Besides the base curve radius, what else can we measure for lens verification?

• A. Peripheral curve radius, front (convex) curve radius (front/bitoric lenses)
• B. Diameter
• C. Material
• D. Back surface radius

Answer: (A)

Beyond the back surface base curve, you can verify the other curved zones of a GP lens. The peripheral curve radii define how the lens sits on the eye and interacts with the eyelids, influencing comfort and movement. The front surface radius, especially for front-convex designs used in front/bitoric lenses, is measured because the front curve carries the optical correction and may differ in meridians for toric specifications. Checking these front and peripheral radii ensures the lens geometry matches the prescription, not just the base curve. Diameter and material are important, but they address size and composition rather than the front/edge geometry that affects fit and optics.