Which design is characterized as having both front and back toric surfaces?

The design characterized as having both front and back toric surfaces is known as the bitoric lens. This type of lens is specifically engineered to address astigmatism by incorporating toricity in both surfaces, which enhances the lens's ability to focus light accurately onto the retina. This dual-toric design allows for optimal correction of spherical and cylindrical errors, making it particularly effective for individuals with complex astigmatic prescriptions.

In contrast, other types of lenses, such as monocular lenses, typically do not feature both front and back toric surfaces; they are single-vision lenses. Similarly, front toric lenses only have a toric surface on the front, and back toric lenses have a toric surface on the back, lacking the comprehensive correction that a bitoric lens provides. This distinction is crucial for providing the best visual clarity for patients with astigmatism.