optic zone diameter

optic zone diameter 

Diameter of the optic zone (front or back) of a contact lens measured to the surrounding junction. It is commonly specified in millimetres. Specifically, there are the back optic zone diameter (BOZD), formerly called back central optic diameter (BCOD), and the front optic zone diameter (FOZD). It is often difficult to measure these dimensions due to the blending of the line separating the zones, especially for the back optic zone diameter. The region surrounding the central optic zone is the peripheral zone. If there is more than one, the zones will be numbered first, second, etc., beginning with the zone immediately surrounding the central optic zone. The diameter of each peripheral zone is referred to as the back (or front) peripheral zone diameter (BPZD). See blending; total diameter; edge lift.
References in periodicals archive ?
Often the front optic zone diameter and BOZR are adjusted to reduce or increase the centre thickness (CT) to ensure suitable lens handling, optical performance and oxygen transmission.
Back optic zone diameter BOZD 00 Back/front peripheral B/FPZD 01,2.
Pupil size in average and low illumination--this influences back optic zone diameter (BOZD).
This measurement should be used as a guide to ensure the Back Optic Zone Diameter (BOZD) is greater than the largest pupil diameter.
a) Back optic zone radius (BOZR) and lens thickness b) Back optic zone radius (BOZR) and back optic zone diameter (BOZD) c) Back optic zone radius (BOZR) and back vertex power (BVP) d) Back optic zone diameter (BOZD) and lens thickness