NOCE Ophthalmic Products and Materials 5

Question 1

Which frame material is the MOST flexible and corrosion-resistant, commonly used in rimless and semi-rimless mountings?

Accepted Answer

Titanium

Answer

Titanium is extremely lightweight, highly corrosion-resistant, and strong enough for drill-mounted rimless frames that require durable thin mounting points.

Question 2

A patient asks about the difference between a gradient tint and a solid tint. The key difference is:

Accepted Answer

Gradient tints transition from darker at the top to lighter at the bottom

Answer

A gradient tint fades from a darker concentration at the top of the lens (blocking overhead glare) to a lighter or clear area at the bottom (for reading or near tasks).

Question 3

When comparing CR-39 to high-index 1.74 material, which statement is MOST accurate?

Accepted Answer

High-index 1.74 produces thinner lenses but has more chromatic aberration

Answer

High-index 1.74 produces thinner, lighter lenses for strong prescriptions but has a lower Abbe value (around 33) compared to CR-39 (Abbe ~58), meaning more chromatic aberration.

Question 4

Which ANSI standard specifies the minimum impact resistance requirements for dress eyewear sold in the United States?

Accepted Answer

ANSI Z80.1

Answer

ANSI Z80.1 covers requirements for prescription ophthalmic lenses including the drop-ball impact test that all dress eyewear lenses must pass before dispensing.

Question 5

A patient's AR-coated lenses show a persistent greenish or purplish residual reflection. This is MOST likely due to:

Accepted Answer

The normal residual reflection color of AR coating design

Answer

AR coatings are designed with a specific residual reflection color (often green or blue-violet) that results from the interference properties of the thin-film coating stack — this is normal and intentional.

NOCE - National Opticianry Competency Examination Practice Test

NOCE - National Opticianry Competency Examination Practice Test

NOCE Ophthalmic Products and Materials 5