Math Flashcards
1
Q
What is the formula for calculating dK?
A
dK value = (d ・K )/t
d - diffusion co-efficient (breathability)
K - Solubility co-efficient (water content)
t - thickness (sometimes written as L)
2
Q
The Diameter of a GP lens is 10.2, what is the size of the optic zone
A
Optic Zone = Total Diameter - Diameter of secondary curves - diameter of peripheral curves
OZ = 10.2 - (2 ・0.3) - (2・0.3)
OZ = 9.0 (you subtract the diameter off BOTH SIDES
3
Q
How do you convert Diopters to mm of Radius
A
mm of radius = 337.5 / diopters
r = (n-1)/D r = BC in mm D = BC in Diopters n = n of the tear film (1.3375)
