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
When a lens has a prescribed cylinder of -1.25 D, ANSI Z80.1 requires the cylinder power to be within:
Answer: ±0.12 D
ANSI Z80.1 specifies a cylinder power tolerance of ±0.12 D for cylinder powers up to ±2.00 D.
ANSI Z80.1 defines 'fitting point' on a progressive lens as:
Answer: The point that aligns with the pupil in primary gaze during fitting
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.
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:
Answer: Unacceptable; vertical tolerance is 0.25Δ per lens
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.
Under ANSI Z80.1, what is the purpose of the 'reference point' on a progressive addition lens?
Answer: To mark where the add power measurement is taken
The near reference point on a PAL is the designated location where the specified add power is measured and verified.
ANSI Z80.1 specifies that the segment of a flat-top bifocal must be within what horizontal tolerance of the specified position?
Answer: ±1.0 mm
ANSI Z80.1 requires horizontal segment positioning to be within ±1.0 mm of the specified location.
When verifying prescribed prism of 1.50Δ base in, ANSI Z80.1 allows a tolerance of:
Answer: ±0.25Δ
For prescribed prism of 2.00Δ or less, ANSI Z80.1 allows a tolerance of ±0.25Δ in any meridian.
Which of the following would ANSI Z80.1 classify as a cosmetic defect requiring rejection of a finished lens?
Answer: Multiple scratches within the central 30 mm optical zone visible under diffuse illumination
ANSI Z80.1 surface quality requirements reject lenses with multiple defects such as scratches or bubbles within the central optical zone that are visible under diffuse light.