ABO NOCE Basic Opticianry Dispensing Instrumentation Questions and Answers

Question 1

An optician uses a lens clock to measure the front surface of a lens and gets a consistent reading of +6.50 D in all meridians. What does this measurement represent?

Accepted Answer

The base curve of the lens

Answer

The spherical equivalent of the lens

Answer

The total power of the lens

Answer

The cylindrical power of the back surface

Question 2

A patient's prescription is OD -8.50 D sphere. The original glasses were fit at a vertex distance of 14 mm, but the new, larger frame sits at 10 mm from the cornea. To ensure the patient experiences the correct prescribed power, the compensated lens power should be:

Accepted Answer

Less minus (e.g., -8.25 D)

Answer

More minus (e.g., -8.87 D)

Answer

The same (-8.50 D)

Answer

More plus (e.g., -8.12 D)

Question 3

When neutralizing a lens on a manual lensometer, you first focus the thin, single mires at +2.00 D with the axis wheel at 090. You then turn the power drum further into the plus to focus the thick, triple mires, which become clear at +3.50 D. What is the correct prescription in plus cylinder form?

Accepted Answer

+2.00 +1.50 x 090

Answer

+3.50 +1.50 x 180

Answer

+2.00 -1.50 x 090

Answer

+3.50 -1.50 x 180

Question 4

Which of the following instruments is specifically designed to measure the distance from the posterior surface of a spectacle lens to the apex of the cornea?

Accepted Answer

Distometer

Answer

Pupilometer

Answer

Lens Clock

Answer

Caliper

Question 5

An optician needs to make a significant adjustment to a thick zyl (cellulose acetate) frame temple. Which tool provides the most uniform and safest heat to make the material pliable without causing localized overheating or bubbling?

Accepted Answer

A salt pan with glass beads

Answer

A handheld butane torch

Answer

A hot water bath

Answer

A high-velocity hot air blower

Question 6

While verifying a pair of uncut lenses with a caliper, an optician is primarily measuring the:

Accepted Answer

Lens thickness

Answer

Base curve

Answer

Prismatic effect

Answer

Refractive index