ABO NOCE Basic Opticianry Ophthalmic Products and Materials Questions and Answers 2

Question 1

Which lens material has the highest Abbe value among commonly used ophthalmic lens materials?

Accepted Answer

Crown glass

Answer

Crown glass (ophthalmic crown) has the highest Abbe value of approximately 58, meaning it produces the least chromatic aberration.

Question 2

What is the primary purpose of an anti-reflective (AR) coating on ophthalmic lenses?

Accepted Answer

Reduce glare and increase light transmission

Answer

AR coatings reduce surface reflections, increasing light transmission through the lens and reducing glare for the wearer.

Question 3

A patient requires a photochromic lens. Which factor does NOT significantly affect the darkening speed of photochromic lenses?

Accepted Answer

Patient's prescription power

Answer

The prescription power of the lens does not significantly affect photochromic darkening speed; temperature, UV intensity, and lens material all do.

Question 4

Which type of lens coating should be applied LAST during the coating process?

Accepted Answer

Anti-reflective coat

Answer

The anti-reflective coating is applied as the final top coat because it must be deposited over all other coatings to function correctly.

Question 5

What is the refractive index of standard CR-39 plastic lens material?

Accepted Answer

1.50

Answer

CR-39 (allyl diglycol carbonate) has a refractive index of 1.50, making it the baseline for standard plastic ophthalmic lenses.

ABO NOCE Basic Opticianry Practice Test