Given frame measurements A=65mm, B=56mm, DBL=15mm, and a customer Distance PD of 60mm, what is the monocular decentration calculated?

To determine the monocular decentration when given specific frame measurements and a customer distance PD (pupillary distance), we start by understanding the inputs. The frame measurements provided include the A measurement (the width of the lens) and the B measurement (the height of the lens), along with the DBL (distance between lenses, or bridge width).

In this particular calculation, we need to find the difference between the customer's distance PD and the total width of the frame measured in millimeters. The formula to find monocular decentration for each eye is given by:

Monocular Decentration = (Frame PD - Customer PD) / 2.

1. The total frame PD can be computed as the A measurement plus the DBL. This gives us:

Total Frame PD = A + DBL = 65mm + 15mm = 80mm.

2. Next, we compare this total frame PD to the customer's distance PD:

Difference = Total Frame PD - Customer PD = 80mm - 60mm = 20mm.

3. Since monocular decentration is calculated per eye, we divide this difference by 2:

Monocular Decentration = 20mm / 2 =