Given the following prescription:
-2.00 +1.25 x 35
What is the axis meridian with the highest power?
a)35
b)125
The answer is A)
as long as highest = the most power.
Absolute value from zero.
Usually when describing power at certain axis the word Effective is used.
The Effective Power at the 035th meridian is -2.00
The Effective Power at the 125th meridian is -0.75
Try this...
Transposition
1.Algebraically add the sphere and cylinder:
_____ + _____ = _____
2. Change the sign of the cylinder:
_____ -/+ _____
3.Change the axis 90 degrees:
_____ _____ X ± 090
Final axis must be between
0 and 180
If it is NOT, then
If you added 90 subtract instead
If you subtracted 90 Add instead
Example:
+2.00 +1.00 X 180
1.Algebraically add the sphere and cylinder:
+2.00 + +1.00 = + 3.00
2. Change the sign of the cylinder:
+3.00 -1.00
3.Change the axis 90 degrees:
+3.00 -1.00 X 090
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