ABO ADVANCED OPHTHALMIC OPTICS
FINAL EXAM STUDY GUIDE
QUESTIONS AND ANSWERS 100%
VERIFIED. JUST RELEASED
1. A lens has a prescription of -4.00 -1.00 x 180. What is the power of the lens in the 90-
degree meridian?
A. -4.00 D
B. -4.50 D
C. -3.00 D
D. -5.00 D
Answer: D
Conceptual Explanation: In minus cylinder form, the sphere power (-4.00) is at the axis
(180). The combined power (sphere + cylinder) of -5.00 is 90 degrees away from the axis,
which is the 90-degree meridian.
2. Which material has the lowest Abbe value, indicating the highest amount of chromatic
aberration?
A. Crown Glass
B. CR-39
,C. Polycarbonate
D. Trivex
Answer: C
Conceptual Explanation: Polycarbonate has an Abbe value of approximately 30, which is
lower than Crown Glass (59), CR-39 (58), and Trivex (45). Lower Abbe values result in
higher chromatic aberration.
3. Using Prentice’s Rule, calculate the induced prism for a +5.00 D lens decentered 4mm
inwards.
A. 2.0 prism diopters Base-In
B. 2.0 prism diopters Base-Out
C. 0.2 prism diopters Base-In
D. 2.5 prism diopters Base-Out
Answer: A
Conceptual Explanation: Prentice’s Rule: P = (Power * Decentration in cm). P = 5.00 * 0.4
= 2.0 prism diopters. For a plus lens, decentering inward (toward the nose) creates Base-In
prism.
4. According to ANSI Z80.1 standards, what is the tolerance for a cylinder power ranging
between 0.00D and 2.00D?
A. +/- 0.12 D
, B. +/- 0.06 D
C. +/- 0.25 D
D. +/- 0.13 D
Answer: D
Conceptual Explanation: ANSI Z80.1-2015 specifies a cylinder power tolerance of +/-
0.13 D for cylinder powers up to 2.00 D.
5. A patient’s Rx is -10.00 D sphere at a vertex distance of 14mm. If the new frame sits at
10mm, what is the effective power required in the new lens?
A. -9.62 D
B. -11.00 D
C. -10.42 D
D. -10.00 D
Answer: C
Conceptual Explanation: Using F_new = F / (1 - dF), where d is the change in meters
(0.004m closer). For minus lenses, moving closer makes them feel weaker, so you need
more minus: -10 / (1 - (-0.004 -10)) = -.96 = -10.42 D.
6. In the ‘Boxing System’, the ‘B’ measurement refers to:
A. The horizontal width of the lens
B. The vertical height of the lens
FINAL EXAM STUDY GUIDE
QUESTIONS AND ANSWERS 100%
VERIFIED. JUST RELEASED
1. A lens has a prescription of -4.00 -1.00 x 180. What is the power of the lens in the 90-
degree meridian?
A. -4.00 D
B. -4.50 D
C. -3.00 D
D. -5.00 D
Answer: D
Conceptual Explanation: In minus cylinder form, the sphere power (-4.00) is at the axis
(180). The combined power (sphere + cylinder) of -5.00 is 90 degrees away from the axis,
which is the 90-degree meridian.
2. Which material has the lowest Abbe value, indicating the highest amount of chromatic
aberration?
A. Crown Glass
B. CR-39
,C. Polycarbonate
D. Trivex
Answer: C
Conceptual Explanation: Polycarbonate has an Abbe value of approximately 30, which is
lower than Crown Glass (59), CR-39 (58), and Trivex (45). Lower Abbe values result in
higher chromatic aberration.
3. Using Prentice’s Rule, calculate the induced prism for a +5.00 D lens decentered 4mm
inwards.
A. 2.0 prism diopters Base-In
B. 2.0 prism diopters Base-Out
C. 0.2 prism diopters Base-In
D. 2.5 prism diopters Base-Out
Answer: A
Conceptual Explanation: Prentice’s Rule: P = (Power * Decentration in cm). P = 5.00 * 0.4
= 2.0 prism diopters. For a plus lens, decentering inward (toward the nose) creates Base-In
prism.
4. According to ANSI Z80.1 standards, what is the tolerance for a cylinder power ranging
between 0.00D and 2.00D?
A. +/- 0.12 D
, B. +/- 0.06 D
C. +/- 0.25 D
D. +/- 0.13 D
Answer: D
Conceptual Explanation: ANSI Z80.1-2015 specifies a cylinder power tolerance of +/-
0.13 D for cylinder powers up to 2.00 D.
5. A patient’s Rx is -10.00 D sphere at a vertex distance of 14mm. If the new frame sits at
10mm, what is the effective power required in the new lens?
A. -9.62 D
B. -11.00 D
C. -10.42 D
D. -10.00 D
Answer: C
Conceptual Explanation: Using F_new = F / (1 - dF), where d is the change in meters
(0.004m closer). For minus lenses, moving closer makes them feel weaker, so you need
more minus: -10 / (1 - (-0.004 -10)) = -.96 = -10.42 D.
6. In the ‘Boxing System’, the ‘B’ measurement refers to:
A. The horizontal width of the lens
B. The vertical height of the lens
