Which design is appropriate for a patient requiring correction tо moderate astigmatism?

The posterior toric design is specifically engineered to address astigmatism, especially in cases of moderate astigmatism. This design incorporates differing curvatures on the lens surface, which allows for the correction of the refractive error caused by the irregular shape of the cornea or lens in astigmatic eyes.

When dealing with moderate astigmatism, the goal is to create a lens that can effectively align with the two principal meridians of the eye, which differ in power. The posterior toric design achieves this by providing the necessary power in both the vertical and horizontal orientations, thus ensuring that light is focused correctly on the retina.

Other designs mentioned, such as a standard spherical lens, may not be suitable for a patient with moderate astigmatism, as they do not account for the varying degrees of curvature present in the cornea. Anisometropic designs cater to patients with different refractive errors between the two eyes, which doesn’t specifically address astigmatism. Multifocal lenses are intended to assist with presbyopia and are not designed primarily to correct astigmatism. Thus, the posterior toric design is the most appropriate choice for effectively managing moderate astigmatism and providing optimal vision correction