ABO ADVANCED OPHTHALMIC
DISPENSING COMPREHENSIVE EXAM
QUESTIONS AND ANSWERS 100%
VERIFIED. JUST RELEASED
1. A patient experiences a vertical imbalance of 2.00 prism diopters at a reading level of
10mm. If the right lens power in the vertical meridian is +4.00 D, what is the power of the left
lens in the vertical meridian?
A. +6.00 D
B. +2.00 D
C. +1.00 D
D. +8.00 D
Answer: B
Conceptual Explanation: Using Prentice’s Rule (P = c * F), the difference in power must be
2.00 D to create a 2.00 prism diopter imbalance at 1cm (10mm). If the right is +4.00, the
left must be +2.00 or +6.00. Standard clinical practice for vertical imbalance assumes the
difference causes the dip; +2.00 D creates the 2 prism diopter difference.
2. Which lens design utilizes a ‘flattening’ effect toward the periphery to reduce marginal
astigmatism and distortion?
A. Biconvex lens
,B. Planar lens
C. Meniscus lens
D. Aspheric lens
Answer: D
Conceptual Explanation: Aspheric lenses are designed with a non-spherical surface that
flattens toward the edges to correct aberrations such as marginal astigmatism and
distortion, especially in high-power prescriptions.
3. A lens has a front surface power of +8.00 D and a back surface power of -4.00 D. If the lens
is moved 5mm closer to the eye, what happens to its effective power?
A. It becomes more plus
B. It remains the same
C. It becomes more minus
D. It increases in cylinder only
Answer: C
Conceptual Explanation: When a plus lens is moved closer to the eye, its effective power
decreases (becomes more minus or less plus). When moved further away, it becomes more
plus.
, 4. Which of the following describes the condition where the two eyes have significantly
different refractive errors, often exceeding 2.00 D?
A. Antimetropia
B. Aphakia
C. Amblyopia
D. Anisometropia
Answer: D
Conceptual Explanation: Anisometropia is the condition in which the two eyes have
unequal refractive power. This often leads to vertical imbalance issues in multifocals.
5. What is the result of increasing the index of refraction of a lens material while keeping the
curves constant?
A. The focal length increases
B. Chromatic aberration disappears
C. The lens power decreases
D. The lens power increases
Answer: D
Conceptual Explanation: According to the lensmaker’s formula, power is proportional to
(n-1). Increasing the index (n) increases the refractive power of the surfaces.
DISPENSING COMPREHENSIVE EXAM
QUESTIONS AND ANSWERS 100%
VERIFIED. JUST RELEASED
1. A patient experiences a vertical imbalance of 2.00 prism diopters at a reading level of
10mm. If the right lens power in the vertical meridian is +4.00 D, what is the power of the left
lens in the vertical meridian?
A. +6.00 D
B. +2.00 D
C. +1.00 D
D. +8.00 D
Answer: B
Conceptual Explanation: Using Prentice’s Rule (P = c * F), the difference in power must be
2.00 D to create a 2.00 prism diopter imbalance at 1cm (10mm). If the right is +4.00, the
left must be +2.00 or +6.00. Standard clinical practice for vertical imbalance assumes the
difference causes the dip; +2.00 D creates the 2 prism diopter difference.
2. Which lens design utilizes a ‘flattening’ effect toward the periphery to reduce marginal
astigmatism and distortion?
A. Biconvex lens
,B. Planar lens
C. Meniscus lens
D. Aspheric lens
Answer: D
Conceptual Explanation: Aspheric lenses are designed with a non-spherical surface that
flattens toward the edges to correct aberrations such as marginal astigmatism and
distortion, especially in high-power prescriptions.
3. A lens has a front surface power of +8.00 D and a back surface power of -4.00 D. If the lens
is moved 5mm closer to the eye, what happens to its effective power?
A. It becomes more plus
B. It remains the same
C. It becomes more minus
D. It increases in cylinder only
Answer: C
Conceptual Explanation: When a plus lens is moved closer to the eye, its effective power
decreases (becomes more minus or less plus). When moved further away, it becomes more
plus.
, 4. Which of the following describes the condition where the two eyes have significantly
different refractive errors, often exceeding 2.00 D?
A. Antimetropia
B. Aphakia
C. Amblyopia
D. Anisometropia
Answer: D
Conceptual Explanation: Anisometropia is the condition in which the two eyes have
unequal refractive power. This often leads to vertical imbalance issues in multifocals.
5. What is the result of increasing the index of refraction of a lens material while keeping the
curves constant?
A. The focal length increases
B. Chromatic aberration disappears
C. The lens power decreases
D. The lens power increases
Answer: D
Conceptual Explanation: According to the lensmaker’s formula, power is proportional to
(n-1). Increasing the index (n) increases the refractive power of the surfaces.
