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

Question 1

Photochromic lenses darken when exposed to UV light because they contain:

Accepted Answer

Silver halide crystals (glass) or organic photochromic molecules (plastic) that undergo a reversible chemical reaction when exposed to UV

Answer

Glass photochromics use silver halide crystals; plastic photochromics (like Transitions) use organic naphthopyran molecules. Both undergo a reversible photochemical reaction that causes darkening when UV-exposed.

Question 2

Polarized lenses reduce glare primarily by:

Accepted Answer

Absorbing horizontally polarized light reflected from flat surfaces such as water, roads, and snow

Answer

Reflected glare from flat horizontal surfaces is predominantly horizontally polarized. Polarized lenses have vertically oriented transmission axes that absorb this horizontal light.

Question 3

Which characteristic of a sunglass lens is described by the term 'luminous transmittance'?

Accepted Answer

The percentage of visible light that passes through the lens

Answer

Luminous transmittance is the ratio of the luminous flux transmitted through a lens to the incident luminous flux — essentially what percentage of visible light passes through.

Question 4

A patient asks about the difference between standard single vision and aspheric lens designs. The key advantage of aspheric lenses is:

Accepted Answer

Reduced lens thickness, weight, and peripheral aberrations compared to spherical designs

Answer

Aspheric lenses use a varying surface curvature (not a perfect sphere) to reduce lens thickness and weight while controlling peripheral optical aberrations, particularly for plus lenses.

Question 5

Blue light blocking lenses have become popular. Which part of the visible spectrum do they primarily filter?

Accepted Answer

The high-energy visible (HEV) blue-violet light range, approximately 380–450 nm

Answer

Blue light blocking lenses filter high-energy visible (HEV) blue-violet light in the approximately 380–450 nm range, which is thought to contribute to digital eye strain and may affect circadian rhythms.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

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