Ophthalmic Lenses and Materials Questions and Answers Flashcards
6 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 6 Ophthalmic Lenses and Materials Questions and Answers flashcards as text
What is the Abbe value (V-value) and what does a higher Abbe value indicate?
Answer: A measure of chromatic aberration; higher value means less chromatic aberration
Abbe value measures the dispersion of light through a lens material. Higher Abbe value (less dispersion) = less chromatic aberration = better optical clarity.
Which lens material has the highest impact resistance and is mandated by ANSI Z87.1 for safety eyewear?
Answer: Polycarbonate
Polycarbonate has the highest impact resistance of common lens materials and meets ANSI Z87.1 safety standards. It is mandatory for many occupational and sports applications.
What is the base curve of a lens?
Answer: The reference curve from which other curves are measured
The base curve is the reference curve used to define the lens family. All other curves are measured relative to it.
CR-39 plastic lenses have a refractive index of approximately:
Answer: 1.499
CR-39 (Columbia Resin #39) has a refractive index of approximately 1.498–1.500, making it the standard plastic lens material.
Which lens treatment reduces reflections on the lens surface by applying destructive interference coatings?
Answer: Anti-reflective (AR) coating
Anti-reflective (AR) coatings use thin-film interference to cancel out reflected light, reducing glare and improving light transmission.
Trivex lens material was developed primarily to offer which combination of properties?
Answer: High impact resistance with higher Abbe value than polycarbonate
Trivex (PPG Industries) was designed to match polycarbonate's impact resistance while providing a higher Abbe value (~45) for better optical quality.