(ABOS) Exam ACTUAL EXAM COMPLETE
QUESTIONS AND CORRECT ANSWERS LATEST
UPDATE THIS YEAR (2026/2027)!
Single Vision - ANSWERcorrects for one distance
Multifocal - ANSWERCorrects with two or more
prescriptions (or 'powers')
Bifocal - ANSWERlens having two focus strengths
Trifocal - ANSWERpertaining to having three focus
strengths
,Calculating Prismatic Effects - ANSWERobtained at the
center of an optical lens by producing a difference in edge
thickness, either by grinding the back surface at an angle
to the front surface during lens surfacing or, if the lens has
sufficient power, de-centering the optical center of the lens
Compounding Prism - ANSWERBI & BI
BO & BO
BU & BD
Cancelling Prism - ANSWERBI & BO
BD & BD
BU & BU
, Prentice's Rule - ANSWERP=hcm x D
P=amount of prism created
h= number of cm OC moved
cm= centimeters (convert to mm, divide by 10)
D= power in meridian with error
Vertical Imbalance - ANSWERThe difference in vertical
prism power at the reading level in a pair of lenses.
OC Height's by lens - ANSWERSV = 1/2 of B
Progressive = Fitting cross
FT = 5mm above segment