W9 Segmented Lenses

Question 1

When laying out a segmented lens for blocking the ___________ is used to correctly position the lens

Answer 1

The segment

Question 2

If the segment is
below the mid-line
of the frame the resulting calculation will be:

Answer 2

A Negative Value

Question 3

If the segment is
moved outward
the resulting calculation will be:

Answer 3

Negative Value

Question 4

If the segment is
above the mid-line
of the frame the resulting calculation will be:

Answer 4

a positive value

Question 5

If the segment is
moved inward
the resulting calculation will be:

Answer 5

Positive value

Question 6

When laying out a flat top segmented lens, if the segment line is straight but the three lensometer spots are not then you have a lens that is

Answer 6

Off Axis

Question 7

The distance between the centers of the right and left segments is equal to the wearer’s

Answer 7

Near PD

Question 8

When measuring the near PD of a segmented lens you should:

Answer 8

measure from the outer edge of one segment to the inner edge of the other segment.

Question 9

If the distance decentration is 4mm and the total inset is 6mm, what is the segment inset?

Answer 9

2mm

Question 10

If the seg inset is 3mm and the inset is 4mm, what is the total (segment) inset?

Answer 10

7mm

Question 11

A flat-top 7x28 is laid out on the centration blocker. The segment is inset by the required amount. Which point on the lens will be used to determine the vertical placement of the segment?

Answer 11

The top of the intermediate segment line

Question 12

Intermediate power in a trifocal is generally:

Answer 12

50% of the add

Question 13

The intersection of the main horizontal and vertical lines on the lens protractor and the centration device denotes the location of the:

Answer 13

boxing center of the frame