Which term denotes the diameter of the central optical zone on a GP lens?

Which term denotes the diameter of the central optical zone on a GP lens?

• A. Optical Zone Diameter
• B. Optical Zone Depth
• C. Overall Zone Diameter
• D. Outer Zone Diameter

Answer: (A)

Optical Zone Diameter is the width of the central optical region of a gas-permeable lens where the refractive power is uniform. This central patch sits over the pupil and cornea to provide the intended vision correction, so its diameter defines how broad that corrective area is from edge to edge. The overall diameter refers to the entire lens, not just the central zone, and the other terms describe different aspects (like depth or peripheral zones) rather than the central optical region. So the term that denotes the diameter of the central optical zone is Optical Zone Diameter.

Optical Zone Diameter is the width of the central optical region of a gas-permeable lens where the refractive power is uniform. This central patch sits over the pupil and cornea to provide the intended vision correction, so its diameter defines how broad that corrective area is from edge to edge. The overall diameter refers to the entire lens, not just the central zone, and the other terms describe different aspects (like depth or peripheral zones) rather than the central optical region. So the term that denotes the diameter of the central optical zone is Optical Zone Diameter.