Measurements

Question 1

Frame measurements include:

Answer 1

A
B
DBL
Longest Radius

Question 2

Lens measurements include:

Answer 2

Base Curve
Center thickness
Edge thickness
Diameter

Question 3

Measurements are used to calculate what 2 things?

Answer 3

Effective diameter ED

Frame PR or DBC

Question 4

Measurements needed from the ordering dispensary include:

Answer 4

PD: DPD, NPD

Fitting height or Seg height

Question 5

Single vision lens require:

Answer 5

DPD or NPD

PRP height

Question 6

Boxing method image

Answer 6

Question 7

“A”

Answer 7

Horizontal width

Question 8

Datum line

Answer 8

B/2

Question 9

DBL

Answer 9

Distance between lenses

Question 10

LR

Answer 10

longest radius

Question 11

GCD, DBC, Frame PD

Answer 11

Geometric Center Distance
Distance Between Centers
Frame PD

A+DBL

Question 12

Segment height

Answer 12

Question 13

Segment drop

Answer 13

(B/2) - seg height)

Question 14

“C”

Answer 14

Horizontal width of a lens at the datum

Question 15

Frame tracer

Answer 15

Traces frame

Question 16

Lens blank measurements tools include:

Answer 16

Lens caliper
Geneva lens measure (lens clock)
PD stick - mm ruler

Question 17

Lens calipers

Answer 17

Measure the thickness of a lens

Question 18

What 2 thicknesses that are measured on the lens?

Answer 18

Center thickness and Edge thickness

Question 19

What unit of measurement is used for measuring thickness of a lens?

Answer 19

mm

Question 20

What unit of measurement is used when using a lens clock ?

Answer 20

Diopters

Convex side (+)
Concave side (-) - sometimes in red

Question 21

What is the BC formula?

Answer 21

F1+F2=Ftotal

Ftotal-F1=F2
Rx power-BC=Back Power Curve

Question 22

Is it more accurate to use a lens clock or sagometer?

Answer 22

Sagometer

Question 23

What unit does a sagometer measure in?

Answer 23

Radians (rads)

Question 24

Millimeter ruler

Answer 24

PD stick