Which type of lens is required to correct astigmatism?

The type of lens required to correct astigmatism is toric lenses. Astigmatism is a condition caused by an irregular curvature of the cornea or lens, leading to blurred or distorted vision. Toric lenses are specifically designed with different optical powers and curvatures in different meridians, which allows them to correct the uneven curvature of the eye effectively.

Unlike spherical lenses, which have a uniform curvature and are used primarily for myopia or hyperopia correction, toric lenses can address the specific curvature needed for each eye's unique astigmatism. Multifocal lenses are designed for individuals who require vision correction at multiple distances but are not specially tailored for astigmatism. Convex lenses are typically used to correct hyperopia (farsightedness) and do not cater to the complexities of astigmatism. Therefore, toric lenses are the correct option as they specifically accommodate the unique requirements of astigmatism correction.