ABO/NCLE Opticianry Certification Exam 2026: Comprehensive
Professional Practice Test — Optical Principles, Lens Dispensing,
Spectacle Fitting, Contact Lenses, Ocular Anatomy & Patient Care
— 190 Multiple-Choice Questions with Answers & Detailed
Rationales
1. A patient's prescription reads: OD -2.00 -1.00 x 090. What is the correct transposition of
this prescription?
A. -3.00 +1.00 x 180
B. -2.00 +1.00 x 090
C. -3.00 +1.00 x 090
D. -2.00 -1.00 x 180
Correct Answer: A
Explanation: To transpose, add the sphere and cylinder (-2.00 + -1.00 = -3.00), change the
cylinder's sign (+1.00), and change the axis by 90 degrees (090 + 90 = 180).
2. Which of the following lens materials has the highest Abbe value, indicating the least
amount of chromatic aberration?
A. Polycarbonate
B. Trivex
C. CR-39
D. High-Index 1.74
Correct Answer: C
Explanation: CR-39 (hard resin) has an Abbe value of 58, which is significantly higher than
polycarbonate (30) or high-index materials, providing superior optical clarity.
3. A patient complains of a "jack-in-the-box" effect when looking away from the center of
their new progressive addition lenses. This is most likely caused by:
,A. An incorrect pupillary distance measurement.
B. Unwanted cylinder in the reading zone.
C. High base curve misalignment.
D. The design of the progressive corridor and peripheral distortion zones.
Correct Answer: D
Explanation: The "jack-in-the-box" phenomenon is a common adaptation issue with PALs,
caused by the swim effect and distortion in the lens's periphery as the eye moves through
different power zones.
4. When performing a manual lensometer reading, the three thin lines in the target are
known as the:
A. Sphere lines.
B. Cylinder lines.
C. Axis lines.
D. Prism lines.
Correct Answer: B
Explanation: In a manual lensometer, the three thin, parallel lines are the cylinder lines, used
to determine the axis and cylinder power of the lens.
5. A patient with a -10.00 D spectacle prescription is interested in contact lenses. Which of
the following contact lens powers would be most appropriate, assuming a vertex distance of
12mm?
A. -10.00 D
B. -9.00 D
C. -8.50 D
D. -11.00 D
Correct Answer: C
Explanation: For high minus prescriptions, the contact lens power is less minus than the
spectacle power due to the elimination of vertex distance. The effective power is calculated
using the formula Fc = Fs / (1 - d*Fs).
,6. The primary purpose of a slab-off prism in a spectacle lens is to:
A. Correct for aniselkonia.
B. Balance the vertical prismatic effects at the reading level for anisometropic prescriptions.
C. Increase the thickness of the lens for cosmetic reasons.
D. Reduce chromatic aberration in high-power lenses.
Correct Answer: B
Explanation: A slab-off is a bicentric grind that creates a line of demarcation, inducing base-
up prism in the more minus lens to equalize the vertical prism imbalance at the near point.
7. Which of the following is NOT a characteristic of a hydrophobic contact lens material?
A. It repels water and deposits.
B. It is highly wettable.
C. It is often used in silicone hydrogel lenses.
D. It allows for high oxygen permeability.
Correct Answer: B
Explanation: Hydrophobic materials repel water, making them inherently less wettable. They
require surface treatments or internal wetting agents to be comfortable for contact lens
wear.
8. A presbyopic patient has a spectacle Rx of +2.00 -0.50 x 180. Their add power is +2.25.
What is the reading power in the vertical meridian?
A. +4.25
B. +3.75
C. +4.00
D. +2.00
Correct Answer: A
, Explanation: The reading power is the sum of the sphere and the add power: +2.00 + (+2.25)
= +4.25 D. The cylinder power remains the same but is not added to the sphere for this
calculation.
9. The optical center of a lens is the point where:
A. The lens is thinnest.
B. The prismatic effect is zero.
C. The cylinder power is greatest.
D. The lens provides the best cosmesis.
Correct Answer: B
Explanation: By definition, the optical center of a lens is the point through which light passes
without being deviated, meaning there is no prismatic effect at this point.
10. A patient returns with their new glasses complaining that the floor appears to curve
upwards. This is a classic symptom of:
A. An incorrect axis.
B. An incorrect pupillary distance.
C. Base-up prism.
D. Base-down prism.
Correct Answer: C
Explanation: Base-up prism creates a "curved floor" or "walking on a hill" sensation because
it displaces the image downward, forcing the patient to look up to see the floor.
11. Which of the following is the correct formula for calculating the sagittal depth of a lens?
A. s = r - √(r² - (d/2)²)
B. s = r² / (2d)
C. s = (d/2)² / (2r)
D. s = r + √(r² - (d/2)²)
Correct Answer: A
Professional Practice Test — Optical Principles, Lens Dispensing,
Spectacle Fitting, Contact Lenses, Ocular Anatomy & Patient Care
— 190 Multiple-Choice Questions with Answers & Detailed
Rationales
1. A patient's prescription reads: OD -2.00 -1.00 x 090. What is the correct transposition of
this prescription?
A. -3.00 +1.00 x 180
B. -2.00 +1.00 x 090
C. -3.00 +1.00 x 090
D. -2.00 -1.00 x 180
Correct Answer: A
Explanation: To transpose, add the sphere and cylinder (-2.00 + -1.00 = -3.00), change the
cylinder's sign (+1.00), and change the axis by 90 degrees (090 + 90 = 180).
2. Which of the following lens materials has the highest Abbe value, indicating the least
amount of chromatic aberration?
A. Polycarbonate
B. Trivex
C. CR-39
D. High-Index 1.74
Correct Answer: C
Explanation: CR-39 (hard resin) has an Abbe value of 58, which is significantly higher than
polycarbonate (30) or high-index materials, providing superior optical clarity.
3. A patient complains of a "jack-in-the-box" effect when looking away from the center of
their new progressive addition lenses. This is most likely caused by:
,A. An incorrect pupillary distance measurement.
B. Unwanted cylinder in the reading zone.
C. High base curve misalignment.
D. The design of the progressive corridor and peripheral distortion zones.
Correct Answer: D
Explanation: The "jack-in-the-box" phenomenon is a common adaptation issue with PALs,
caused by the swim effect and distortion in the lens's periphery as the eye moves through
different power zones.
4. When performing a manual lensometer reading, the three thin lines in the target are
known as the:
A. Sphere lines.
B. Cylinder lines.
C. Axis lines.
D. Prism lines.
Correct Answer: B
Explanation: In a manual lensometer, the three thin, parallel lines are the cylinder lines, used
to determine the axis and cylinder power of the lens.
5. A patient with a -10.00 D spectacle prescription is interested in contact lenses. Which of
the following contact lens powers would be most appropriate, assuming a vertex distance of
12mm?
A. -10.00 D
B. -9.00 D
C. -8.50 D
D. -11.00 D
Correct Answer: C
Explanation: For high minus prescriptions, the contact lens power is less minus than the
spectacle power due to the elimination of vertex distance. The effective power is calculated
using the formula Fc = Fs / (1 - d*Fs).
,6. The primary purpose of a slab-off prism in a spectacle lens is to:
A. Correct for aniselkonia.
B. Balance the vertical prismatic effects at the reading level for anisometropic prescriptions.
C. Increase the thickness of the lens for cosmetic reasons.
D. Reduce chromatic aberration in high-power lenses.
Correct Answer: B
Explanation: A slab-off is a bicentric grind that creates a line of demarcation, inducing base-
up prism in the more minus lens to equalize the vertical prism imbalance at the near point.
7. Which of the following is NOT a characteristic of a hydrophobic contact lens material?
A. It repels water and deposits.
B. It is highly wettable.
C. It is often used in silicone hydrogel lenses.
D. It allows for high oxygen permeability.
Correct Answer: B
Explanation: Hydrophobic materials repel water, making them inherently less wettable. They
require surface treatments or internal wetting agents to be comfortable for contact lens
wear.
8. A presbyopic patient has a spectacle Rx of +2.00 -0.50 x 180. Their add power is +2.25.
What is the reading power in the vertical meridian?
A. +4.25
B. +3.75
C. +4.00
D. +2.00
Correct Answer: A
, Explanation: The reading power is the sum of the sphere and the add power: +2.00 + (+2.25)
= +4.25 D. The cylinder power remains the same but is not added to the sphere for this
calculation.
9. The optical center of a lens is the point where:
A. The lens is thinnest.
B. The prismatic effect is zero.
C. The cylinder power is greatest.
D. The lens provides the best cosmesis.
Correct Answer: B
Explanation: By definition, the optical center of a lens is the point through which light passes
without being deviated, meaning there is no prismatic effect at this point.
10. A patient returns with their new glasses complaining that the floor appears to curve
upwards. This is a classic symptom of:
A. An incorrect axis.
B. An incorrect pupillary distance.
C. Base-up prism.
D. Base-down prism.
Correct Answer: C
Explanation: Base-up prism creates a "curved floor" or "walking on a hill" sensation because
it displaces the image downward, forcing the patient to look up to see the floor.
11. Which of the following is the correct formula for calculating the sagittal depth of a lens?
A. s = r - √(r² - (d/2)²)
B. s = r² / (2d)
C. s = (d/2)² / (2r)
D. s = r + √(r² - (d/2)²)
Correct Answer: A
