NOCE Spectacle Dispensing Procedures 2 — Questions and Answers
Question 1: When adjusting temples for a patient with asymmetrical ears, which measurement is most critical?
- Vertex distance
- Temple length to bend (Correct answer)
- Frame PD
- Bridge width
Correct answer: Temple length to bend
The temple length to bend must be individually set for each ear to ensure the frame sits level on an asymmetrical face.
Question 2: A patient complains that new progressive lenses feel like they are 'swimming.' The most likely cause is:
- Incorrect back vertex distance
- Incorrect corridor length for the frame (Correct answer)
- Pantoscopic tilt too steep
- Segment height too low
Correct answer: Incorrect corridor length for the frame
A corridor that is too long or short for the patient's frame causes the swim effect because the optical zones are misaligned with the visual axis.
Question 3: Which tool is used to measure the distance between the back surface of a lens and the patient's cornea?
- Pupillometer
- Distometer (Correct answer)
- Lensometer
- Geneva lens clock
Correct answer: Distometer
A distometer (also called a vertex distance gauge) measures the back vertex distance from the lens to the corneal apex.
Question 4: When a plastic frame is too tight at the temples, the correct adjustment involves:
- Heating the frame and spreading the temples (Correct answer)
- Filing the nose pads
- Bending the frame front downward
- Tightening the hinge screws
Correct answer: Heating the frame and spreading the temples
Plastic frames must be heated to their softening point before widening the temples to avoid cracking the material.
Question 5: A patient's bifocal segment consistently drops below the lower lid margin after dispensing. The dispenser should:
- Increase pantoscopic tilt
- Raise the segment height by adjusting the nose pads (Correct answer)
- Reduce the face form angle
- Decrease vertex distance
Correct answer: Raise the segment height by adjusting the nose pads
Raising the nose pads lifts the frame and moves the segment upward to the proper position at or just below the lower lid.
Question 6: For a patient with a high minus prescription, which frame characteristic minimizes unwanted prismatic effects and lens thickness?
- Large eye size with high wrap
- Small eye size with minimal decentration (Correct answer)
- Rimless with extended temples
- Large bridge with low pantoscopic tilt
Correct answer: Small eye size with minimal decentration
A small eye size reduces the amount of lens needed and minimizes edge thickness and prism induced by decentration in minus lenses.
Question 7: According to ANSI Z80.1 standards, what is the maximum allowable tolerance for sphere power in a finished single vision lens (for powers up to ±6.50 D)?
- ±0.06 D
- ±0.13 D (Correct answer)
- ±0.25 D
- ±0.50 D
Correct answer: ±0.13 D
ANSI Z80.1 allows ±0.13 D tolerance for sphere power in single vision lenses with powers up to ±6.50 D.
NOCE Spectacle Dispensing Procedures 2
When adjusting temples for a patient with asymmetrical ears, which measurement is most critical?