Spectacle Dispensing Procedures 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 Spectacle Dispensing Procedures flashcards as text
A patient receives a prescription of -0.50 – 2.00 x 090. When verifying with the lensometer, the cylinder axis should be confirmed at:
Answer: 090 degrees
The cylinder axis in the prescription is 090°, and lensometer verification must confirm the cylinder power is oriented at exactly that axis.
Prism thinning is a technique used primarily to:
Answer: Equalize the center thickness of lenses with different powers
Prism thinning (slab-off or base-up prism) compensates for the differential prismatic effect in anisometropic corrections, but in lens fabrication, 'prism thinning' typically refers to equalizing thickness.
When dispensing a frame with a wrap angle greater than 5°, prescriptions above ±2.00 D may require:
Answer: Compensated lens powers to account for oblique incidence
High wrap angles cause the lens to be tilted relative to the visual axis, requiring power compensation (tilt-induced sphere and cylinder) to maintain optical accuracy.
The effective diameter (ED) of a lens is:
Answer: The smallest circle that will completely enclose the lens shape
The effective diameter is the diameter of the smallest circle that entirely encloses the lens shape, used to determine minimum blank size needed.
A frame's DBL (distance between lenses) is 20 mm and a patient's bridge width is 14 mm. This frame will likely:
Answer: Slip down and sit too wide on the face
A DBL much wider than the patient's bridge width will cause the frame to rest too low and slide down, since the bridge won't be supported by the nose.
Which of the following is the correct sequence for dispensing new eyeglasses to a patient?
Answer: Verify Rx → adjust frame to patient → instruct patient on care and use
Best dispensing practice requires verifying the prescription accuracy first, then fitting/adjusting the frame to the patient, and finally educating the patient on lens and frame care.
A patient reports that their new glasses feel 'swimmy' (objects appear to move). This is most commonly caused by:
Answer: A significant change in prescription or incorrect pantoscopic tilt with progressive lenses
Peripheral distortion described as 'swimmy' is often due to adaptation to a new prescription or an incorrect pantoscopic tilt in progressives, which misaligns the corridor.