates for the error caused by faulty refraction.in this way images are properly projected on the retina. Some people may benefit from laser surgery.