Dispensing

Question 1

What other supplemental GOS3 vouchers can a px get?

Answer 1

Tint, prism (not plano), complex (10 or more), small glasses/special face

Question 2

What are the focimetry tolerances?

Answer 2

Dioptres= 0.25
Centres= 1mm
Cyls: <=0.50 is 9; <=0.75 is 6, <=1.50 is 4, >1.50 is 3

Question 3

How much is prism thinning on varifocals normally?

Answer 3

2/3rd of ADD BD

Question 4

How do you calculate rx change for BVD change?

Answer 4

F=F/1-dF
if the lens is moved away then d is negative, if the lens is moved closer d is a positive value

Question 5

How to calculate prismatic effect with units?

Answer 5

P= cF
P is prismatic power, c is decentration in cmm, F is power in D

Question 6

How to calculate differential prism depending on base direction?

Answer 6

Horizontal: same is add, opposite is subtract
Vertical: same is subtract, opposite is add

Question 7

How to calculate power at 90 or 180 when the cyl and power cross is at different axis?

Answer 7

F90 = Sph + (Cyl x cos^2(axis))
F180 = Sph + (Cyl x sin^2(axis))

Question 8

How to calculate MSU

Answer 8

MSU= effective diameter + (2 x decentration (monocular difference between frame pd and px pd)) + wastage (2mm)

Question 9

How to increase movement of an RGP?

Answer 9

-Increase BOZR
-Decrease BOZD
-Decrease TD

Question 10

How to decrease movement of an RGP?

Answer 10

-Decrease BOZR
-Increase BOZD
-Increase TD

Question 11

How to maintain fitting relationship of RGP when changing BOZR and BOZD?

Answer 11

Increasing BOZD by 0.5mm will require increase (flattening) of BOZR by 0.05mm

Decrease in BOZD by 0.5mm will require decrease (steepening) of BOZR by 0.05mm

Question 12

How does BVP and BOZR for RGP relate?

Answer 12

0.05mm is 0.25D
FAP- flatten add positive
SAM- steep add minus

Question 13

What is the formula for magnification?

Answer 13

Mag= F/4