Define astigmatism.How it is corrected?

1.	Define astigmatism.How it is corrected?
Answer» Defect of eye in which vertical and horizontal lines are not visible. It is corrected by using cylindrical lens. In astigmatism, both vertical and horizontal lines are not focused properly.It is due to the effect on the curvature of the cornea or lens.It is corrected by using cylindrical lens.

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