Toric lenses are specifically designed for wearers with astigmatism. They have varying corrective powers on different parts of the lens. This helps correct visual irregularities associated with the imperfect curvature of an astigmatic eye. On the other hand, standard spherical lenses have uniform curvature across the entire surface of a lens. Because of the more complex design and fit, lenses for astigmatism correction are generally more expensive than spherical lenses.