Spectacle Dispensing Procedures Flashcards

When adjusting temples for a patient with asymmetrical ears, which measurement is most critical?

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.

A patient complains that new progressive lenses feel like they are 'swimming.' The most likely cause is:

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.

Which tool is used to measure the distance between the back surface of a lens and the patient's cornea?

Answer: Distometer

A distometer (also called a vertex distance gauge) measures the back vertex distance from the lens to the corneal apex.

When a plastic frame is too tight at the temples, the correct adjustment involves:

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.

A patient's bifocal segment consistently drops below the lower lid margin after dispensing. The dispenser should:

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.

For a patient with a high minus prescription, which frame characteristic minimizes unwanted prismatic effects and lens thickness?

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.

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)?

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.