ABO NOCE Basic Opticianry ANSI Z80.1 Standards and Tolerances 4

Question 1

ANSI Z80.1 cylinder axis tolerance for prescriptions with cylinder power less than 0.75 D is:

Accepted Answer

±5 degrees

Answer

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.

Question 2

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?

Accepted Answer

±1.0 mm

Answer

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.

Question 3

Which of the following best describes an 'optical center' as used in ANSI Z80.1 verification?

Accepted Answer

The point where a ray passes through the lens without deviation

Answer

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.

Question 4

Under ANSI Z80.1, what is the allowable tolerance for prescribed prism when the prescribed amount is greater than 2.00Δ?

Accepted Answer

±0.37Δ or 5% (whichever is greater)

Answer

ANSI Z80.1 allows ±0.37Δ or 5% of the prescribed prism amount (whichever is greater) when prescribed prism exceeds 2.00Δ.

Question 5

ANSI Z80.1 requires that the segment height of a lined bifocal be within what vertical tolerance of the specified height?

Accepted Answer

±1.0 mm

Answer

ANSI Z80.1 specifies that lined bifocal segment height must be within ±1.0 mm of the specified height.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry ANSI Z80.1 Standards and Tolerances 4