ABO NOCE Basic Opticianry Lens Coatings and Treatments 4

Question 1

A patient reports that their anti-reflective coated lenses look smudged almost immediately after cleaning. What is the most likely cause?

Accepted Answer

The patient is using a silicone-based cleaner incompatible with AR coating

Answer

Silicone-based or alcohol-based cleaners can break down the hydrophobic top coat on AR lenses, making them attract oils and smear more easily.

Question 2

Which property of a photochromic lens determines how dark it becomes in sunlight?

Accepted Answer

The concentration and type of photochromic molecules embedded in the lens

Answer

The darkening depth of photochromic lenses depends on the density and chemical nature of the silver halide or organic photochromic molecules within the lens.

Question 3

A scratch-resistant coating is best described as:

Accepted Answer

A hard surface treatment that reduces but does not eliminate lens scratching

Answer

Scratch-resistant coatings increase surface hardness to reduce scratching but cannot make a lens completely impervious to abrasion.

Question 4

What is the primary purpose of a hydrophobic (water-repellent) top coat applied over an AR coating?

Accepted Answer

To make the lens surface easier to clean by causing water to bead and roll off

Answer

Hydrophobic top coats reduce the surface energy of the lens so water beads up and rolls off rather than spreading, keeping the lens cleaner.

Question 5

When dispensing AR-coated lenses to a patient who works in a kitchen, which additional coating property is most important to recommend?

Accepted Answer

Oleophobic (oil-repellent) properties

Answer

Kitchen workers are frequently exposed to cooking oils and grease, making an oleophobic coating critical to maintaining lens cleanliness.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Lens Coatings and Treatments 4