Page 1 of 123
CDOS CERTIFIED DIAGNOSTIC OPHTHALMIC
SONOGRAPHER PRACTICE EXAM LATEST ALL 200
QUESTIONS WITH CORRECT SOLUTIONS AND
RATIONALES JUST RELEASED
1. The piezoelectric crystals in an ophthalmic transducer most directly convert:
• A) Electrical energy into magnetic fields
• B) Mechanical vibration into electrical signals
• C) Electrical energy into mechanical vibration
• D) Light energy into sound waves
Answer: C
The piezoelectric effect causes crystals to deform (vibrate) when an electric voltage is applied,
generating ultrasound waves (transmit mode). The reverse process creates electrical signals
from returning echoes (receive mode) .
2. Which physical property of an ultrasound wave directly determines axial resolution?
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• A) Frequency
• B) Amplitude
• C) Velocity
• D) Wavelength
Answer: A
Higher frequency waves have shorter wavelengths, which improves axial resolution because the
system can distinguish structures that are closer together along the beam's axis .
3. The average axial length of an adult human eye is closest to:
• A) 16 mm
• B) 22 mm
• C) 24 mm
• D) 28 mm
Answer: C
Normal adult axial length ranges from 22–24 mm, with 24 mm often cited as the average .
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4. Which condition is characterized by accumulation of drusen, macular pigment changes, and
subretinal hemorrhage?
• A) Diabetic retinopathy
• B) Age-related macular degeneration (AMD)
• C) Retinal vein occlusion
• D) Central serous retinopathy
Answer: B
AMD presents with drusen, pigmentary changes, and potentially subretinal hemorrhage,
particularly in the wet (neovascular) form .
5. What acoustic phenomenon primarily causes the "shadowing" artifact seen behind a dense
cataract on B-scan?
• A) Reflection
• B) Refraction
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• C) Absorption
• D) Scattering
Answer: C
Dense cataracts absorb a large portion of the ultrasound energy, preventing it from reaching
structures behind the lens, resulting in a shadow .
6. In B-scan ultrasonography, which gain control primarily affects the brightness of structures
near the transducer?
• A) Total gain
• B) Near-gain
• C) Far-gain
• D) Dynamic range
Answer: B
Near-gain adjusts amplification of echoes from shallow (near) tissues, influencing their
brightness .
CDOS CERTIFIED DIAGNOSTIC OPHTHALMIC
SONOGRAPHER PRACTICE EXAM LATEST ALL 200
QUESTIONS WITH CORRECT SOLUTIONS AND
RATIONALES JUST RELEASED
1. The piezoelectric crystals in an ophthalmic transducer most directly convert:
• A) Electrical energy into magnetic fields
• B) Mechanical vibration into electrical signals
• C) Electrical energy into mechanical vibration
• D) Light energy into sound waves
Answer: C
The piezoelectric effect causes crystals to deform (vibrate) when an electric voltage is applied,
generating ultrasound waves (transmit mode). The reverse process creates electrical signals
from returning echoes (receive mode) .
2. Which physical property of an ultrasound wave directly determines axial resolution?
, Page 2 of 123
• A) Frequency
• B) Amplitude
• C) Velocity
• D) Wavelength
Answer: A
Higher frequency waves have shorter wavelengths, which improves axial resolution because the
system can distinguish structures that are closer together along the beam's axis .
3. The average axial length of an adult human eye is closest to:
• A) 16 mm
• B) 22 mm
• C) 24 mm
• D) 28 mm
Answer: C
Normal adult axial length ranges from 22–24 mm, with 24 mm often cited as the average .
, Page 3 of 123
4. Which condition is characterized by accumulation of drusen, macular pigment changes, and
subretinal hemorrhage?
• A) Diabetic retinopathy
• B) Age-related macular degeneration (AMD)
• C) Retinal vein occlusion
• D) Central serous retinopathy
Answer: B
AMD presents with drusen, pigmentary changes, and potentially subretinal hemorrhage,
particularly in the wet (neovascular) form .
5. What acoustic phenomenon primarily causes the "shadowing" artifact seen behind a dense
cataract on B-scan?
• A) Reflection
• B) Refraction
, Page 4 of 123
• C) Absorption
• D) Scattering
Answer: C
Dense cataracts absorb a large portion of the ultrasound energy, preventing it from reaching
structures behind the lens, resulting in a shadow .
6. In B-scan ultrasonography, which gain control primarily affects the brightness of structures
near the transducer?
• A) Total gain
• B) Near-gain
• C) Far-gain
• D) Dynamic range
Answer: B
Near-gain adjusts amplification of echoes from shallow (near) tissues, influencing their
brightness .
