ABO NOCE Basic Opticianry Spectacle Lens Aberrations 3

Question 1

Lateral chromatic aberration in spectacle lenses causes which visual symptom for the wearer?

Accepted Answer

Color fringing at the edges of objects viewed peripherally

Answer

Lateral chromatic aberration disperses colors at different lateral positions off-axis, causing colored fringes around objects viewed through the lens periphery.

Question 2

The Abbe value (V-number) of a lens material directly affects which type of aberration?

Accepted Answer

Chromatic aberration

Answer

The Abbe value measures a material's dispersion; lower Abbe values indicate greater chromatic aberration in the finished lens.

Question 3

A patient complains of colored halos around lights when looking through the edge of their new high-index lenses. The most likely cause is:

Accepted Answer

Low Abbe value of the high-index material

Answer

High-index materials typically have lower Abbe values, producing more chromatic aberration and colored fringes, especially in the lens periphery.

Question 4

Which of the following lens materials has the HIGHEST Abbe value (least chromatic aberration)?

Accepted Answer

CR-39 plastic (Abbe ~58)

Answer

CR-39 plastic has an Abbe value of approximately 58, giving it the least chromatic aberration among common spectacle lens materials.

Question 5

When comparing transverse (lateral) and longitudinal chromatic aberration, which statement is correct?

Accepted Answer

Transverse CA causes color fringing; longitudinal CA causes axial blur

Answer

Transverse (lateral) chromatic aberration displaces colors sideways causing fringing, while longitudinal CA separates colors along the optical axis causing axial blur.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Spectacle Lens Aberrations 3