Cylindrical lenses are used to correct:
Related question: Which of the following transpositions is the correct one?
Answer: Cylindrical lenses are used to correct Astigmatism. A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would. The curved face or faces of a cylindrical lens are sections of a cylinder, and focus the image passing through it into a line parallel to the intersection of the surface of the lens and a plane tangent to it.