Formulas to Know Flashcards
1
Q
Converting minus cyl to plus cyl
A
- add sphere and cylinder
- change sign of the cyl from + to - or vice versa
- add 90 degrees to the axis
(if over 90 subtract 90, if under 90 add 90)
2
Q
Spherical Equivalent
A
- half the cyl and then add it to the sphere
- drop the cyl and axis
-3.00 +1.00 x 180 (+0.50 + -3.00 = -2.50)
-2.50 sph
3
Q
Axial length standard and range
A
23.5 mm
22.0-24.5
4
Q
Anterior Chamber depth standard
A
3.24 mm
5
Q
Lens thickness standard
A
4.63 up to 6.9 mm (as it becomes a cataract)
6
Q
K Readings standard
A
43.0 - 44.0, typically 1D from fellow eye
7
Q
Avg Center Corneal Thickness
A
555 microns
8
Q
Goldman Perimetry age 30-40
A
+1.00
9
Q
Goldman Perimetry age 40-45
A
+1.50
10
Q
Goldman Perimetry age 45-50
A
+2.00
11
Q
Goldman Perimetry age 50-55
A
+2.50
12
Q
Goldman Perimetry age over 55 or cycloplegic
A
+3.00
13
Q
Applanation Principle
A
P=F/A
(pressure equals force over area)
