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)

Toric soft lenses are built to correct astigmatism, which means they must provide different refractive powers in two principal meridians. One meridian carries a cylindrical power plus the spherical power, while the perpendicular meridian has a different (typically just the spherical) power. That difference in powers along different directions is what distinguishes toric lenses from spherical lenses, which have the same power in every meridian.

Because astigmatism is orientation-specific, toric lenses also rely on designs or features to keep the lens aligned with the eye’s axis, but the key distinction remains the two meridians with different powers. Spherical lenses, on the other hand, correct only myopia or hyperopia with identical power in all directions.

Other statements—being made with higher water content or being always daily disposables—aren’t defining traits of toric lenses, since torics can use a range of materials and replacement schedules.