Originally Posted by
azhanli22
Hello folks!
I'm currently studying for the Advanced Test and I want to make sure I have a clear understanding of two different concepts (correct me if I'm wrong please!):
Effective power is what the patient experiences as the power of the lens while wearing them. Adding vertex distance increase plus power and removing vertex distance decreases plus power (or increases minus power).
Compensated Rx then is knowing that the effective power will be different than what is actually prescribed, and is made so that if a patient is wearing a pair of glasses at a specified vertex distance, provides the same refractive power as to what is prescribed.
So if a patient was prescribed a -10.00 lens OD with a refractive vertex distance of 10mm but selected a frame with a vertex distance of 15mm then:
The effective power would be less than -10.00 because there is an increase in vertex distance (more plus power).
And the compensated Rx would be more than -10.00 to compensate for the increase in plus power.
Does this sound about right?
Thanks in advance!
Bookmarks