ABO OPTICAL EXAM 100% Correct Questions and
Answers (American Board of Opticianry)
What is the radius of curvature of a lens with 1.00D base curve? - ANSWER1.00D=
530mm
What is the radius of curvature of a lens with 6.00D base curve? - ANSWER6.00D x ?
= 530mm
(6.00D/6.00D) x ? = (530mm/6.00D)
?= 88.33
What is the radius of curvature of a lens with 2.00D base curve? - ANSWER2.00D x ?
= 530mm
(2.00D/2.00D) x ? =(530mm/2.00D)
?=265mm
What is the radius of curvature of a lens with 0.50D base curve? - ANSWER0.50D x ?
= 530mm
(0.50D/0.50D) x ? = (530mm/0.50mm)
?= 1060mm
A -2.00D lens has a +4.00D base curve. What is the value of the posterior curve? -
ANSWER4.00D + ? = -2.00D
-4.00D. -4.00D
?= -6.00D
A +3.00D lens has a +7.25D base curve. What is the value of the ocular curve? -
ANSWER7.25D + ? = +3.00D
-7.25D. -7.25D
? = -4.25D
What is the front curve of a +3.00D lens if the back curve is -2.00D? - ANSWER? +(-
2.00D)= 3.00D
+2.00D. +2.00D
? = 5.00D
What is the power of a lens if the front curve is +3.00D and the back curve is -2.00D
at 180° and -1.00D at 90°? - ANSWER3.00 + (-2.00D @ 180)= 1.00D
3.00 + (-1.00D @ 90) = 2.00D
What are the two values on the optical cross?
Rx -3.00 -1.50 x 180 - ANSWER-4.50 @ 90
-3.00 @ 180
What are the two values on the optical cross?
Rx -2.50 +1.00 x 90 - ANSWER-2.50 @ 90
, -1.50 @ 180
What are the two values on the optical cross?
Rx -1.50 +1.50 x 90 - ANSWER-1.50 @ 90
Plano @ 180
What is the power of the near portion?
+1.50 -1.00 x 90 Add +2.00D - ANSWER+1.50D + 2.00D= +3.50 -1.00 × 90
A lens has a power of +2.00D at 90° and +1.00D at 180°. What is the written Rx of
this lens? - ANSWER+2.00 -1.00 x90
+1.00 +1.00 x180
A lens has a power of +3.00D at 180° and -1.00D @90°. What is the Rx? - ANSWER-
1.00 + 4.00 x90
+3.00 - 4.00 x 180
What is the minimum blank size formula? - ANSWERMBS= ED + (2 x decentration per
eye)
What is the MBS?
A= 54mm
DBL= 18mm
ED=58mm
PD=66mm - ANSWERDecentration= 54mm +18mm= 72mm
72mm-66mm= 6mm or 3mm per eye
MBS= 58mm +(2x3mm)
MBS= 64mm
What is the smallest lens blank possible for a 53mm round eyesize frame if each lens
optical center must be decentered 4mm in? - ANSWERDecentration= 4mm
ED=53mm
MBS= 53mm + (2×4mm)
MBS= 61mm
What is the MBS?
A=55mm DBL= 13mm ED= 42mm PD=66mm - ANSWERDecentration= 55mm +
13mm= 68mm
68mm-66mm=2mm or 1mm per eye
MBS=42mm +(2x1mm)
MBS=44mm
A frame with the following measurements has its bifocal segment placed 17mm high
in the eyewire. Measured from the datum line, where will the top of the bifocal be
placed?
A= 55mm
B=46mm
Answers (American Board of Opticianry)
What is the radius of curvature of a lens with 1.00D base curve? - ANSWER1.00D=
530mm
What is the radius of curvature of a lens with 6.00D base curve? - ANSWER6.00D x ?
= 530mm
(6.00D/6.00D) x ? = (530mm/6.00D)
?= 88.33
What is the radius of curvature of a lens with 2.00D base curve? - ANSWER2.00D x ?
= 530mm
(2.00D/2.00D) x ? =(530mm/2.00D)
?=265mm
What is the radius of curvature of a lens with 0.50D base curve? - ANSWER0.50D x ?
= 530mm
(0.50D/0.50D) x ? = (530mm/0.50mm)
?= 1060mm
A -2.00D lens has a +4.00D base curve. What is the value of the posterior curve? -
ANSWER4.00D + ? = -2.00D
-4.00D. -4.00D
?= -6.00D
A +3.00D lens has a +7.25D base curve. What is the value of the ocular curve? -
ANSWER7.25D + ? = +3.00D
-7.25D. -7.25D
? = -4.25D
What is the front curve of a +3.00D lens if the back curve is -2.00D? - ANSWER? +(-
2.00D)= 3.00D
+2.00D. +2.00D
? = 5.00D
What is the power of a lens if the front curve is +3.00D and the back curve is -2.00D
at 180° and -1.00D at 90°? - ANSWER3.00 + (-2.00D @ 180)= 1.00D
3.00 + (-1.00D @ 90) = 2.00D
What are the two values on the optical cross?
Rx -3.00 -1.50 x 180 - ANSWER-4.50 @ 90
-3.00 @ 180
What are the two values on the optical cross?
Rx -2.50 +1.00 x 90 - ANSWER-2.50 @ 90
, -1.50 @ 180
What are the two values on the optical cross?
Rx -1.50 +1.50 x 90 - ANSWER-1.50 @ 90
Plano @ 180
What is the power of the near portion?
+1.50 -1.00 x 90 Add +2.00D - ANSWER+1.50D + 2.00D= +3.50 -1.00 × 90
A lens has a power of +2.00D at 90° and +1.00D at 180°. What is the written Rx of
this lens? - ANSWER+2.00 -1.00 x90
+1.00 +1.00 x180
A lens has a power of +3.00D at 180° and -1.00D @90°. What is the Rx? - ANSWER-
1.00 + 4.00 x90
+3.00 - 4.00 x 180
What is the minimum blank size formula? - ANSWERMBS= ED + (2 x decentration per
eye)
What is the MBS?
A= 54mm
DBL= 18mm
ED=58mm
PD=66mm - ANSWERDecentration= 54mm +18mm= 72mm
72mm-66mm= 6mm or 3mm per eye
MBS= 58mm +(2x3mm)
MBS= 64mm
What is the smallest lens blank possible for a 53mm round eyesize frame if each lens
optical center must be decentered 4mm in? - ANSWERDecentration= 4mm
ED=53mm
MBS= 53mm + (2×4mm)
MBS= 61mm
What is the MBS?
A=55mm DBL= 13mm ED= 42mm PD=66mm - ANSWERDecentration= 55mm +
13mm= 68mm
68mm-66mm=2mm or 1mm per eye
MBS=42mm +(2x1mm)
MBS=44mm
A frame with the following measurements has its bifocal segment placed 17mm high
in the eyewire. Measured from the datum line, where will the top of the bifocal be
placed?
A= 55mm
B=46mm
