the frame diffrence

What is the Frame Difference?

The difference between the horizontal (A) and vertical (B) measurements for the lens area of a frame.

How is the Frame Difference calculated?

Frame Difference = A - B, where A is the horizontal measurement and B is the vertical measurement.

What happens as the Frame Difference increases?

The surrounding box looks more rectangular.

What is the overall temple length?

The measurement from the barrel to the end of the temple of the frame.

How is the temple length measured in cable temples?

By stretching the flexible cable out and measuring with a ruler.

What does GCD stand for?

Geometric Center Distance.

How is GCD calculated?

GCD = eyesize + DBL.

If GCD is 72 mm and eyesize is 60 mm, what is the DBL?

DBL = 72 mm - 60 mm = 12 mm.

What is binocular decentration?

The difference between DBC (distance between centers) and binocular PD (pupillary distance).

If the DBC is 70 mm and the binocular PD is 62 mm, what is the binocular decentration?

The binocular decentration is 70 mm - 62 mm = 8 mm.

In monocular decentration, how is the DBC adjusted?

By dividing DBC by 2 and subtracting each of the monocular PDs.

What is the OD Decentration formula?

OD Decentration = DBC/2 - PDOD.

If the monocular DBC is 33 mm and the patient's OD PD is 31 mm, what is the OD Decentration?

OD Decentration = 33 mm - 31 mm = 2 mm in.

What does 'decentering the lens' refer to?

Moving the optical center away from the geometric center of the lens.

Why is accurate decentration important?

It ensures optimal optical performance and patient comfort, preventing prism-induced effects and visual fatigue.