Spectacle Dispensing and Fitting 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 Spectacle Dispensing and Fitting Questions and Answers flashcards as text
When verifying a finished pair of spectacles with a lensometer, the optician should neutralize the cylinder power by:
Answer: Rotating the lens until the lines are equal in clarity, then reading the power when lines are focused
To find cylinder power, rotate the lens until one set of lines is sharp, read that meridian, then rotate 90° for the other meridian; the difference is the cylinder power.
A patient with a high-plus prescription complains their glasses feel very heavy on the nose. Which recommendation would MOST effectively reduce this problem?
Answer: Use a high-index lens material to reduce center thickness
High-index materials reduce center thickness of plus lenses significantly, directly reducing the lens weight and nose pressure.
The American National Standards Institute (ANSI) Z80.1 standard specifies that the allowable tolerance for sphere power in a finished lens (powers above ±6.50 D) is:
Answer: 2% of the stated power
ANSI Z80.1 allows ±2% of the stated power for lenses with sphere powers greater than ±6.50 D, rather than the fixed tolerance used for lower powers.
When fitting wrap-around frames with a prescription, the optician must compensate for frame wrap angle because it introduces:
Answer: Induced cylinder and sphere power changes
Lens tilt in wrap-around frames induces oblique astigmatism (cylinder) and changes effective sphere power, requiring compensated lens powers.
A patient whose frame sits too low on the nose (segment too high for bifocal) should have the nose pads adjusted by:
Answer: Moving the nose pads farther apart (widening) to raise the frame
Widening (spreading) nose pads moves the pads lower on the nose, which raises the frame and thus raises the segment position.
In spectacle dispensing, the term 'seg drop' refers to:
Answer: The vertical distance the segment is dropped below the distance optical center
Seg drop is the vertical distance between the distance optical center and the top of the bifocal segment, measured downward.
A patient with a -6.00 D prescription selects a frame with a 54 mm eye size. If the patient's PD is 60 mm and the frame PD is 68 mm, what is the induced prism at the optical center if the lenses are not decentered?
Answer: 2.4 prism diopters base-out per eye
Using Prentice's Rule: P = cF = 0.4 cm × 6.00 D = 2.4 prism diopters base-out per eye (4 mm decentration outward in a minus lens = base-out prism).