Spectacle Dispensing and Fitting Flashcards
6 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 6 Spectacle Dispensing and Fitting flashcards as text
A patient complains that the bottom edge of their new glasses is touching their cheeks, especially when they smile. Which of the following adjustments is the most effective first step to resolve this issue?
Answer: Decrease the pantoscopic tilt.
Decreasing the pantoscopic tilt (making the frame front more vertical) will move the bottom edge of the frame away from the patient's cheeks. Increasing face form, widening nose pads, or lengthening temples will not effectively address this specific problem.
In the standard boxing system for frame measurements, what does the 'A' measurement represent?
Answer: The horizontal width of the lens box.
The 'A' measurement, often called the eye size, represents the widest horizontal dimension of the imaginary box drawn around the lens shape. The 'B' measurement is the vertical depth, and the DBL is the distance between lenses.
When fitting a patient for a traditional flat-top (D-seg) bifocal, the segment height is most commonly measured from the bottom edge of the lens to which landmark?
Answer: The lower eyelid margin.
For a standard lined bifocal, the top of the segment line is typically placed at the level of the patient's lower eyelid margin. This positioning allows for clear distance vision when looking straight ahead and easy access to the near segment with a slight downward gaze.
An optician needs to create 2 prism diopters of base-out (BO) prism in a right lens with a power of -4.00 DS. How many millimeters, and in which direction from the patient's PD, must the lens's optical center (OC) be decentered?
Answer: 5 mm temporally
Using Prentice's Rule (Prism = Power x Decentration(cm)), we rearrange to find decentration: Decentration(mm) = (Prism x 10) / Power. Decentration = (2 x 10) / 4 = 5 mm. For a minus lens, the OC is moved in the same direction as the desired base. To achieve base-out, the OC must be moved out, or temporally.
According to the ANSI Z80.1-2020 standard, what is the tolerance for sphere power on a finished single vision lens with a power of -4.50 D?
Answer: ± 0.13 D
The ANSI Z80.1-2020 standard specifies a tolerance of ±0.13 D for sphere powers between +6.50 D and -6.50 D. Since -4.50 D falls within this range, this is the acceptable tolerance.
A patient wearing a new plastic frame complains that it constantly slides down their nose. The optician observes that the bridge of the frame is too wide for the patient. Which of the following is the most appropriate solution?
Answer: Add self-adhesive silicone nose pads.
If a plastic frame's bridge is too wide, it cannot rest securely on the nose, causing it to slide. Adding self-adhesive silicone nose pads is an effective way to narrow the bridge fit, increase friction, and prevent slippage. While adjusting temples can help secure the frame, it doesn't fix the primary issue of a poor bridge fit.