FREE National Opticianry Competency Exam (NOCE) Optical Instrumentation Use 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 +6.00 D in all meridians.
When measuring the back surface, the reading is -8.00 D in the 180° meridian and -6.00 D in the 090° meridian.
Assuming the lens clock is calibrated for an index of 1.53 and the lens material is crown glass (n=1.523), what is the nominal prescription of this lens in minus cylinder form?

Accepted Answer

+0.00 -2.00 x 090

Answer

+0.00 -2.00 x 180

Answer

-2.00 -2.00 x 090

Answer

-2.00 +2.00 x 180

Question 2

When using a corneal reflex pupillometer to take a monocular pupillary distance (PD) measurement for progressive addition lenses, which of the following is a critical step for ensuring accuracy?

Accepted Answer

Ensuring the patient and dispenser are seated and at eye level with each other.

Answer

Having the patient converge their eyes as if reading.

Answer

Measuring from the center of the right pupil to the temporal limbus of the left eye.

Answer

Setting the instrument's fixation distance to infinity for all measurements.

Question 3

A client's new high-plus power eyeglasses are verified to be correct in the lensometer, but the client reports blurry vision. The original refraction was performed at a vertex distance of 12 mm, but the new frames sit 16 mm from the patient's cornea. Which instrument should be used to measure this discrepancy, and what is the likely effect on the perceived power?

Accepted Answer

Distometer; an increase in perceived plus power.

Answer

Pupillometer; a decrease in perceived plus power.

Answer

Lens Clock; an increase in perceived plus power.

Answer

Geneva Lens Gauge; a decrease in perceived plus power.

Question 4

An optician is preparing to adjust a pair of cellulose acetate frames for a patient. Which of the following instruments is most appropriate for making the frame material pliable, and what is a key precaution to take?

Accepted Answer

A hot air frame warmer; avoid concentrating heat in one spot to prevent damage.

Answer

An ultrasonic cleaner; ensure the frame is fully submerged.

Answer

Axis pliers; use firm pressure to reshape the bridge.

Answer

A salt pan; use the highest temperature for rapid softening.

Question 5

Before neutralizing an unknown lens in a manual lensometer, what is the first and most critical step the operator must perform?

Accepted Answer

Focus the eyepiece for their own eye.

Answer

Set the axis wheel to 90 degrees.

Answer

Place the lens on the stage with the concave side up.

Answer

Turn the power drum until it reads -10.00 D.

Question 6

Which of the following instruments is used to measure the base curve of a finished spectacle lens?

Accepted Answer

Lens Clock

Answer

Pupillometer

Answer

Distometer

Answer

Lensometer