What feature distinguishes toric soft contact lenses from spherical lenses?

What feature distinguishes toric soft contact lenses from spherical lenses?

• A. Different powers in two meridians
• B. Edges are thicker for stability
• C. Higher water content
• D. They are always daily disposables

Answer: (A)

The key idea is that toric lenses are designed to correct astigmatism by having different refractive powers in two perpendicular directions. Because the eye’s curvature—and therefore its focusing strength—varies along different meridians, a toric lens incorporates a cylindrical component so one meridian has more power and the other has less. This lets the lens neutralize the uneven focus and produce clear vision. In contrast, spherical lenses have one uniform power in all directions, which can’t correct astigmatism.

Other statements aren’t defining features of toric versus spherical lenses. Edge thickness, water content, and wear schedule can vary widely by brand and design and don’t inherently distinguish toric from spherical.