ABO EXAM PRE-TEST
100+ (2026 A+ Graded) Exam-Style Questions | Verified Solutions |
Complete Answer Key
100% Guarantee Pass
📋 DOCUMENT OVERVIEW 100 Qs
This document, "ABO EXAM PRE-TEST," covers various topics in optometry and eye care, including lens
measurement, optics, refraction, and lens manufacturing. It provides 100 multiple-choice questions with
correct answers and detailed explanations, allowing students to review and understand complex concepts
in a comprehensive manner. By utilizing this document, students can efficiently study and review key topics,
solidifying their knowledge and preparing them for exams.
✓ Verified Answers ✓ Exam Ready ✓ Study Guide
Trusted by thousands of students and professionals worldwide
EXAM QUESTIONS
QUESTION 1
When ordering a six inch temple, its corresponding millimeter value is which of the following?
A. 135 mm
B. 140 mm
C. 145 mm
D. 150 mm
CORRECT ANSWER
150 mm
RATIONALE: To convert inches to millimeters, we need to multiply the number of inches by 25.4, as there are 25.4
millimeters in one inch. This calculation is necessary because the question is asking for the equivalent value in millimeters
for a six-inch measurement, requiring a conversion between the two units of measurement.
Trusted by thousands of students and professionals worldwide Page 1 of 38
, QUESTION 2
What is the focal length of a 2 diopter lens?
A. 500 cm
B. 39.37 inches
C. 500 mm
D. 2 meters
CORRECT ANSWER
500 mm
RATIONALE: A 2 diopter lens is defined as a lens that converges light rays from infinity to a point 50 cm (0.5 meters or 500
mm) in front of the lens. By understanding the diopter definition, you can calculate the focal length of a 2 diopter lens,
which is 0.5 meters or 500 mm.
QUESTION 3
Wavelengths are measured in
A. Meters
B. Decimeters
C. Centimeters
D. Nanometers
CORRECT ANSWER
Nanometers
RATIONALE: Wavelengths of light, which are the distances between consecutive peaks or troughs, are incredibly small and
fall within the realm of atomic and subatomic scales, making a unit of measurement with a much smaller magnitude
necessary to accurately express these values. Nanometers, which represent one billionth of a meter, provide a suitable unit
of measurement for expressing the wavelengths of light, given their extremely small size.
QUESTION 4
Which of the following has the shortest and therefore most harmful wavelength?
A. UVC
B. UVB
C. UVA
D. INFRARED
CORRECT ANSWER
UVC
RATIONALE: UVC radiation has the shortest wavelength among the given options because as wavelength decreases, energy
increases, and this trend is observed in the ultraviolet spectrum where UVC has the lowest wavelength, making its energy
the highest. This high energy is the reason UVC is considered the most harmful, as it has enough energy to cause
significant damage to DNA.
Trusted by thousands of students and professionals worldwide Page 2 of 38
, QUESTION 5
When two light wavesw are in "in phase" they will
A. Destroy on another
B. Reduce each front by half
C. Compound one another
D. None of the above
CORRECT ANSWER
Compound one another
RATIONALE: When two light waves are in phase, their peaks and troughs align perfectly, resulting in an amplification of the
combined wave. This amplification occurs because the crests of one wave overlap with the crests of the other, creating a
more pronounced waveform.
QUESTION 6
The cylinder axis tolerance for a 1.00D cylinder according to ANSI Z80.1 is
A. Plus or minus 7 degrees
B. Plus or minus 5 degrees
C. Plus or minus 3 degrees
D. Plus or minus 2 degrees
CORRECT ANSWER
Plus or minus 3 degrees
RATIONALE: The tolerance for a 1.00D cylinder axis is determined by a formula that takes into account the cylinder
diameter, and the resulting value is then rounded to the nearest 5 degrees, which in this case results in a tolerance of plus
or minus 3 degrees. This is due to the specific rounding process outlined in ANSI Z80.1, which ensures a consistent and
standardized approach to axis tolerance across various ophthalmic lenses.
QUESTION 7
A plus lens decentered "out" will result in a finished lens which is
A. Balanced
B. Thicker temporally
C. Thicker nasally
D. Uniform in edge thickness
CORRECT ANSWER
Thicker temporally
RATIONALE: Decentering a plus lens out means moving the center of the lens away from the optical axis, towards the
nasal side. As a result, more of the lens material is displaced towards the nasal side, causing the finished lens to be thicker
nasally, but because of the convex shape of the lens, more material is also pushed forward towards the temporal side.
Trusted by thousands of students and professionals worldwide Page 3 of 38
, QUESTION 8
A minus lens decentered "out" will result in a finished lens which is
A. Balanced
B. Thicker temporally
C. Thicker nasally
D. Uniform in edge thickness
CORRECT ANSWER
Thicker nasally
RATIONALE: When a minus lens is decentered "out," the center of the lens remains thicker temporally, but the edge of the
lens will be thicker nasally due to the additional thickness of the lens material being spread outwards from the center. This
results in a lens that is thicker on the nasal side near the edge.
QUESTION 9
An uncoated normal plastic lens will reflect approximately ______% of light.
A. 2%
B. 4%
C. 8%
D. 12%
CORRECT ANSWER
8%
RATIONALE: The correct answer is due to the Fresnel reflection, a phenomenon where light reflects off a surface, resulting
in a significant percentage of light being reflected regardless of the surface's material properties. In the case of an
uncoated normal plastic lens, approximately 8% of light is reflected due to the Fresnel reflection, which outweighs the small
difference in refractive indices between air and plastic.
QUESTION 10
A lens having a minus curve on both front and back is called
A. Toric
B. Meniscus
C. Biconvex
D. Biconcave
CORRECT ANSWER
Biconcave
RATIONALE: A biconcave lens has a curved surface that is inwardly concave on both the front and back sides. This type of
lens is characterized by a minus curve on both sides, which is a distinguishing feature that makes it biconcave.
Trusted by thousands of students and professionals worldwide Page 4 of 38
100+ (2026 A+ Graded) Exam-Style Questions | Verified Solutions |
Complete Answer Key
100% Guarantee Pass
📋 DOCUMENT OVERVIEW 100 Qs
This document, "ABO EXAM PRE-TEST," covers various topics in optometry and eye care, including lens
measurement, optics, refraction, and lens manufacturing. It provides 100 multiple-choice questions with
correct answers and detailed explanations, allowing students to review and understand complex concepts
in a comprehensive manner. By utilizing this document, students can efficiently study and review key topics,
solidifying their knowledge and preparing them for exams.
✓ Verified Answers ✓ Exam Ready ✓ Study Guide
Trusted by thousands of students and professionals worldwide
EXAM QUESTIONS
QUESTION 1
When ordering a six inch temple, its corresponding millimeter value is which of the following?
A. 135 mm
B. 140 mm
C. 145 mm
D. 150 mm
CORRECT ANSWER
150 mm
RATIONALE: To convert inches to millimeters, we need to multiply the number of inches by 25.4, as there are 25.4
millimeters in one inch. This calculation is necessary because the question is asking for the equivalent value in millimeters
for a six-inch measurement, requiring a conversion between the two units of measurement.
Trusted by thousands of students and professionals worldwide Page 1 of 38
, QUESTION 2
What is the focal length of a 2 diopter lens?
A. 500 cm
B. 39.37 inches
C. 500 mm
D. 2 meters
CORRECT ANSWER
500 mm
RATIONALE: A 2 diopter lens is defined as a lens that converges light rays from infinity to a point 50 cm (0.5 meters or 500
mm) in front of the lens. By understanding the diopter definition, you can calculate the focal length of a 2 diopter lens,
which is 0.5 meters or 500 mm.
QUESTION 3
Wavelengths are measured in
A. Meters
B. Decimeters
C. Centimeters
D. Nanometers
CORRECT ANSWER
Nanometers
RATIONALE: Wavelengths of light, which are the distances between consecutive peaks or troughs, are incredibly small and
fall within the realm of atomic and subatomic scales, making a unit of measurement with a much smaller magnitude
necessary to accurately express these values. Nanometers, which represent one billionth of a meter, provide a suitable unit
of measurement for expressing the wavelengths of light, given their extremely small size.
QUESTION 4
Which of the following has the shortest and therefore most harmful wavelength?
A. UVC
B. UVB
C. UVA
D. INFRARED
CORRECT ANSWER
UVC
RATIONALE: UVC radiation has the shortest wavelength among the given options because as wavelength decreases, energy
increases, and this trend is observed in the ultraviolet spectrum where UVC has the lowest wavelength, making its energy
the highest. This high energy is the reason UVC is considered the most harmful, as it has enough energy to cause
significant damage to DNA.
Trusted by thousands of students and professionals worldwide Page 2 of 38
, QUESTION 5
When two light wavesw are in "in phase" they will
A. Destroy on another
B. Reduce each front by half
C. Compound one another
D. None of the above
CORRECT ANSWER
Compound one another
RATIONALE: When two light waves are in phase, their peaks and troughs align perfectly, resulting in an amplification of the
combined wave. This amplification occurs because the crests of one wave overlap with the crests of the other, creating a
more pronounced waveform.
QUESTION 6
The cylinder axis tolerance for a 1.00D cylinder according to ANSI Z80.1 is
A. Plus or minus 7 degrees
B. Plus or minus 5 degrees
C. Plus or minus 3 degrees
D. Plus or minus 2 degrees
CORRECT ANSWER
Plus or minus 3 degrees
RATIONALE: The tolerance for a 1.00D cylinder axis is determined by a formula that takes into account the cylinder
diameter, and the resulting value is then rounded to the nearest 5 degrees, which in this case results in a tolerance of plus
or minus 3 degrees. This is due to the specific rounding process outlined in ANSI Z80.1, which ensures a consistent and
standardized approach to axis tolerance across various ophthalmic lenses.
QUESTION 7
A plus lens decentered "out" will result in a finished lens which is
A. Balanced
B. Thicker temporally
C. Thicker nasally
D. Uniform in edge thickness
CORRECT ANSWER
Thicker temporally
RATIONALE: Decentering a plus lens out means moving the center of the lens away from the optical axis, towards the
nasal side. As a result, more of the lens material is displaced towards the nasal side, causing the finished lens to be thicker
nasally, but because of the convex shape of the lens, more material is also pushed forward towards the temporal side.
Trusted by thousands of students and professionals worldwide Page 3 of 38
, QUESTION 8
A minus lens decentered "out" will result in a finished lens which is
A. Balanced
B. Thicker temporally
C. Thicker nasally
D. Uniform in edge thickness
CORRECT ANSWER
Thicker nasally
RATIONALE: When a minus lens is decentered "out," the center of the lens remains thicker temporally, but the edge of the
lens will be thicker nasally due to the additional thickness of the lens material being spread outwards from the center. This
results in a lens that is thicker on the nasal side near the edge.
QUESTION 9
An uncoated normal plastic lens will reflect approximately ______% of light.
A. 2%
B. 4%
C. 8%
D. 12%
CORRECT ANSWER
8%
RATIONALE: The correct answer is due to the Fresnel reflection, a phenomenon where light reflects off a surface, resulting
in a significant percentage of light being reflected regardless of the surface's material properties. In the case of an
uncoated normal plastic lens, approximately 8% of light is reflected due to the Fresnel reflection, which outweighs the small
difference in refractive indices between air and plastic.
QUESTION 10
A lens having a minus curve on both front and back is called
A. Toric
B. Meniscus
C. Biconvex
D. Biconcave
CORRECT ANSWER
Biconcave
RATIONALE: A biconcave lens has a curved surface that is inwardly concave on both the front and back sides. This type of
lens is characterized by a minus curve on both sides, which is a distinguishing feature that makes it biconcave.
Trusted by thousands of students and professionals worldwide Page 4 of 38
