FREE ABO-NOCE Verification of Progressive Lenses Questions and Answers

Question 1

What is the very first step an optician should take when placing a progressive addition lens (PAL) in a lensometer for verification?

Accepted Answer

Locate the semi-visible markings and engravings

Answer

Measure the add power immediately

Answer

Center the lens and check for prism

Answer

Focus the eyepiece of the lensometer

Question 2

To verify the distance prescription of a PAL, the lens should be positioned in the lensometer so that the mires are centered on the:

Accepted Answer

Distance reference point (DRP)

Answer

Fitting cross

Answer

Near reference point (NRP)

Answer

Geometric center of the lens

Question 3

How is the full add power of a progressive lens accurately measured with a lensometer?

Accepted Answer

By subtracting the distance sphere power from the near sphere power

Answer

By measuring the power at the fitting cross

Answer

By reading the temporal engraving on the lens

Answer

By measuring the power difference between the top and bottom edge of the lens

Question 4

While verifying a PAL, you notice that the reticle is displaced vertically at the prism reference point (PRP), even when the lens is correctly oriented. This indicates the presence of:

Accepted Answer

Prism-thinning (yoked prism)

Answer

An incorrect prescription

Answer

Unwanted horizontal prism

Answer

A warped lens

Question 5

The permanent markings engraved on a PAL, typically found nasally and temporally, are used to identify the:

Accepted Answer

Lens manufacturer and add power

Answer

Patient's pupillary distance

Answer

Optical center and fitting cross location

Answer

Recommended segment height

Question 6

What is the primary purpose of the fitting cross on a progressive lens?

Accepted Answer

To align the lens with the patient's pupil center

Answer

To verify the distance power

Answer

To measure the add power

Answer

To indicate the location of prescribed prism

Question 7

When neutralizing the near reference point (NRP) of a PAL, what is the correct procedure after measuring the distance power?

Accepted Answer

Move the lens up to center the NRP and re-focus the sphere mires

Answer

Rotate the axis wheel 90 degrees

Answer

Move the lens down to the bottom edge

Answer

Add prism to the lensometer reading