ABO NOCE Basic Opticianry General Practice 3

Question 1

Compared to CR-39 (index 1.50), a lens with a refractive index of 1.67 will be:

Accepted Answer

Thinner and lighter for the same prescription

Answer

Higher refractive index materials bend light more efficiently, allowing lenses to be made thinner for the same prescription power.

Question 2

The distance from the back surface of the spectacle lens to the front of the cornea is called the:

Accepted Answer

Vertex distance

Answer

Vertex distance is clinically important for high prescriptions (typically ±4.00 D and above) because changes affect effective power.

Question 3

Which multifocal lens type has no visible dividing line between distance and near zones?

Accepted Answer

Progressive addition lens

Answer

Progressive addition lenses provide a gradual power transition without a visible segment line.

Question 4

A patient is prescribed base-in prism. The perceived image will be displaced toward:

Accepted Answer

The apex (temporally)

Answer

Light bends toward the base of a prism, but the perceived image is always displaced toward the apex.

Question 5

Anti-reflective coatings reduce reflections using the principle of:

Accepted Answer

Destructive interference

Answer

AR coatings use thin film layers whose reflected waves are out of phase and cancel each other through destructive interference.

ABO NOCE Basic Opticianry Practice Test