Page 1 of 148
(CDOS) Certified Diagnostic Ophthalmic
Sonographer EXAM 1 WITH COMPLETE 350 QUESTIONS
AND CORRECT DETAILED SOLUTIONS LATEST THIS
YEAR
CDOS exam: 170 MCQs covering ocular anatomy, ultrasound physics, instrumentation, scanning
techniques, and interpretation. This set is designed to reflect the breadth and depth of the
official content domains. Below you will find 250 randomized multiple-choice
questions without any subtopics or sections. Each question includes the correct answer and a
succinct, italicized rationale.
Question 1
A 78-year-old patient with dense cataracts presents for evaluation of posterior segment
pathology. What is the primary advantage of using B-scan ultrasonography over clinical
examination alone?
A. It provides higher resolution of the anterior chamber.
B. It eliminates the need for patient cooperation.
C. It can accurately image intraocular structures when direct visualization is impossible.
D. It is faster than fundus photography.
Answer: C
B-scan ultrasound is most useful when direct visualization of intraocular structures is difficult or
impossible due to media opacities.
, Page 2 of 148
Question 2
A patient is referred for assessment of a dome-shaped choroidal lesion. On A-scan, the internal
reflectivity of a typical choroidal melanoma is most accurately described as:
A. Extremely high (>90%).
B. Low to moderate (30–60%).
C. Extremely low (<5%).
D. Uniformly high throughout the lesion.
Answer: B
Ocular malignant melanomas have a low-to-moderate reflectivity pattern (30–60%) on A-scan
because their densely packed cells produce relatively few internal acoustic interfaces.
Question 3
During a B-scan examination, you observe a highly reflective structure that produces multiple
parallel echoes behind it, each spaced equally apart. This artifact is best described as:
A. Comet-tail artifact.
B. Ring-down artifact.
C. Reverberation artifact.
D. Mirror-image artifact.
, Page 3 of 148
Answer: C
Reverberation occurs when sound bounces back and forth between two highly reflective
surfaces, producing equally spaced false echoes deeper in the image.
Question 4
A 65-year-old patient presents for cataract surgery biometry. Which ultrasound frequency is
most commonly used for A-scan biometry of the adult eye?
A. 2 MHz
B. 5 MHz
C. 10 MHz
D. 20 MHz
Answer: C
For ophthalmic A-scan biometry, a frequency of 10 MHz is standard because it provides a good
balance between penetration and axial resolution.
Question 5
Which layer of the eye contains the choroidal vasculature that supplies the outer retina?
A. Sclera
B. Iris
, Page 4 of 148
C. Uvea
D. Retina
Answer: C
The uvea comprises the iris, ciliary body, and choroid; the choroid provides the main blood
supply to the outer retina.
Question 6
What is the average axial length of a normal adult human eye?
A. 16 mm
B. 22 mm
C. 24 mm
D. 28 mm
Answer: C
The normal adult axial length ranges from 22–24 mm, with 24 mm frequently cited as the
average.
Question 7
In ultrasound physics, the primary function of the piezoelectric crystals within the transducer is
to:
(CDOS) Certified Diagnostic Ophthalmic
Sonographer EXAM 1 WITH COMPLETE 350 QUESTIONS
AND CORRECT DETAILED SOLUTIONS LATEST THIS
YEAR
CDOS exam: 170 MCQs covering ocular anatomy, ultrasound physics, instrumentation, scanning
techniques, and interpretation. This set is designed to reflect the breadth and depth of the
official content domains. Below you will find 250 randomized multiple-choice
questions without any subtopics or sections. Each question includes the correct answer and a
succinct, italicized rationale.
Question 1
A 78-year-old patient with dense cataracts presents for evaluation of posterior segment
pathology. What is the primary advantage of using B-scan ultrasonography over clinical
examination alone?
A. It provides higher resolution of the anterior chamber.
B. It eliminates the need for patient cooperation.
C. It can accurately image intraocular structures when direct visualization is impossible.
D. It is faster than fundus photography.
Answer: C
B-scan ultrasound is most useful when direct visualization of intraocular structures is difficult or
impossible due to media opacities.
, Page 2 of 148
Question 2
A patient is referred for assessment of a dome-shaped choroidal lesion. On A-scan, the internal
reflectivity of a typical choroidal melanoma is most accurately described as:
A. Extremely high (>90%).
B. Low to moderate (30–60%).
C. Extremely low (<5%).
D. Uniformly high throughout the lesion.
Answer: B
Ocular malignant melanomas have a low-to-moderate reflectivity pattern (30–60%) on A-scan
because their densely packed cells produce relatively few internal acoustic interfaces.
Question 3
During a B-scan examination, you observe a highly reflective structure that produces multiple
parallel echoes behind it, each spaced equally apart. This artifact is best described as:
A. Comet-tail artifact.
B. Ring-down artifact.
C. Reverberation artifact.
D. Mirror-image artifact.
, Page 3 of 148
Answer: C
Reverberation occurs when sound bounces back and forth between two highly reflective
surfaces, producing equally spaced false echoes deeper in the image.
Question 4
A 65-year-old patient presents for cataract surgery biometry. Which ultrasound frequency is
most commonly used for A-scan biometry of the adult eye?
A. 2 MHz
B. 5 MHz
C. 10 MHz
D. 20 MHz
Answer: C
For ophthalmic A-scan biometry, a frequency of 10 MHz is standard because it provides a good
balance between penetration and axial resolution.
Question 5
Which layer of the eye contains the choroidal vasculature that supplies the outer retina?
A. Sclera
B. Iris
, Page 4 of 148
C. Uvea
D. Retina
Answer: C
The uvea comprises the iris, ciliary body, and choroid; the choroid provides the main blood
supply to the outer retina.
Question 6
What is the average axial length of a normal adult human eye?
A. 16 mm
B. 22 mm
C. 24 mm
D. 28 mm
Answer: C
The normal adult axial length ranges from 22–24 mm, with 24 mm frequently cited as the
average.
Question 7
In ultrasound physics, the primary function of the piezoelectric crystals within the transducer is
to:
