What is astigmatism? How is it caused? How is it corrected? (OR) What is astigmatism and how is this vision defect counteracted?
Open in App
Solution
Astigmatism is a refraction error in which a person cannot simultaneously see both the horizontal and vertical views of an object with the same clarity. In this defect of vision, light rays fail to come from a single focus.
It can be corrected by using cylindrical lens which have different curvature in horizontal as well as in vertical direction.