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Practice questions for this set
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BI & BI
BO & BO
BU & BD
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1 Single Vision 2 Vertical Centration
3 Calculating Prismatic Effects 4 Compounding Prism
Don't know?
, Single Vision corrects for one distance
Multifocal Corrects with two or more prescriptions (or 'powers')
Bifocal lens having two focus strengths
Trifocal pertaining to having three focus strengths
obtained at the center of an optical lens by producing
a difference in edge thickness, either by grinding the
Calculating Prismatic
back surface at an angle to the front surface during
Effects
lens surfacing or, if the lens has sufficient power, de-
centering the optical center of the lens
BI & BI
Compounding Prism BO & BO
BU & BD
BI & BO
Cancelling Prism BD & BD
BU & BU
P=hcm x D
P=amount of prism created
Prentice's Rule h= number of cm OC moved
cm= centimeters (convert to mm, divide by 10)
D= power in meridian with error
The difference in vertical prism power at the reading
Vertical Imbalance
level in a pair of lenses.
SV = 1/2 of B
OC Height's by lens Progressive = Fitting cross
FT = 5mm above segment
A plus lens when moved farther from the eye gains in
Vertex Compensation plus power
Distance is 0 with CL because they are on the eye