ABO NOCE Basic Opticianry Spectacle Dispensing Procedures 5

Question 1

A patient receives a prescription of -0.50 – 2.00 x 090. When verifying with the lensometer, the cylinder axis should be confirmed at:

Accepted Answer

090 degrees

Answer

The cylinder axis in the prescription is 090°, and lensometer verification must confirm the cylinder power is oriented at exactly that axis.

Question 2

Prism thinning is a technique used primarily to:

Accepted Answer

Equalize the center thickness of lenses with different powers

Answer

Prism thinning (slab-off or base-up prism) compensates for the differential prismatic effect in anisometropic corrections, but in lens fabrication, 'prism thinning' typically refers to equalizing thickness.

Question 3

When dispensing a frame with a wrap angle greater than 5°, prescriptions above ±2.00 D may require:

Accepted Answer

Compensated lens powers to account for oblique incidence

Answer

High wrap angles cause the lens to be tilted relative to the visual axis, requiring power compensation (tilt-induced sphere and cylinder) to maintain optical accuracy.

Question 4

The effective diameter (ED) of a lens is:

Accepted Answer

The smallest circle that will completely enclose the lens shape

Answer

The effective diameter is the diameter of the smallest circle that entirely encloses the lens shape, used to determine minimum blank size needed.

Question 5

A frame's DBL (distance between lenses) is 20 mm and a patient's bridge width is 14 mm. This frame will likely:

Accepted Answer

Slip down and sit too wide on the face

Answer

A DBL much wider than the patient's bridge width will cause the frame to rest too low and slide down, since the bridge won't be supported by the nose.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Spectacle Dispensing Procedures 5