Dispensing Instrumentation Questions and Answers Flashcards
7 cards from real ABO NOCE Basic Opticianry practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Dispensing Instrumentation Questions and Answers flashcards as text
Which of the following tools is specifically designed to measure the thickness of a spectacle lens?
Answer: Lens thickness gauge (caliper)
A lens thickness gauge or caliper directly measures the physical thickness of a lens at any specified point.
When using a lensmeter to measure a bifocal lens, the reading through the segment gives the:
Answer: Near power only
Reading through the bifocal segment on the lensometer yields the total near power; the add power is calculated as near power minus distance power.
The marking dots applied by the lensometer's ink marking device indicate the:
Answer: Optical center location and axis orientation
The three dots marked by the lensometer's marker show the optical center (center dot) and the horizontal reference axis (outer dots) of the lens.
A frame aligner (frame alignment tool) is most useful for correcting:
Answer: Pantoscopic tilt and face-form angle of frames
Frame aligners allow the dispenser to measure and correct pantoscopic tilt and face-form wrap to ensure proper fit and optical performance.
In lensometry, the difference in drum readings between the two focal lines of a cylindrical lens indicates the:
Answer: Cylinder power
The numerical difference between the two power drum readings when each focal line is clear represents the cylinder power of the lens.
A PD ruler (millimeter rule) is most appropriately used to measure:
Answer: Monocular and binocular pupillary distances using a reference point
A PD ruler placed across the bridge of the nose allows the dispenser to measure pupillary distances using a corneal reflex or pupil center as a reference.
Which instrument would best verify that a finished lens has the correct amount of induced prism?
Answer: Lensometer with prism reticle
The lensometer can measure prism power and direction by observing displacement of the target from the center of the reticle.