ABO MATH EQUATIONS 26-27

Calculate per-lens decentration: Frame A = 52mm, DBL = 18mm, Patient PD = 62mm

4 mm inward per lens

Frame PD = A + DBL = 52 + 18 = 70mm. Decentration per lens = (70 - 62) / 2 = 4mm inward.

Seg height calculation: Patient OC height is 24mm, frame B = 42mm, seg drop needed = 5mm. What seg height should be ordered?

19 mm

Seg height = OC height - seg drop. Seg drop is measured from OC.

Minimum blank size calculation: Frame A = 54mm, Frame B = 40mm, ED = 58mm, Decentration = 5mm. What minimum blank diameter is needed?

68 mm

MBS = 58 + (2 × 5) + 2

MBS = 58 + 10 + 2 = 70mm

Patient has monocular PDs: OD 31mm, OS 33mm. Frame GC (geometric center) is 35mm from bridge center each side. Calculate decentration for each lens.

od: 4mm os: 2mm

Calculate per-lens decentration: Frame A = 52mm, DBL = 18mm, Patient PD = 62mm

4 mm inward per lens

Frame PD = A + DBL = 52 + 18 = 70mm. Decentration per lens = (70 - 62) / 2 = 4mm inward.

Frame PD is 70mm, patient PD is 64mm. How much total decentration is needed in total and per lens?

6mm total (3mm per lens)