ABO NOCE Basic Opticianry ANSI Z80.1 Standards and Tolerances 5

Question 1

When a lens has a prescribed cylinder of -1.25 D, ANSI Z80.1 requires the cylinder power to be within:

Accepted Answer

±0.12 D

Answer

ANSI Z80.1 specifies a cylinder power tolerance of ±0.12 D for cylinder powers up to ±2.00 D.

Question 2

ANSI Z80.1 defines 'fitting point' on a progressive lens as:

Accepted Answer

The point that aligns with the pupil in primary gaze during fitting

Answer

The fitting point on a PAL is the manufacturer-designated mark that should align with the patient's pupil center in primary gaze during the fitting process.

Question 3

A dispensed pair of single-vision lenses shows 0.60Δ of induced vertical imbalance between the two lenses at the MRP. According to ANSI Z80.1, this is:

Accepted Answer

Unacceptable; vertical tolerance is 0.25Δ per lens

Answer

ANSI Z80.1 limits unwanted vertical prism to 0.25Δ per lens at the MRP, so 0.60Δ of total imbalance far exceeds the per-lens tolerance.

Question 4

Under ANSI Z80.1, what is the purpose of the 'reference point' on a progressive addition lens?

Accepted Answer

To mark where the add power measurement is taken

Answer

The near reference point on a PAL is the designated location where the specified add power is measured and verified.

Question 5

ANSI Z80.1 specifies that the segment of a flat-top bifocal must be within what horizontal tolerance of the specified position?

Accepted Answer

±1.0 mm

Answer

ANSI Z80.1 requires horizontal segment positioning to be within ±1.0 mm of the specified location.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry ANSI Z80.1 Standards and Tolerances 5