ABO NOCE Basic Opticianry Spectacle Dispensing Procedures 4

Question 1

Vertex distance is the measurement from the:

Accepted Answer

Back surface of the lens to the corneal apex

Answer

Vertex distance is measured from the back vertex of the lens to the front surface of the cornea (corneal apex), typically 12–14 mm.

Question 2

Which adjustment corrects a frame where one lens sits higher than the other when the patient wears it?

Accepted Answer

Adjust the nose pad heights unequally to level the frame

Answer

Uneven nose pad heights can compensate for facial asymmetry or unequal ear heights, leveling the frame in front of the patient's eyes.

Question 3

For a prescription with +5.00 D sphere, changing vertex distance from 12 mm to 14 mm will effectively:

Accepted Answer

Reduce the effective plus power reaching the eye

Answer

Moving a plus lens farther from the eye reduces its effective power at the corneal plane, so a longer vertex distance weakens the effective plus power.

Question 4

The minimum fitting height for a standard progressive lens is typically:

Accepted Answer

18 mm

Answer

Most standard progressive lenses require a minimum fitting height of approximately 18 mm to accommodate the full progression corridor.

Question 5

When a patient's bifocal segment top appears to float in and out of vision, the most likely cause is:

Accepted Answer

Segment height set too low

Answer

If the segment top is positioned too low, the patient must tilt their head or look down excessively, making the segment difficult to use consistently.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Spectacle Dispensing Procedures 4