Which one of the following lenses should be used to correct the defect of astigmatism ? (a)Cylindrical lens (b)Concave lens (c)Convex lens (d)Bifocal lens
option A Astigmatism is corrected the use of cylindrical lenses. Hypermetropia is corrected the usage of convex lens which movements the photo to the retina which become in advance forming past retina. Presbyopia is corrected the use of bifocal lens i.e. a aggregate of a convex lens and a concave lens.
