FREE ABO-NOCE ANSI Z80.1 Standards and Tolerances Questions and Answers

Question 1

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?

Accepted Answer

+/- 0.13 D

Answer

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.

Question 2

What is the ANSI Z80.1 tolerance for cylinder axis for a lens with a cylinder power of -1.75 D?

Accepted Answer

+/- 2 degrees

Answer

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.

Question 3

A pair of mounted single vision lenses is inspected. What is the maximum allowable vertical prism imbalance according to ANSI Z80.1 standards?

Accepted Answer

0.33Δ

Answer

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.

Question 4

For a lens with a sphere power of +8.00 D, what is the ANSI Z80.1 tolerance for power?

Accepted Answer

2% of the power

Answer

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.

Question 5

What is the total allowable horizontal prism for a mounted pair of single vision or multifocal lenses?

Accepted Answer

0.67Δ

Answer

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.

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FREE ABO-NOCE ANSI Z80.1 Standards and Tolerances Questions and Answers