Certified Diagnostic Ophthalmic Sonographer (CDOS) Practice Test

Prepare for the Certified Diagnostic Ophthalmic Sonographer (CDOS) examination with a comprehensive practice resource designed to strengthen your knowledge of ophthalmic ultrasound principles, diagnostic techniques, and real-world clinical decision-making. This exam preparation package includes 700+ practice questions with detailed explanations covering essential CDOS concepts, case-based scenarios, imaging interpretation, and practical sonography applications.

Built for serious exam candidates, this resource helps you identify knowledge gaps, improve test-taking confidence, and understand how diagnostic ophthalmic ultrasound is applied in actual clinical environments.

What Is Included in This CDOS Practice Test?

This CDOS exam prep resource provides realistic practice questions that simulate the style, difficulty, and clinical reasoning required for the certification examination.

You will get:

• 700+ Certified Diagnostic Ophthalmic Sonographer practice questions and answers
• Detailed answer explanations for every question
• Case-based and clinical scenario questions
• Practical ultrasound interpretation questions
• Ocular pathology identification questions
• A-scan and B-scan ultrasound practice
• Retinal and vitreous disorder scenarios
• Tumor evaluation and ocular oncology questions
• Biometry and intraocular lens calculation concepts
• Emergency ophthalmic ultrasound situations
• Quality assurance and professional practice questions
• Exam-style multiple-choice questions with correct answers

Each question is designed to test both theoretical knowledge and practical application, helping you prepare for the challenges of the CDOS certification exam.

Who Can Take the CDOS Certification Exam?

The Certified Diagnostic Ophthalmic Sonographer examination is designed for professionals who perform or support ophthalmic ultrasound procedures and want to validate their diagnostic imaging skills.

This practice test is useful for:

• Ophthalmic sonography students
• Ophthalmic ultrasound technicians
• Diagnostic ophthalmic imaging professionals
• Ophthalmology department staff
• Eye care professionals preparing for certification
• Healthcare professionals expanding into ocular imaging
• Candidates reviewing CDOS exam content before test day

Whether you are beginning your CDOS preparation or completing final exam review, this resource provides structured practice for improving knowledge and confidence.

Core Domains Covered in This CDOS Practice Exam

The practice questions cover the major knowledge areas required for diagnostic ophthalmic sonography competency.

Core areas include:

• Ophthalmic ultrasound physics and instrumentation
• A-scan biometry principles
• B-scan diagnostic imaging techniques
• Ocular anatomy and physiology
• Retinal pathology assessment
• Vitreous disorders and abnormalities
• Choroidal diseases and tumors
• Orbital ultrasound evaluation
• Ocular trauma assessment
• Postoperative eye imaging
• Intraocular lens calculation concepts
• Ultrasound artifacts and troubleshooting
• Quality assurance standards
• Patient safety and professional responsibilities

The questions focus on practical knowledge that CDOS candidates need for both examination success and clinical application.

Topics Covered in the CDOS Practice Test

This exam preparation material includes advanced topics frequently encountered in ophthalmic ultrasound practice.

Major topics include:

• Retinal detachment diagnosis and classification
• Rhegmatogenous, tractional, and exudative retinal detachments
• Proliferative vitreoretinopathy evaluation
• Posterior vitreous detachment assessment
• Vitreous hemorrhage interpretation
• Endophthalmitis ultrasound findings
• Choroidal melanoma evaluation
• Choroidal metastasis identification
• Choroidal hemangioma characteristics
• Choroidal osteoma imaging
• Retinoblastoma ultrasound findings
• Posterior scleritis evaluation
• Optic nerve disorders
• Orbital masses and inflammatory conditions
• Intraocular foreign bodies
• Trauma-related ocular emergencies
• Silicone oil and gas tamponade imaging
• Post-retinal surgery evaluation
• Tumor measurement techniques
• Ophthalmic ultrasound documentation standards

How This CDOS Practice Test Was Created

This practice test was developed using a clinical exam-style approach focused on realistic ophthalmic ultrasound situations rather than simple memorization.

Development approach includes:

• Reviewing important CDOS knowledge areas
• Creating clinically realistic patient scenarios
• Including interpretation-based ultrasound questions
• Covering both basic and advanced concepts
• Testing decision-making skills used in clinical practice
• Adding detailed explanations to reinforce understanding
• Avoiding repeated questions and duplicated concepts

The goal is to help candidates understand why an answer is correct, not just memorize information.

Effective Study Tips for CDOS Exam Preparation

A structured study approach can significantly improve your performance on the certification exam.

Recommended study strategies:

• Review ophthalmic anatomy before advanced pathology topics
• Practice ultrasound interpretation regularly
• Focus on understanding A-scan and B-scan principles
• Review common retinal and choroidal disorders
• Study ultrasound artifacts and troubleshooting methods
• Practice case-based questions frequently
• Review explanations after every practice session
• Track weak areas and revisit difficult concepts
• Combine textbook learning with question practice

Consistent practice helps develop the clinical reasoning skills required for the CDOS examination.

Weekly Study Schedule for CDOS Exam Success

A planned schedule helps organize your preparation and prevents last-minute studying.

Example 6-week CDOS study plan:

Week 1:

• Review ultrasound physics
• Study ocular anatomy
• Practice basic imaging concepts

Week 2:

• Focus on A-scan biometry
• Review measurement techniques
• Practice calculation-related questions

Week 3:

• Study retinal and vitreous disorders
• Practice detachment-related scenarios

Week 4:

• Review tumors, choroidal diseases, and orbital pathology
• Complete advanced case questions

Week 5:

• Practice emergency cases
• Review postoperative imaging
• Improve weak areas

Week 6:

• Complete full practice exams
• Review explanations
• Focus on final exam readiness

Common Mistakes to Avoid During CDOS Exam Preparation

Many candidates struggle because they focus only on memorization instead of clinical understanding.

Avoid these mistakes:

• Memorizing answers without understanding concepts
• Ignoring ultrasound physics principles
• Neglecting image interpretation practice
• Skipping explanations after incorrect answers
• Failing to review retinal attachment patterns
• Underestimating tumor evaluation concepts
• Not practicing time management
• Studying only one topic area

Understanding the reasoning behind ultrasound findings is one of the most effective ways to improve exam performance.

Why Choose This CDOS Practice Test Resource?

This CDOS practice exam is designed for candidates who want realistic preparation with clinically focused questions and explanations.

Key benefits:

• Covers 700+ exam-style practice questions
• Builds confidence before certification testing
• Improves diagnostic reasoning skills
• Reinforces important ophthalmic ultrasound concepts
• Helps identify weak knowledge areas
• Provides practical case-based learning
• Supports efficient self-paced preparation

Prepare With Confidence for the Certified Diagnostic Ophthalmic Sonographer Exam

The CDOS certification exam requires strong knowledge of ultrasound technology, ocular anatomy, pathology recognition, and clinical application. This practice test gives you the opportunity to review essential concepts, practice realistic questions, and strengthen your exam readiness.

Start preparing today with a comprehensive CDOS study resource created to support your certification goals and professional growth in diagnostic ophthalmic sonography.

CDOS Sample Questions and Answers

Question 1. A 67-year-old patient with a dense vitreous hemorrhage is referred for B-scan ultrasonography because the fundus cannot be visualized. Which sonographic finding most strongly suggests a rhegmatogenous retinal detachment rather than a posterior vitreous detachment?

A. Thin mobile membrane crossing the optic nerve head
B. Thick V-shaped membrane attached to the optic disc and ora serrata
C. Numerous low-reflective vitreous opacities without membrane formation
D. Smooth dome-shaped elevation without optic nerve attachment

Correct Answer: B

Answer Explanation: A rhegmatogenous retinal detachment typically appears on B-scan as a thick, highly reflective membrane anchored at both the optic disc and ora serrata, creating a characteristic V-shaped configuration. Unlike posterior vitreous detachment, the detached retina remains fixed at these attachment sites and demonstrates restricted mobility during dynamic examination. A posterior vitreous detachment usually presents as a thin, highly mobile membrane that moves independently and often crosses over the optic nerve head. Correctly distinguishing these conditions is critical because retinal detachment generally requires urgent surgical intervention, whereas posterior vitreous detachment is frequently managed conservatively unless retinal tears are identified.

Question 2. During an A-scan biometric examination, repeated measurements show significant variability despite correct patient fixation. What is the most likely technical cause?

A. Excessive gain settings creating artifact
B. Corneal compression from the probe
C. Increased vitreous opacities
D. Large pupil diameter

Correct Answer: B

Answer Explanation: Corneal compression is a common source of inaccurate axial length measurements during contact A-scan biometry. Excessive pressure shortens the measured axial length by flattening the cornea, resulting in inconsistent values and increasing the risk of postoperative refractive error following cataract surgery. A skilled ophthalmic sonographer should maintain minimal probe pressure and obtain multiple reproducible measurements before accepting the final value. Modern immersion techniques significantly reduce compression artifacts and generally provide more reliable results. Recognition of compression-related errors is an essential competency because even small measurement inaccuracies can substantially affect intraocular lens power calculations.

Question 3. A patient presents with suspected choroidal melanoma. Which ultrasonographic characteristic is most consistent with this diagnosis?

A. High internal reflectivity with calcification
B. Low-to-medium internal reflectivity and acoustic hollowness
C. Thin membrane with marked after-movement
D. Multiple cystic lesions without vascularity

Correct Answer: B

Answer Explanation: Choroidal melanoma characteristically demonstrates low-to-medium internal reflectivity on standardized A-scan and often exhibits acoustic hollowness on B-scan imaging. The lesion usually appears dome-shaped or mushroom-shaped if it has broken through Bruch’s membrane. Internal vascularity may also be present. These findings help differentiate melanoma from benign lesions such as choroidal hemangioma, which typically demonstrates high internal reflectivity. Ultrasound remains particularly valuable when direct visualization is limited or when lesion thickness must be accurately measured for treatment planning, including plaque brachytherapy or monitoring tumor progression.

Question 4. Which ultrasound principle explains why highly calcified intraocular lesions produce posterior acoustic shadowing?

A. Refraction
B. Doppler shift
C. High acoustic attenuation
D. Frequency modulation

Correct Answer: C

Answer Explanation: Calcified structures strongly attenuate ultrasound waves because they absorb and reflect most of the transmitted sound energy. As a result, little or no ultrasound penetrates beyond the calcified lesion, creating posterior acoustic shadowing. This phenomenon is commonly observed in retinoblastoma, optic disc drusen, and scleral calcifications. Recognizing posterior shadowing helps identify calcified lesions and distinguish them from soft tissue masses. Understanding acoustic attenuation is fundamental in diagnostic ophthalmic sonography because tissue composition directly influences image interpretation and diagnostic accuracy.

Question 5. During dynamic B-scan evaluation, a membrane demonstrates rapid undulating movement with eye motion and crosses the optic nerve head. What is the most likely diagnosis?

A. Total retinal detachment
B. Posterior vitreous detachment
C. Choroidal detachment
D. Suprachoroidal hemorrhage

Correct Answer: B

Answer Explanation: Posterior vitreous detachment typically appears as a thin, highly mobile membrane that moves freely with ocular motion and frequently crosses over the optic nerve head. In contrast, retinal detachment remains tethered to the optic disc and ora serrata, limiting its movement. Choroidal detachments are smooth, thick, dome-shaped elevations that do not cross the optic nerve. Dynamic examination is an essential component of ophthalmic ultrasonography because observing tissue mobility often provides diagnostic information that static images alone cannot reveal.

Question 6. A cataract surgeon requests axial length confirmation because the difference between both eyes exceeds 1.5 mm. What should the ophthalmic sonographer do first?

A. Immediately average all previous measurements
B. Repeat measurements while verifying alignment and fixation
C. Select the shortest measurement obtained
D. Increase gain to improve image brightness

Correct Answer: B

Answer Explanation: A significant interocular axial length difference warrants careful verification before reporting results. The sonographer should repeat measurements while ensuring correct alignment with the visual axis, stable fixation, minimal corneal compression, and consistent echo patterns. Axial length errors can produce substantial postoperative refractive surprises after cataract surgery. Averaging inaccurate measurements or selecting the shortest value without verification increases the likelihood of incorrect intraocular lens selection. Quality assurance protocols emphasize reproducibility before accepting final biometric data.

Question 7. Which ocular structure normally generates the strongest echo during standardized A-scan examination?

A. Vitreous body
B. Retina-choroid-sclera complex
C. Lens nucleus
D. Aqueous humor

Correct Answer: B

Answer Explanation: The retina-choroid-sclera complex produces one of the strongest echoes in standardized A-scan because it represents a major acoustic interface between tissues of differing acoustic impedance. In contrast, the vitreous and aqueous humors are normally echo-free, while the crystalline lens produces characteristic anterior and posterior capsule echoes. Recognizing normal echo patterns enables the sonographer to identify abnormal tissue reflectivity associated with tumors, hemorrhage, retinal pathology, or inflammatory disease. Knowledge of normal anatomy is essential for accurate diagnostic interpretation.

Question 8. A patient experiences severe blunt ocular trauma. B-scan demonstrates smooth, thick dome-shaped elevations extending into the vitreous cavity without attachment to the optic disc. Which diagnosis is most likely?

A. Retinal detachment
B. Choroidal detachment
C. Posterior vitreous detachment
D. Vitreous syneresis

Correct Answer: B

Answer Explanation: Choroidal detachment typically appears as smooth, thick, dome-shaped elevations caused by fluid or blood accumulating in the suprachoroidal space. Unlike retinal detachments, choroidal detachments are not attached to the optic disc and often involve multiple quadrants. Trauma, hypotony, postoperative complications, and inflammation are common causes. Recognizing these distinctive ultrasound characteristics assists ophthalmologists in determining the underlying cause and selecting appropriate management, including observation, drainage, or surgical intervention depending on severity.

Question 9. Which transducer frequency is most commonly used for routine diagnostic ophthalmic B-scan examinations?

A. 2 MHz
B. 5 MHz
C. 10 MHz
D. 20 MHz

Correct Answer: C

Answer Explanation: A 10 MHz transducer provides an optimal balance between image resolution and tissue penetration for routine ophthalmic B-scan examinations. Higher frequencies improve visualization of small ocular structures while maintaining sufficient penetration through the globe. Lower-frequency probes are generally unnecessary because the eye is a superficial organ. Frequencies substantially above 10 MHz may provide greater detail but reduced penetration, making them more appropriate for specialized anterior segment imaging rather than standard posterior segment evaluation.

Question 10. A patient with diabetic vitreous hemorrhage undergoes serial B-scans. Which finding most strongly indicates tractional retinal detachment?

A. Freely mobile vitreous echoes only
B. Thick immobile membrane with focal vitreoretinal attachment points
C. Uniform diffuse vitreous haze
D. Small posterior vitreous floater

Correct Answer: B

Answer Explanation: Tractional retinal detachment develops when fibrovascular membranes contract and pull the retina away from the underlying tissue. On ultrasound, the detached retina appears thick and relatively immobile, with visible traction points extending toward the vitreous. This differs from rhegmatogenous detachment, which results from retinal tears, and from isolated vitreous hemorrhage, which produces mobile low-level echoes. Accurate identification influences surgical planning because tractional detachments frequently require pars plana vitrectomy and membrane dissection rather than simple retinal repair.

Question 11. During standardized A-scan tissue characterization, which lesion generally demonstrates the highest internal reflectivity?

A. Choroidal melanoma
B. Choroidal hemangioma
C. Retinoblastoma without calcification
D. Metastatic melanoma

Correct Answer: B

Answer Explanation: Choroidal hemangiomas usually display high internal reflectivity because they consist of densely packed vascular channels that efficiently reflect ultrasound waves. Choroidal melanomas generally exhibit lower internal reflectivity and acoustic hollowness. Differentiating these lesions is clinically important because treatment strategies differ considerably. Ultrasound findings are interpreted alongside clinical examination, optical coherence tomography, fluorescein angiography, and other imaging studies to establish the most accurate diagnosis and determine appropriate follow-up or intervention.

Question 12. Which factor has the greatest influence on axial resolution in diagnostic ophthalmic ultrasound?

A. Display brightness
B. Ultrasound frequency
C. Patient age
D. Scan duration

Correct Answer: B

Answer Explanation: Axial resolution primarily depends on ultrasound frequency and pulse length. Higher-frequency transducers generate shorter wavelengths, allowing two closely spaced structures lying along the beam path to be distinguished more accurately. Ophthalmic ultrasound benefits from high frequencies because the eye is relatively superficial and requires excellent spatial resolution. Although increasing frequency reduces penetration depth, this limitation is generally acceptable in ocular imaging. Understanding resolution principles helps optimize equipment settings for diagnostic accuracy.

Question 13. During immersion A-scan biometry, what is the principal advantage compared with contact A-scan?

A. Faster examination time
B. Elimination of corneal compression errors
C. Lower equipment cost
D. Reduced patient cooperation requirements

Correct Answer: B

Answer Explanation: Immersion A-scan prevents direct contact between the probe and the cornea by using a saline-filled shell, eliminating corneal compression and improving measurement accuracy. This technique is particularly valuable for precise intraocular lens calculations because even minimal compression during contact biometry can shorten axial length measurements. Although immersion requires additional preparation, it generally produces more consistent and reproducible results. Accurate biometric measurements directly contribute to improved postoperative refractive outcomes in cataract surgery.

Question 14. A patient with suspected endophthalmitis undergoes B-scan imaging because corneal edema prevents fundus examination. Which sonographic finding is most suggestive of severe intraocular infection?

A. Clear anechoic vitreous cavity
B. Dense vitreous echoes with membranous debris
C. Thin mobile posterior vitreous membrane only
D. Isolated optic nerve enlargement

Correct Answer: B

Answer Explanation: Endophthalmitis commonly produces dense, disorganized vitreous echoes representing inflammatory cells, fibrin, exudate, and debris within the vitreous cavity. Membrane formation may also occur in advanced infection. Ultrasound is particularly valuable when media opacity prevents direct visualization of the posterior segment. Detecting associated retinal detachment, choroidal detachment, or abscess formation helps guide urgent treatment decisions. Prompt diagnosis and intervention are essential because delayed management significantly increases the risk of permanent vision loss.

Question 15. Which scanning technique best evaluates membrane mobility within the vitreous cavity?

A. Static longitudinal scan only
B. Dynamic examination during eye movement
C. Single transverse image only
D. Standardized A-scan exclusively

Correct Answer: B

Answer Explanation: Dynamic B-scan examination requires the patient to move the eyes while the examiner observes tissue movement in real time. Membrane mobility helps distinguish retinal detachment, posterior vitreous detachment, vitreous membranes, and hemorrhage. Static images alone may not reveal these critical differences. Dynamic assessment also improves lesion localization and demonstrates tractional forces acting upon the retina. Incorporating real-time motion analysis is considered a standard component of comprehensive ophthalmic ultrasonography.

Question 16. A patient with leukocoria is evaluated using ophthalmic ultrasound. Which finding is highly suggestive of retinoblastoma?

A. Mobile vitreous membranes without mass
B. Intraocular mass containing calcification with acoustic shadowing
C. Dome-shaped choroidal elevation
D. Uniform vitreous hemorrhage

Correct Answer: B

Answer Explanation: Retinoblastoma frequently contains calcified foci that produce highly reflective echoes with prominent posterior acoustic shadowing. The presence of an intraocular mass with calcification in a child strongly supports this diagnosis and distinguishes it from conditions such as persistent fetal vasculature or Coats disease. Ultrasound plays a vital role when direct visualization is difficult and helps determine tumor size, extent, and associated retinal detachment. Early diagnosis significantly improves survival and vision-preserving treatment options.

Question 17. Which quality control practice is most important before documenting final biometric measurements?

A. Accept the first acceptable reading
B. Confirm multiple consistent measurements within acceptable tolerance
C. Increase gain to maximum
D. Average measurements from both eyes

Correct Answer: B

Answer Explanation: Reliable ophthalmic biometry requires multiple reproducible measurements demonstrating acceptable agreement before the final value is recorded. Consistency confirms proper probe alignment, adequate fixation, and absence of technical error. Accepting a single measurement increases the risk of inaccurate intraocular lens calculations. Quality assurance standards emphasize repeatability because precise axial length determination is one of the most influential variables affecting postoperative refractive success following cataract extraction.

Question 18. During B-scan imaging, a highly reflective foreign body is identified within the vitreous cavity. Which additional sonographic feature most strongly supports the diagnosis of a metallic intraocular foreign body?

A. Complete absence of echoes
B. Reverberation artifact behind the object
C. Uniform low reflectivity
D. Posterior vitreous detachment

Correct Answer: B

Answer Explanation: Metallic foreign bodies frequently generate reverberation artifacts because ultrasound waves repeatedly bounce between reflective metallic surfaces and the transducer. These multiple parallel echoes appear posterior to the object and assist in confirming its metallic nature. Foreign body localization is essential for surgical planning, particularly following penetrating ocular trauma. The sonographer should also evaluate for associated complications including retinal detachment, vitreous hemorrhage, lens injury, and choroidal damage.

Question 19. Which patient instruction most improves image quality during a routine posterior segment B-scan examination?

A. Keep both eyes tightly closed throughout the examination
B. Follow directional eye movement commands while maintaining relaxed eyelids
C. Blink continuously during scanning
D. Avoid moving the unaffected eye

Correct Answer: B

Answer Explanation: Patient cooperation is essential for obtaining high-quality ophthalmic ultrasound images. Following directional gaze commands allows the sonographer to visualize different retinal quadrants, evaluate lesion mobility, and perform comprehensive dynamic assessment. Relaxed eyelids reduce unnecessary pressure on the globe and improve patient comfort. Clear communication throughout the examination minimizes motion artifacts and ensures complete visualization of the posterior segment, especially when assessing retinal pathology or intraocular masses.

Question 20. A patient with severe media opacity undergoes B-scan ultrasonography before cataract surgery. Why is this examination clinically important?

A. It determines corneal endothelial cell count
B. It evaluates hidden posterior segment pathology that may affect surgical planning and visual prognosis
C. It measures intraocular pressure directly
D. It replaces postoperative retinal examination

Correct Answer: B

Answer Explanation: Dense cataracts and other media opacities may prevent direct visualization of the retina and vitreous before surgery. Preoperative B-scan ultrasonography allows identification of retinal detachment, intraocular tumors, vitreous hemorrhage, posterior staphyloma, and other abnormalities that could significantly alter surgical planning or expected visual outcomes. Detecting occult posterior segment disease enables informed patient counseling and appropriate referral when necessary. Comprehensive preoperative evaluation is a key responsibility of the Certified Diagnostic Ophthalmic Sonographer and contributes directly to safe, effective ophthalmic care.

Question 21. A patient with dense vitreous hemorrhage from proliferative diabetic retinopathy undergoes B-scan ultrasonography. During kinetic examination, a broad membrane extends from the optic nerve head but demonstrates localized areas where the retina appears tented toward the vitreous cavity while adjacent retina remains attached. What is the most appropriate interpretation?

A. Focal vitreoretinal traction with impending tractional retinal detachment
B. Complete posterior vitreous detachment
C. Vitreous syneresis with condensed collagen fibers
D. Chronic choroidal detachment

Correct Answer: A

Answer Explanation: Localized retinal tenting without complete retinal separation is highly suggestive of focal vitreoretinal traction. Fibrovascular membranes exert traction on isolated retinal areas before a complete tractional retinal detachment develops. Dynamic B-scan is particularly valuable because the traction point demonstrates restricted movement compared with adjacent retina. Identifying focal traction is clinically important since early surgical intervention may prevent progression to irreversible retinal detachment. Careful documentation should describe the exact location, extent of traction, associated hemorrhage, and retinal mobility to assist vitreoretinal surgical planning.

Question 22. During standardized A-scan evaluation of a suspicious choroidal lesion, the internal reflectivity gradually decreases from the lesion surface toward its base without abrupt changes. Which pathological feature most likely explains this finding?

A. Homogeneous cellular architecture typical of malignant melanoma
B. Extensive intralesional calcification
C. Multiple vascular sinusoids of a hemangioma
D. Chronic organized vitreous hemorrhage

Correct Answer: A

Answer Explanation: Choroidal melanoma frequently demonstrates gradually decreasing internal reflectivity because its densely packed melanocytic cells create relatively uniform acoustic characteristics. This pattern differs from vascular tumors such as hemangiomas, which generally produce numerous high-amplitude internal echoes from blood-filled channels. Standardized A-scan analysis remains valuable for tumor characterization, particularly when combined with lesion shape, thickness, vascularity, and clinical examination. Understanding internal reflectivity patterns helps differentiate melanomas from other intraocular tumors while improving diagnostic confidence.

Question 23. A patient who underwent scleral buckle surgery one year earlier presents with recurrent visual symptoms. Which sonographic finding most strongly suggests recurrent retinal detachment rather than postoperative buckle indentation?

A. Mobile retinal elevation extending beyond the buckle with persistent subretinal fluid
B. Stable localized scleral indentation without retinal elevation
C. Uniform scleral thickening beneath the buckle only
D. Bright scleral echoes without retinal movement

Correct Answer: A

Answer Explanation: A scleral buckle normally produces localized indentation of the globe without retinal elevation. Recurrent retinal detachment is suggested by persistent subretinal fluid and a mobile elevated retina extending beyond the buckle margins. Dynamic scanning helps distinguish recurrent detachment from expected postoperative anatomy. Documentation should include buckle position, retinal attachment status, extent of recurrent detachment, and associated proliferative vitreoretinopathy. Accurate differentiation influences the need for repeat vitreoretinal surgery.

Question 24. During evaluation of suspected posterior scleritis, which additional ultrasound finding besides the T-sign most strongly supports the diagnosis?

A. Diffuse posterior scleral thickening exceeding normal limits
B. Complete posterior vitreous detachment
C. Retinal tear at the ora serrata
D. Uniform vitreous liquefaction

Correct Answer: A

Answer Explanation: Posterior scleritis characteristically demonstrates diffuse thickening of the posterior sclera together with fluid accumulation in Tenon’s capsule, producing the classic T-sign. Scleral thickening reflects active inflammation and helps differentiate posterior scleritis from orbital masses or retinal disorders. Additional findings may include exudative retinal detachment or choroidal thickening. Ultrasound plays a critical role because the posterior sclera is not directly visible during routine ophthalmic examination.

Question 25. A sonographer notices that repeated axial length measurements differ by approximately 0.35 mm despite correct immersion technique. Which troubleshooting step should be performed first?

A. Reassess visual axis alignment before accepting any measurements
B. Increase ultrasound output power substantially
C. Switch immediately to contact biometry
D. Average all measurements regardless of variation

Correct Answer: A

Answer Explanation: Measurement variation greater than accepted limits usually indicates off-axis alignment, unstable fixation, or poor technique rather than true anatomical variation. The first corrective step is reassessing visual axis alignment while ensuring steady fixation and proper transducer positioning. Accepting inconsistent measurements may produce clinically significant intraocular lens power errors. Averaging inaccurate measurements does not improve accuracy. High-quality ophthalmic biometry requires multiple reproducible measurements obtained using standardized technique.