Formulas Flashcards
1
Q
Estimated Mag (given acuity)
A
Acuity Achieved/Acuity Required
2
Q
Spot Task Acuity Reserve
A
3:1
3
Q
Sustained Task Acuity Reserve
A
2:1
4
Q
Mnom
A
F/4
5
Q
Mmax
A
F/4 + 1
6
Q
Addition
A
1/WD
7
Q
Mag (given WD)
A
Old distance/New distance
8
Q
New Acuity
A
Orignial acuity/Mag
9
Q
New WD required
A
Original WD/Mag required
10
Q
Contrast
A
LB - Lo/LB
11
Q
Relative Size Magnification (RSM)
A
RSM = increased object size/original object size
also
RSM = Acuity achieved/Acuity required
12
Q
Relative Distance Magnification (RDM)
A
RDM = original object distance/new object distance
13
Q
Reference Seeing Distance (RSD)
A
-25cm = -0.25m = q
14
Q
Angular Magnification
A
q - L’/1-dL’
15
Q
Combining different types of mag
A
times together
Total mag = RDM x RSM
