ABO Industry Standards Flashcards

Under FDA 21 CFR 801.410, dress ophthalmic lenses must pass the 'drop-ball test' using a steel ball of what diameter?

Answer: 1 inch

The FDA drop-ball test requires that a 1-inch (25.4 mm) diameter steel ball dropped from 50 inches does not fracture the lens.

What is the ANSI Z80.1 tolerance for cylinder axis in lenses with cylinder powers from 0.25D to 0.50D?

Answer: ±7°

For cylinder powers between 0.25D and 0.50D, ANSI Z80.1 permits an axis tolerance of ±7°.

In spectacle dispensing, 'pantoscopic tilt' refers to:

Answer: The vertical angle of the lens plane relative to vertical

Pantoscopic tilt is the vertical angle at which the lower edge of the lens is tilted toward the cheek relative to a vertical plane.

Which of the following lens materials has the highest impact resistance, making it preferred for children's and safety eyewear?

Answer: Polycarbonate

Polycarbonate has the highest impact resistance of all common ophthalmic lens materials, making it the standard for safety and children's eyewear.

When measuring the fitting height for a progressive addition lens, the measurement is taken from:

Answer: The pupil center to the lowest edge of the frame

PAL fitting height is measured from the center of the pupil vertically down to the lowest point of the lens aperture (bottom of the frame).

The 'datum line' of a spectacle frame is defined as:

Answer: The horizontal line dividing the lens aperture into equal upper and lower halves

The datum line is a horizontal line that bisects the lens aperture into two equal halves of the same vertical depth.

According to ANSI Z80.1, what is the maximum allowable decentration for a single vision lens with no prescribed prism?

Answer: The Prentice rule determines if prism is within tolerance

ANSI Z80.1 does not specify a fixed decentration limit; instead, the induced prism at the reference point must fall within the allowable prism tolerance using Prentice's rule.