NOCE Ophthalmic Products and Materials 3

Question 1

What does the refractive index of a lens material determine?

Accepted Answer

How much the lens bends light relative to its thickness

Answer

The refractive index measures how much a material bends light; a higher index allows a thinner lens to achieve the same optical power.

Question 2

Which frame material is known for its hypoallergenic properties and is most commonly used for patients with metal allergies?

Accepted Answer

Titanium

Answer

Titanium is highly biocompatible and hypoallergenic, making it the preferred metal frame material for patients with nickel or other metal sensitivities.

Question 3

A blue light filtering lens coating is designed to block light primarily in which wavelength range?

Accepted Answer

380–500 nm

Answer

Blue light filtering lenses target the 380–500 nm range (high-energy visible light), which includes the violet and blue wavelengths associated with digital screen exposure.

Question 4

Which type of multifocal lens design eliminates visible segment lines while providing a smooth progression of power?

Accepted Answer

Progressive addition lens

Answer

Progressive addition lenses (PALs) provide a gradual, seamless change in power from distance to near without visible dividing lines.

Question 5

Zyl (cellulose acetate) frame material is best adjusted using which method?

Accepted Answer

Salt pan or hot air heating

Answer

Zyl frames are thermoplastic and must be heated with warm salt or a frame warmer before adjustment to avoid cracking or breaking the material.

NOCE - National Opticianry Competency Examination Practice Test

NOCE - National Opticianry Competency Examination Practice Test

NOCE Ophthalmic Products and Materials 3