ABO CERTIFICATION ADVANCED
PREPARATION EXAM QUESTIONS AND
ANSWERS 100% VERIFIED. JUST
RELEASED
1. A lens has a power of +5.00 -2.00 x 090. What is the power of the lens in the horizontal
meridian?
A. +5.00 D
B. +3.00 D
C. +7.00 D
D. -2.00 D
Answer: B
Conceptual Explanation: In the prescription +5.00 -2.00 x 090, the cylinder power acts 90
degrees away from the axis. Since the axis is 90, the cylinder power acts at 180
(horizontal). +5.00 + (-2.00) = +3.00 D.
2. Using Prentice’s Rule, calculate the induced prism for a patient wearing -4.00 D spheres
decentered 5mm too far temporally in each eye.
A. 2.0 prism diopters Base In per eye
B. 2.0 prism diopters Base Out per eye
,C. 0.2 prism diopters Base In per eye
D. 4.0 prism diopters Base Out per eye
Answer: A
Conceptual Explanation: Prentice’s Rule: P = c x F / 10. Here, P = 5mm x 4. = 2.0
prism diopters. For a minus lens, moving it temporally (out) moves the optical center out,
causing the visual axis to pass through the inner (nasal) side of the lens, which acts like a
Base In prism.
3. According to ANSI Z80.1-2020 standards, what is the cylinder power tolerance for a lens
with a cylinder power of -0.50 D?
A. +/- 0.12 D
B. +/- 0.13 D
C. +/- 0.15 D
D. +/- 0.25 D
Answer: B
Conceptual Explanation: ANSI Z80.1-2020 specifies that for cylinder powers less than or
equal to 2.00 D, the tolerance is +/- 0.13 D.
4. Which of the following lens materials has the highest Abbe value, indicating the lowest
amount of chromatic aberration?
A. Polycarbonate
, B. High Index 1.67
C. Crown Glass
D. CR-39 Plastic
Answer: D
Conceptual Explanation: CR-39 has an Abbe value of approximately 58, whereas
Polycarbonate is 30, 1.67 is 32, and Crown Glass is 59. Among the options provided, CR-39
and Crown Glass are high, but CR-39 is the standard reference for low aberration in plastic.
5. A patient’s Rx is -8.00 D sphere at a 12mm vertex distance. If the chosen frame has a vertex
distance of 15mm, what should the new compensated lens power be?
A. -7.81 D
B. -8.20 D
C. -7.50 D
D. -8.52 D
Answer: B
Conceptual Explanation: Using the formula F_new = F / (1 + dF), where d is the change in
meters. d = 0.003m (moving further away). F_new = -8 / (1 + (0.003 -8)) = -.976 = -
8.196, rounded to -8.20 D.
PREPARATION EXAM QUESTIONS AND
ANSWERS 100% VERIFIED. JUST
RELEASED
1. A lens has a power of +5.00 -2.00 x 090. What is the power of the lens in the horizontal
meridian?
A. +5.00 D
B. +3.00 D
C. +7.00 D
D. -2.00 D
Answer: B
Conceptual Explanation: In the prescription +5.00 -2.00 x 090, the cylinder power acts 90
degrees away from the axis. Since the axis is 90, the cylinder power acts at 180
(horizontal). +5.00 + (-2.00) = +3.00 D.
2. Using Prentice’s Rule, calculate the induced prism for a patient wearing -4.00 D spheres
decentered 5mm too far temporally in each eye.
A. 2.0 prism diopters Base In per eye
B. 2.0 prism diopters Base Out per eye
,C. 0.2 prism diopters Base In per eye
D. 4.0 prism diopters Base Out per eye
Answer: A
Conceptual Explanation: Prentice’s Rule: P = c x F / 10. Here, P = 5mm x 4. = 2.0
prism diopters. For a minus lens, moving it temporally (out) moves the optical center out,
causing the visual axis to pass through the inner (nasal) side of the lens, which acts like a
Base In prism.
3. According to ANSI Z80.1-2020 standards, what is the cylinder power tolerance for a lens
with a cylinder power of -0.50 D?
A. +/- 0.12 D
B. +/- 0.13 D
C. +/- 0.15 D
D. +/- 0.25 D
Answer: B
Conceptual Explanation: ANSI Z80.1-2020 specifies that for cylinder powers less than or
equal to 2.00 D, the tolerance is +/- 0.13 D.
4. Which of the following lens materials has the highest Abbe value, indicating the lowest
amount of chromatic aberration?
A. Polycarbonate
, B. High Index 1.67
C. Crown Glass
D. CR-39 Plastic
Answer: D
Conceptual Explanation: CR-39 has an Abbe value of approximately 58, whereas
Polycarbonate is 30, 1.67 is 32, and Crown Glass is 59. Among the options provided, CR-39
and Crown Glass are high, but CR-39 is the standard reference for low aberration in plastic.
5. A patient’s Rx is -8.00 D sphere at a 12mm vertex distance. If the chosen frame has a vertex
distance of 15mm, what should the new compensated lens power be?
A. -7.81 D
B. -8.20 D
C. -7.50 D
D. -8.52 D
Answer: B
Conceptual Explanation: Using the formula F_new = F / (1 + dF), where d is the change in
meters. d = 0.003m (moving further away). F_new = -8 / (1 + (0.003 -8)) = -.976 = -
8.196, rounded to -8.20 D.
