21 - Progressive Lenses

Question 1

What are some things that could cause issues to progressives wearers? 6

Answer 1

-Monocular PDs being wrong (1 right/1wrong etc)
-Binocular PD rather than Monocular
-Fitting cross measured for 1 eye only not both.
-being forced into it
-too high expectations
-incorrect fitting - tilt etc

Question 2

What affects the distortion in a progressive lens? 4

Answer 2

-The add power
-Rate of progressive power change
-Intermdiate zone width
-Zone widths

Question 3

Characteristics for hard design progressives? 3

Answer 3

-Larger and more specific areas of unwarying power for distance and near
-quick change in power at distortion
-smaller intermediate area

Question 4

Characteristics for soft design progressives? 3

Answer 4

-slower vertical change in power as the wearer goes from distance to near
-change in power at distortion is more gradual
-distance is more affected compared to near, intermediate wider

Question 5

What happens if progressives dont have prism thinning? 2

Answer 5

Increased thickness especially in plus or low minus
Prism thinning thins the bottom edge

Question 6

Progressive lenses in plus or low minus power ranges will be thicker than a flat-top multifocal lens of equal power T/F

Answer 6

True

Question 7

What happens to the lower portion of the lens as the plus power is introduced?

Answer 7

The surface curvature steepens.

Question 8

To keep the lower lens edge from becoming too thin, the whole lens must be thickened. T/F

Answer 8

True