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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?
- 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.
- 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.
7. The primary advantage of ultrasound biomicroscopy (UBM) over conventional B-scan is: - A) Greater depth penetration - B) Higher frequency providing superior anterior segment resolution - C) Ability to image the retina directly - D) Use of Doppler flow imaging Answer: B UBM uses 35–50 MHz frequencies, yielding micrometer-scale resolution of anterior segment structures. 8. Which B-scan appearance is characteristic of a total retinal detachment? - A) "V-shape" attached to the optic disc - B) "T-sign" at the posterior sclera - C) Crescent-shaped membrane floating freely - D) Homogeneous low-reflectivity area in vitreous
- B) Collar-button configuration with low-to-medium reflectivity
- C) Thin avascular retinal membrane
- D) Complete absence of internal echoes Answer: B Choroidal melanoma often demonstrates low-to-medium internal reflectivity with acoustic hollowness and possible collar-button (mushroom) morphology due to breakthrough of Bruch's membrane. 11. High internal reflectivity on B-scan of an intraocular mass suggests:
- A) Choroidal melanoma
- B) Choroidal hemangioma
- C) Metastatic carcinoma
- D) Retinoblastoma Answer: B Choroidal hemangiomas typically exhibit high, homogeneous internal reflectivity, whereas melanomas are low-to-moderate.
12. The speed of sound in the vitreous humor is approximately: - A) 1450 m/s - B) 1540 m/s - C) 1600 m/s - D) 1700 m/s Answer: B The vitreous has a sound velocity close to that of water, about 1540 m/s, which is used for most ocular calculations. 13. In biometric calculations, a longer axial length generally requires: - A) Higher IOL power - B) Lower IOL power - C) No change in IOL power - D) A switch to a different formula only
- C) Homogeneous medium reflectivity without shadow
- D) Hyper-vascular flow on Doppler only Answer: B Calcifications in retinoblastoma create strong reflections and posterior acoustic shadowing. 16. The optic nerve sheath diameter (ONSD) is measured to assess:
- A) Glaucoma severity
- B) Elevated intracranial pressure (papilledema)
- C) Corneal thickness
- D) Lens density Answer: B ONSD measurement is used to assess elevated intracranial pressure; the optic nerve sheath distends when intracranial pressure increases. 17. Which extraocular muscle is most commonly involved in Graves' ophthalmopathy?
- A) Superior rectus
- B) Inferior rectus
- C) Medial rectus
- D) Lateral rectus Answer: C Graves' disease commonly causes bilateral enlargement of the inferior and medial rectus muscles; the medial rectus is most frequently noted. 18. What is the primary determinant of acoustic impedance in ocular tissues?
- A) Temperature
- B) Density and sound speed product
- C) Frequency of the ultrasound wave
- D) Electrical conductivity
- B) Highly reflective, stationary vitreous bodies
- C) Small, highly reflective dots within the vitreous that are mobile
- D) Uniformly echogenic vitreous with no discrete structures Answer: C Asteroid hyalosis consists of calcium-laden bodies that are highly reflective and move with vitreous currents. 21. The "T-sign" on B-scan is most indicative of which condition?
- A) Choroidal melanoma
- B) Posterior scleritis
- C) Retinal detachment
- D) Vitreous hemorrhage Answer: B Posterior scleritis creates a hypoechoic fluid collection adjacent to the sclera, producing a T- shaped echogenic line.
22. An intraocular foreign body (IOFB) composed of metal will most likely produce which artifact on B-scan? - A) Acoustic shadowing - B) Posterior enhancement - C) Reverberation - D) Ring-down artifact Answer: A Metallic objects strongly reflect and absorb ultrasound, casting a pronounced acoustic shadow distal to the object. 23. Which scanning technique is most appropriate for evaluating a suspected retinal tear located at the 6 o'clock position? - A) Superior transverse sweep - B) Inferior longitudinal sweep
25. Which ocular layer contains the choroidal vasculature that supplies the outer retina? - A) Sclera - B) Iris - 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. 26. What is the term for the normal posterior bulge or outpouching of the sclera seen in high myopia? - A) Posterior staphyloma - B) Scleral ectasia - C) Optic disc drusen - D) Choroidal detachment
Answer: A A staphyloma is an outpouching of the posterior aspect of the globe commonly associated with high myopia with axial lengths > 26.5 mm.
27. The retina is divided into which two primary layers? - A) Neurosensory retina and retinal pigment epithelium (RPE) - B) Inner retina and outer retina - C) Macula and periphery - D) Rod layer and cone layer Answer: A The retina consists of the neurosensory retina (neural tissue) and the retinal pigment epithelium (RPE), which supports photoreceptor function. 28. In UBM, a plateau iris configuration is identified by: - A) Anteriorly bowed iris root with a normal angle
30. The presence of a cyclodialysis cleft on UBM appears as: - A) A hyperechoic line crossing the ciliary body - B) A discontinuity between the ciliary body and scleral spur with a fluid cleft - C) A uniform thickening of the ciliary body - D) A posteriorly displaced lens capsule Answer: B Cyclodialysis cleft creates a separation (fluid-filled cleft) between the ciliary body and scleral spur, visible as a hypoechoic gap. 31. Which of the following best describes the relationship between ultrasound frequency and axial resolution? - A) Higher frequency → lower axial resolution - B) Higher frequency → higher axial resolution - C) Frequency does not affect axial resolution - D) Lower frequency → higher axial resolution
Answer: B Axial resolution improves with higher frequency because shorter wavelengths can distinguish closely spaced reflectors.
32. In time-gain control (TGC), adjusting the deeper segment of the control bar will: - A) Increase gain for superficial structures only - B) Decrease overall system gain - C) Compensate for attenuation of deeper echoes - D) Change the transducer frequency Answer: C TGC allows selective amplification of echoes from particular depth ranges, correcting for depth- related attenuation. 33. Which A-scan spike corresponds to the anterior corneal surface? - A) First spike
