ABO NOCE Basic Opticianry Verification of Progressive Lenses 4

Question 1

Which measurement is used to determine if a progressive lens has been correctly positioned for the correct seg height after dispensing?

Accepted Answer

Measuring from the lower rim to the fitting cross with the patient wearing the frame

Answer

Seg height for progressives is confirmed by measuring from the lower rim (or lowest point of the frame) to the center of the pupil while the patient wears the frame in its adjusted position.

Question 2

A short-corridor progressive lens design has which of the following characteristics compared to a long-corridor design?

Accepted Answer

A shorter distance from the fitting cross to the full near power zone

Answer

Short-corridor designs have a shorter distance from the fitting cross to where full near power is reached, making them suitable for smaller frames.

Question 3

When verifying progressive lenses with a lensometer, which zone should be used to verify the cylinder power and axis?

Accepted Answer

The distance reference point (DRP)

Answer

Cylinder power and axis are verified at the distance reference point (DRP) because the distance zone contains the full prescribed cylinder.

Question 4

According to ANSI Z80.1, what is the maximum allowable vertical prismatic imbalance between the two progressive lenses at the distance reference point?

Accepted Answer

0.33 prism diopters

Answer

ANSI Z80.1 allows a maximum vertical prismatic imbalance of 0.33 prism diopters between the two lenses at the distance reference point.

Question 5

A progressive lens is ordered with no prescribed prism, but during verification, 0.5Δ base-down is measured at the PRP of the right lens. This finding is:

Accepted Answer

Outside ANSI tolerance and the lens should be remade

Answer

When no prism is prescribed, 0.5Δ at the PRP exceeds the ANSI Z80.1 tolerance of 0.33Δ vertical or 0.67Δ horizontal, so the lens must be remade.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Verification of Progressive Lenses 4