Astigmatism is corrected by the use of which lens?

Correct option is B

The correct answer is (b) Cylindrical lens

Explanation:

. Astigmatism is a vision defect where the eye does not focus light evenly on the retina due to an irregularly shaped cornea or lens.

. In an astigmatic eye, the curvature of the cornea is different in different planes, leading to blurred or distorted vision at all distances.

. It is corrected using Cylindrical lenses, which have different focal lengths in different planes to compensate for the eye's irregularity.

. These lenses direct light specifically to the points where the cornea is failing to focus it correctly.

. Astigmatism often occurs in combination with other refractive errors like myopia (nearsightedness) or hypermetropia (farsightedness).

Information Booster:

. Modern spectacle prescriptions for astigmatism include three values: Sphere, Cylinder, and Axis.

. The Axis indicates the orientation of the cylindrical power needed to correct the vision.

Additional Knowledge: Double concave lens (Option a)

. Primarily used in specialized optical instruments or high-power corrections for severe myopia.

Convex lens (Option c)

. Used to correct Hypermetropia (Long-sightedness) and Presbyopia, as it helps in converging light rays earlier onto the retina.

Concave lens (Option d)

. Used to correct Myopia (Near-sightedness) by diverging light rays so the image forms correctly on the retina rather than in front of it.