ANSI Z80.1 Standards and Tolerances 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 ANSI Z80.1 Standards and Tolerances flashcards as text
ANSI Z80.1 cylinder axis tolerance for prescriptions with cylinder power less than 0.75 D is:
Answer: ±5 degrees
When cylinder power is less than 0.75 D, ANSI Z80.1 allows a wider axis tolerance of ±5 degrees because small cylinder powers are less sensitive to axis error.
According to ANSI Z80.1, progressive addition lenses must have their distance and near reference points verified within what horizontal tolerance of the specified position?
Answer: ±1.0 mm
ANSI Z80.1 specifies that the horizontal position of the distance and near reference points on PALs must be within ±1.0 mm of the specified location.
Which of the following best describes an 'optical center' as used in ANSI Z80.1 verification?
Answer: The point where a ray passes through the lens without deviation
The optical center is the point on a lens through which light passes without being deviated by prism, and it is the basis for MRP placement.
Under ANSI Z80.1, what is the allowable tolerance for prescribed prism when the prescribed amount is greater than 2.00Δ?
Answer: ±0.37Δ or 5% (whichever is greater)
ANSI Z80.1 allows ±0.37Δ or 5% of the prescribed prism amount (whichever is greater) when prescribed prism exceeds 2.00Δ.
ANSI Z80.1 requires that the segment height of a lined bifocal be within what vertical tolerance of the specified height?
Answer: ±1.0 mm
ANSI Z80.1 specifies that lined bifocal segment height must be within ±1.0 mm of the specified height.
Which lens type is NOT subject to the impact-resistance requirements referenced in ANSI Z80.1?
Answer: Safety lenses
Safety lenses are governed by ANSI Z87.1, a separate standard with stricter impact requirements than the dress ophthalmic lens standard Z80.1.
For a PAL with a prescribed add of +2.50 D, the measured add is +2.67 D. According to ANSI Z80.1, this lens:
Answer: Exceeds the ±0.12 D tolerance
The measured add deviates by +0.17 D from the prescribed +2.50 D, which exceeds the ANSI Z80.1 tolerance of ±0.12 D for add power.