Technique

Technique

Position:  Supine or head elevated at 30 degrees, on the bed or in a caregiver’s lap

1. Gather your equipment and select the ocular/ophthalmic preset*

2. Have the child close their eye and apply the Tegaderm adhesive (if available).

· If no Tegaderm adhesive is available, it is essential the child keeps their eye closed throughout the exam and to use sterile gel

· Ensure to press firmly at the inner canthus to avoid having air bubble under the Tegaderm

3. Apply a copious amount of sterile gel over the affected eye so the probe floats on the surface, minimizing pressure on the globe.

4. Place the probe in the transverse position over the affected eye (probe marker pointing towards the patients right) (figure 2).

5. Fan the probe superiorly and inferiorly until the anatomy of the eye is clearly visualized

6. Fully scan through the eye from superior to inferior, assessing the anatomy throughout. Document findings

7. Assess extraocular movements – ask the child to move their eyes left and right

8. Rotate the probe 90 degrees clockwise (probe marker facing cranially) to assess in the sagittal plane (figure 3).

9. Fan the probe medially and laterally until the anatomy of the eye is clearly visualized

10. Fully scan through the eye from medial to lateral, assessing the anatomy throughout. Document findings

11. If uncertain of findings, assess the non-affected eye to compare

 

 

Figure 2. Transverse probe position during ocular PoCUS with Tegaderm and copious gel

 

Figure 3. Sagittal probe position during ocular PoCUS with Tegaderm and copious gel

Indications

Indications 

  • Ocular trauma
  • Acute eye pain 
  • Intraocular foreign body 
  • Vision loss 
  • Infection
  • Change of vision
  • Difficult and/or inconclusive fundoscopic exam
  • Leukocoria 

Contraindications 

  • Suspected globe rupture 

 

Equipment 

  • US machine 
  • High frequency linear probe 
  • Tegaderm transparent adhesive 
  • Sterile Gel

Preset

  • Ocular/ophthalmic preset

* The eye is more vulnerable to the bioeffects of ultrasound than most other body tissues. For this reason, it is essential to maintain very low mechanical index (MI) and thermal index (TI) during ocular scanning to minimize the theoretical risk of tissue damage [3]. If your POCUS system does not provide a dedicated ocular/ophthalmic preset, the MI should be set at 0.23 or lower and the TI of 1.0 or lower [17-19]. Doppler modes (color and pulsed wave) increase acoustic output, and such, their use is not recommended in pediatric ocular POCUS. 

The MI/TI can be found on the imaging screen on most PoCUS machines. (Figure 1) 

 

Figure 1. Acceptable MI and TI as seen on ophthalmic preset of a Sonosite PoCUS unit. 

 

Introduction

Ocular complaints are a common reason for presentation to the pediatric emergency department (ED). According to a five-year retrospective study in Ontario, children accounted for approximately 19% of the 774,057 eye-related ED visits, underscoring the substantial pediatric burden of ocular emergencies [1]. While many cases are benign, some may reflect serious ocular trauma or underlying systemic or neurological disease, making timely recognition and referral essential for preserving vision and preventing complications [2]. 

Ocular complaints, particularly in children, represent a diagnostic challenge to many non-ophthalmology specialists. Traditional diagnostic methods, such as direct fundoscopic examination performed by non-experts, can be challenging given the limited collaboration of the younger pediatric patients.  Other modalities such as computed tomography (CT), or magnetic resonance imaging (MRI), can be time-consuming, expose children to radiation, require transportation and sedation, and may not always be readily available. Furthermore, ophthalmology consultation may not be readily available for evaluation of children presenting to the ED. 

In recent years, point-of-care ultrasound (PoCUS) has emerged as a valuable tool for evaluating ocular complaints in the pediatric ED. It allows for rapid, bedside imaging performed by emergency physicians, providing real-time diagnostic information without the typical challenges associated with fundoscopic exam [3]. As PoCUS becomes increasingly integrated into pediatric emergency care, there is a growing body of evidence supporting its clinical utility in detecting ocular abnormalities [3-6]. Given the frequency of ocular complaints in children and the need for a more user-friendly diagnostic tool, PoCUS offers a compelling adjunct to fundoscopy and other imaging (CT/MRI) in appropriate clinical contexts. 

 

This module focuses on the normal and abnormal anatomy of the pediatric eye, providing learners with the foundational skills to identify common anterior and posterior segment findings using PoCUS. Assessment of the optic nerve for raised intracranial pressure or papilledema is beyond the scope of this module and is addressed in detail in a separate KidSONO module. 

 

Why Ultrasound?

Traditionally, bedside emergency evaluation of ocular pathology has relied on physical examination and direct fundoscopy. Direct fundoscopy is the primary examination for visualizing posterior segment pathology, including retinal detachment, vitreous detachment, vitreous hemorrhage, and intraocular masses, with MRI occasionally used for deeper structural or space-occupying lesions. However, fundoscopy presents significant challenges, particularly in children and when performed by non-ophthalmologists. It can be technically difficult to carry out, and many non-ophthalmology physicians report a lack of confidence in performing and accurately interpreting the exam [7-10]. Children’s cooperation can be particularly limited due to young age, developmental stage, anxiety, or fear, all of which may compromise the reliability of fundoscopic findings [3]. Moreover, the technique is known to have high false-negative rates when performed by non-ophthalmologists, emphasizing its dependency on examiner expertise [9]. Assessment of anterior segment pathology such as intraocular foreign bodies, corneal injuries, or lens abnormalities, typically relies on slit-lamp examination or CT imaging. Slit lamp assessment is a challenging skill at the bedside due to equipment limitations, lack of consistent training and routine use, and patient compliance. CT carries the disadvantage of ionizing radiation exposure, which is particularly concerning in pediatric populations.  

 

PoCUS offers a valuable alternative or precursor to these conventional methods, allowing real-time visualization of both anterior and posterior ocular structures at the bedside. Its versatility, portability, cost-effectiveness, and safety have contributed to its growing role as a frontline imaging modality in pediatric care. When performed by trained emergency physicians, PoCUS has demonstrated high sensitivity and specificity for a range of ocular pathologies. In a systematic review and meta-analysis in adult populations, PoCUS achieved high sensitivity and specificity across multiple ocular conditions (Table 1) [11]. 

Table 1. Diagnostic accuracy of PoCUS [11].

 

Ocular PoCUS, like other PoCUS applications, is a skill that can be readily acquired through focused training combining didactic instruction and hands-on practice [12, 13]. It has been demonstrated that PEM physicians are able to rapidly achieve competency in ocular scanning, even for more advanced applications such as optic nerve assessment (covered in a separate KidSONO module), highlighting the overall ease and accessibility of ocular PoCUS training [14]. 

 

Given these advantages, the use of PoCUS for ocular complaints is endorsed by several professional societies  [15, 16]. While ocular PoCUS is not intended to replace fundoscopy or advanced imaging such as CT or MRI, it functions as an effective adjunctive tool to support rapid bedside diagnosis and facilitate timely ophthalmology consultation when abnormalities are detected. In practice, ocular PoCUS should be applied as a “rule-in” test, helping confirm suspected pathology and prioritize urgent referral, rather than a “rule-out” test in cases where the clinical history or presentation raises concern for serious ocular disease. 

KidSONO: Ocular

 

Author: Julia Stiz, MSc., RDMS
Secondary Author: Melanie Williman, MD, FRCPC
Reviewer(s): Jade Seguin, M.D., FRCPC ; Jackie Harrison, M.D., FRCPC

 

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References

 

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References

  1. Smith RC, Verga M, McCarthy S, Rosenfield AT. Diagnosis of acute flank pain: value of unenhanced helical CT. AJR Am J Roentgenol. 1996 Jan;166(1):97–101.
  2. Miglioretti DL, Johnson E, Williams A, Greenlee RT, Weinmann S, Solberg LI, et al. The use of computed tomography in pediatrics and the associated radiation exposure and estimated cancer risk. JAMA Pediatr. 2013 Aug 1;167(8):700–7.
  3. Dawn s. Milliner, Mary e. Murphy. Urolithiasis in Pediatric Patients. Mayo Clinic Proceedings, 1993;68(3):241-248, ISSN 0025-6196, https://doi.org/10.1016/S0025-6196(12)60043-3.
  4. Guedj R, Escoda S, Blakime P, Patteau G, Brunelle F, Cheron G. The accuracy of renal point of care ultrasound to detect hydronephrosis in children with a urinary tract infection. Eur J Emerg Med. 2015 Apr;22(2):135-8. doi: 10.1097/MEJ.0000000000000158. PMID: 24858915.
  5. Dalziel PJ, Noble VE, Bedside ultrasound and the assessment of renal colic: a review. Emergency Medicine Journal 2013;30:3-8.
  6. Smith-Bindman R, Aubin C, Bailitz J, Bengiamin RN, Camargo CA, Corbo J, et al. Ultrasonography versus computed tomography for suspected nephrolithiasis. N Engl J Med. 2014 Sep 18;371(12):1100–10.
  7. Jendeberg J, Geijer H, Alshamari M, Cierzniak B, Lidén M. Size matters: The width and location of a ureteral stone accurately predict the chance of spontaneous passage. Eur Radiol. 2017 Nov;27(11):4775–85.
  8. Goertz JK, Lotterman S. Can the degree of hydronephrosis on ultrasound predict kidney stone size? Am J Emerg Med. 2010 Sep;28(7):813–6.
  9. Taus PJ, Manivannan S, Dancel R. Bedside Assessment of the Kidneys and Bladder Using Point of Care Ultrasound. POCUS J. 2022;7(Kidney):94–104.
  10. Renal Ultrasound Made Easy: Step-By-Step Guide [Internet]. POCUS 101. [cited 2023 Dec 9]. Available from: https://www.pocus101.com/renal-ultrasound-made-easy-step-by-step-guide/
  11. Ma J, Mateer J. Ma and Mateer’s Emergency Ultrasound. 4e ed. USA: McGraw Hill; 2021.
  12. The POCUS Atlas. Renal/GU. https://www.thepocusatlas.com/renal-gu.
  13. Renal Fellow Network [Internet]. 2023 [cited 2023 Dec 10]. Renal Fellow Network. Available from: https://www.renalfellow.org/
  14. Ripollés T, Martínez-Pérez MJ, Vizuete J, Miralles S, Delgado F, Pastor-Navarro T. Sonographic diagnosis of symptomatic ureteral calculi: usefulness of the twinkling artifact. Abdom Imaging. 2013 Aug;38(4):863–9.
  15. Kidney. https://nephropocus.com/tag/kidney/.

Summary

Summary

  • The urinary tract should be evaluated by visualizing both kidneys and the collecting systems, together with the bladder.
  • Each kidney needs to be scanned in the longitudinal and transverse orientation for better identification of abnormalities.
  • Hydronephrosis will include multiple grades. It is important to familiarize yourself with the grading system.
  • The bladder is an anechoic structure. It should be evaluated in both the transverse and longitudinal orientation.
  • Ureteral jets can be viewed with the application of color Doppler in the transverse orientation.
  • Be aware of pitfalls when evaluating the renal system and bladder.

Figure 22: Summary of hydronephrosis grading. Image use with permission POCUS 101 [11]