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.
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According to ANSI Z80.1 standards, what is the tolerance for sphere power on a 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 0.00 D and +/- 6.50 D. Since +4.50 D falls within this range, this is the applicable tolerance.
What is the ANSI Z80.1 tolerance for cylinder axis for a lens with a cylinder power of -1.75 D?
Answer: +/- 2 degrees
For cylinder powers greater than 1.50 D, the ANSI Z80.1 standard for axis tolerance is +/- 2 degrees. This tighter tolerance is necessary as higher cylinder powers have a greater impact on vision with small axis deviations.
A pair of mounted single vision lenses is inspected. What is the maximum allowable vertical prism imbalance according to ANSI Z80.1 standards?
Answer: 0.33Δ
The tolerance for vertical prism imbalance in a mounted pair of glasses is 0.33Δ (one-third of a prism diopter). This standard helps ensure that the wearer does not experience asthenopia or diplopia from unwanted vertical prism.
For a lens with a sphere power of +8.00 D, what is the ANSI Z80.1 tolerance for power?
Answer: 2% of the power
For sphere powers greater than +/- 6.50 D, the ANSI Z80.1 tolerance is 2% of the specified power. In this case, the tolerance would be 8.00 * 0.02 = +/- 0.16 D.
What is the total allowable horizontal prism for a mounted pair of single vision or multifocal lenses?
Answer: 0.67Δ
The ANSI Z80.1 standard allows for a total horizontal prism of 0.67Δ (two-thirds of a prism diopter) for a pair of mounted lenses. This is the combined prism measured for both eyes.
A lens has a specified base curve of +5.00 D. According to ANSI Z80.1, what is the acceptable range for the measured base curve?
Answer: +4.25 D to +5.75 D
The tolerance for the manufactured front base curve of a lens is +/- 0.75 D from what is specified. Therefore, an acceptable range for a +5.00 D base curve would be from +4.25 D to +5.75 D.
What is the ANSI Z80.1 tolerance for cylinder power on a lens with a cylinder of -2.50 D?
Answer: +/- 0.15 D
For cylinder powers greater than 2.00 D, the ANSI Z80.1 tolerance is +/- 0.15 D. This is slightly more lenient than the tolerance for lower cylinder powers.