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Applications of ocular point-of-care ultrasound assessment in the emergency setting: a scoping review

Scoping review of ocular POCUS in the ED

Article information

Clin Exp Emerg Med. 2024;.ceem.24.249
Publication date (electronic) : 2024 September 6
doi : https://doi.org/10.15441/ceem.24.249
Christopher D. Yang1,2orcid_icon, Christine K. Kim1,2, Melissa M. Chang1,2, Pooya Khosravi1,2, Ajeet Pal Bayo Bhatia1, Amanda dos Santos1, Kyle Dornhofer1orcid_icon, Megan Guy1orcid_icon, Edmund Hsu1orcid_icon, Soheil Saadat1orcid_icon, John Christian Fox,1orcid_icon
1Department of Emergency Medicine, University of California, Irvine, Orange, CA, USA
2School of Medicine, University of California, Irvine, Orange, CA, USA
Correspondence to: John Christian Fox Department of Emergency Medicine, School of Medicine, University of California, Irvine, 333 City Blvd, Suite 640, Orange, CA 92868, USA Email: jfox@hs.uci.edu
Received 2024 April 30; Revised 2024 July 27; Accepted 2024 August 14.

Abstract

Objective

To evaluate the current body of literature pertaining to the use of ocular point-of-care ultrasound (POCUS) in the emergency department (ED).

Methods

A comprehensive literature search was conducted on Scopus, Web of Science, MEDLINE, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Inclusion criteria were studies written in English and primary clinical studies involving ocular POCUS scans in an ED setting. Exclusion criteria were nonprimary studies (e.g., reviews or case reports), studies written in a non-English language, nonhuman studies, studies performed in a nonemergency setting, studies involving non-POCUS ocular ultrasound modalities, or studies published more than 10 years prior. Data extraction was guided by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations.

Results

The initial search yielded 391 results with 153 duplicates. Of the remaining 238 studies selected for retrieval and screening, 24 met the inclusion criteria. These 24 included studies encompassed 2,448 patients across prospective, retrospective, cross-sectional, and case series study designs. The majority of included studies focused on the use of POCUS in the ED to measure optic nerve sheath diameter as a proxy for papilledema and metabolic aberrations, while a minority of studies used ocular POCUS to assist in the diagnosis of orbital fractures or posterior segment pathology.

Conclusion

The vast majority of studies investigating the use of ocular POCUS in recent years emphasize its utility in measuring optic nerve sheath diameter and fluctuations in intracranial pressure, though additional outcomes of interest include pathology of the posterior segment, orbit, and globe.

Keywords: Diagnostic imaging; eye; Emergency departments

INTRODUCTION

Ocular pathology is present in nearly 10% of all emergency department (ED) visits each year [1,2]. Rapid and accurate diagnosis of ocular emergencies is critical to prevent irreversible vision loss. The ED examination for ocular emergencies includes visual acuity, pupil reactivity, intraocular pressure, extraocular muscle motility, external periorbital changes, Wood lamp examination with fluorescein staining, and fundoscopic exam without dilation. Such ED examination is conducted alongside detailed ophthalmologic examination, often conducted by an ophthalmologist, using slit-lamp microscopy and indirect fundoscopy, both of which are widely recognized as gold standard tools for diagnosing eye conditions [3]. However, the required tools may not always be available, especially in resource-limited environments. The inconvenience of dilated exams can compound these challenges.

Point-of-care ultrasound (POCUS) is a noninvasive imaging technique used as a diagnostic adjunct for detecting ocular disease. It is particularly useful for detecting fundal pathologies that are not readily appreciated on external physical exam, such as vitreous hemorrhage, retinal detachment, and retinal hemorrhage [4]. This scoping review presented here aims to evaluate the current body of primary literature on the utility of POCUS in detecting ocular pathology. By assessing the existing literature, we hope to provide insights into the feasibility, accuracy, and practical implications of POCUS as a primary or adjunctive screening tool in the ED setting.

METHODS

Search strategy

A literature search was conducted using Scopus, Web of Science, MEDLINE, and Cochrane Central Register of Controlled Trials (CENTRAL) databases using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations. Article publication dates were restricted to the last decade (earliest publication date of January 1, 2013). Search terms included “ophthal*,” “ultrasound,” “emergen*,” and “point-of-care.” The complete list of search terms, truncations, and Boolean operators used are listed in Supplementary Table 1. While a systematic review would aim to answer a specific research question by summarizing evidence on the topic, our work in this scoping review provides a broader preliminary assessment of the current body of evidence discussing the use of ocular POCUS in the emergency setting, while helping to identify knowledge gaps and inform future research.

Screening of studies

Titles and abstracts of studies were independently evaluated by three authors (CDY, CKK, and APB). These selections were then compared, and discrepancies were resolved via further discussion with the senior author (SS). Final study selections were performed independently by the three authors (CDY, CKK, and APB) after examining full-text articles. References from articles identified through our search were also evaluated and included if they met all inclusion criteria.

Inclusion and exclusion criteria

All reviewed articles were subject to the following inclusion criteria: studies written in English and primary clinical studies involving ocular POCUS scans in an ED setting. No restrictions were placed on the included number of patients or patient demographics. All reviewed articles were subject to the following exclusion criteria: nonprimary studies (e.g., reviews or case reports), studies written in a language other than English, nonhuman studies, studies performed in a nonemergency setting, and studies involving non-POCUS ocular ultrasound modalities. After articles were selected, the Methodological Index for Nonrandomized Studies (MINORS) criteria were used to evaluate the quality of nonrandomized studies and assess the risk of bias for selected studies [5]. Each item on the MINORS checklist was independently scored by two authors.

Data extraction

Following qualitative analysis, data were extracted from included articles to a predefined table (Supplementary Table 2) for the following variables: author, year of publication, country of origin, publication journal, practice setting, sonographer type (emergency physician, ophthalmologist, or radiologist), type of study (e.g., prospective/retrospective, cross-sectional/cohort/diagnostic), indication for POCUS, study population/size, ocular structure assessed, outcome measure(s), and key research findings. Descriptive data were isolated from this extracted data set and comprised author and publication year, study design, sample size, sonographer title, sonographic intervention, and a brief study description. Level of evidence (LOE) was determined for each study per the GRADE (Grading of Recommendations Assessment, Development and Evaluation) guidelines established by Sackett [6], in which increasing LOE inversely correlates with quality of evidence; the majority of included articles (75%) was LOE III, while LOE II (8.33%) and LOE IV (16.67%) were less frequent. Two independent scorers (MMC and PK) rated the quality and bias of the included articles using the MINORS scale [5].

RESULTS

The initial database search yielded 391 results, where 154 studies were identified from Scopus, 121 from MEDLINE, 99 from Web of Science, and 17 from Cochrane CENTRAL. We excluded 153 duplicate studies and screened the remaining 238 (Fig. 1). We excluded 122 studies because they were the wrong type (i.e., case reports, narrative reviews, editorials, nonprimary studies), 63 because they used a non-POCUS ultrasound modality (e.g., A-scan biometry) or lacked a measurable primary outcome, 26 because they were not conducted in emergency settings, and 3 because they were either nonhuman or cadaveric studies. A total of 24 articles encompassing 2,448 patients was included [7–30]. All included articles were published from 2013 to 2023 and represented the use of POCUS for ocular pathology in an emergency setting.

Fig. 1.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flowchart for article identification and selection. CENTRAL, Central Register of Controlled Trials; POCUS, point-of-care ultrasound.

Most sonographers were emergency medicine attending physicians (50.0%), and the others were emergency medicine residents (16.7%), emergency medicine fellows (12.5%), trained sonographers or unspecified medical staff (12.5%), radiologists (4.2%), and pediatric ophthalmologists (4.2%). All included studies utilized high-frequency linear ultrasound probes to evaluate the eye and surrounding periocular tissue (Table 1) [7–30].

Description of studies selected for review

Outcome measures and primary findings were isolated from the initially extracted data set (Table 2) [7–30]. Of the 24 included studies using POCUS for ocular assessment in an emergency setting, 18 assessed optic nerve sheath diameter (ONSD) as a primary endpoint, three assessed the posterior segment, and three grossly assessed the globe and orbit.

Outcome measures and primary findings

Of the 18 studies utilizing POCUS to evaluate ONSD as a primary endpoint, eight used sonographic intervention to detect changes in intracranial pressure (ICP)/papilledema. All eight found that POCUS-measured ONSD was accurate and precise to sensitively and specifically detect ICP changes. Of the remaining 10 articles, three used sonographic intervention to detect cerebral edema associated with hyperglycemia or diabetic ketoacidosis (DKA). One of three articles found a significant change in ONSD in patients with DKA-associated cerebral edema [25]. One study used sonographic intervention to detect linear, depressed, and lateral orbital fractures and found that POCUS was 93.7% sensitive and 96.8% specific for this use [27]. Another study used sonographic intervention to prognosticate post-cerebrovascular event mortality and found that ONSD was significantly larger in patients who succumbed to acute stroke, with a ONSD threshold of 3.99 mm or greater exhibiting 83.3% sensitivity and 59.2% specificity in predicting death secondary to acute stroke [16]. Another study used POCUS-measured ONSD to support the diagnosis and clinical picture of acute cerebrovascular disease and found that patients with acute cerebrovascular disease exhibited a significantly higher ONSD compared to control patients, with an ONSD cutoff of 5 mm displaying 98.1% sensitivity and 81.8% specificity for diagnosis of acute stroke [13]. A separate study used POCUS-measured ONSD to inform posttraumatic brain injury (post-TBI) decision-making and found it to be a useful proxy for monitoring fluctuations in ICP after TBI in limited-resource settings [29]. A different study used POCUS-measured ONSD to detect ventriculoperitoneal shunt failure and found that POCUS had a limited sensitivity of 61.1% and specificity of 22.2% for that use [7]. The final analyzed study compared the accuracy of POCUS in measuring ONSD dimensions compared to conventional computed tomography imaging and found that POCUS is efficacious in the context of ONSD measurement, with an intraclass correlation coefficient of 0.9 [8].

Of the three articles utilizing POCUS to evaluate the posterior segment as a primary endpoint, two used sonographic intervention to evaluate retinal detachment (with sensitivity ranging from 75% to 91% and specificity ranging from 94% to 96%) [10,14] and one used sonographic intervention to diagnose retinal detachment, vitreous hemorrhage, or vitreous detachment (sensitivity was 96.9%, 81.9%, and 42.5%, respectively; specificity was 88.1%, 82.3%, and 96.0%, respectively) [15]. Of the three articles utilizing POCUS to grossly evaluate the globe and orbit, two used sonographic intervention to detect general orbital pathology and trauma, with sensitivity ranging from 34.42% to 97.8% and specificity ranging from 98.7% to 99.7% [12,16], and one used sonographic intervention to detect skull fracture, with a sensitivity of 93.7% and specificity of 96.8% [27].

DISCUSSION

Ocular pathology can lead to significant disease burden [1,2], and there is recent and renewed interest and research in the utility of ocular POCUS in the emergency setting [31]. The present review is a synthesis of recently published work describing applications of ocular POCUS in the emergency setting with clearly defined and measurable study endpoints. The majority of the studies we identified focused on ONSD as a proxy for papilledema and metabolic aberrations, while a minority used ocular POCUS to assist in the diagnosis of orbital fractures or pathology of the posterior segment, orbit, and globe. In summarizing these findings, we contribute reference data to a growing body of evidence discussing the use of ocular POCUS in an emergency setting.

In recent years, ocular POCUS appears to have been especially effective in measuring ONSD as a proxy for changes in ICP and demonstrates good positive predictive value and specificity as a diagnostic tool for papilledema. This implies that POCUS is an adequate tool to emergently evaluate the effects of elevated ICP on the optic nerve, which include but are not limited to TBI, neoplasm, neurovascular compromise (e.g., cranial nerve compression or cerebrovascular ischemia), hemorrhage, and/or edema. Interestingly, emergent ocular POCUS appears to be equivocally efficacious in assessing ONSD as a novel proxy for DKA-associated cerebral edema. Emergent ocular POCUS also appears to be quite sensitive and specific for the detection of TBI [29], skull fracture [27], cerebrovascular ischemia [13,16], retinal pathology [10,14,15], and orbital trauma [12,16,27]. Notably, globe rupture is a contraindication for ocular POCUS as any pressure on the globe or adnexa in this circumstance can lead to vision-threatening reductions in intraocular pressure (hypotony) and subsequent irreversible vision loss [32]. Our findings suggest that ocular POCUS is an invaluable part of the diagnostic toolkit in managing ocular disease in the emergency setting. As such, we believe that the integration of ocular POCUS should be implemented as a standard of care workflow for diagnosis of posterior segment disease and papilledema in the emergency setting.

The use of ocular POCUS in the emergency setting has increased in recent years, enabling the evaluation of vision-threatening conditions before formal ophthalmology consultation and allowing expeditious screening of ocular pathologies requiring immediate consultation [31]. Despite the utility of ocular POCUS, some ED clinicians may defer its usage due to other pressing clinical tasks that obviate its widespread integration. To encourage the implementation of ocular POCUS into the emergency room workflow, healthcare institutions could consider the adoption of medical imaging committees to iteratively evaluate current approaches to ocular imaging. Ocular POCUS can be implemented as an initial screening tool while patients await evaluation with radiography or magnetic resonance imaging. The convenience and affordability of ocular POCUS offer benefits that should be considered in the development of clinical practice guidelines.

There are several limitations to this review. First, data on the reporting of other emergency ocular POCUS applications, such as diagnosis of full-thickness retinal detachment, were not specifically elicited. Second, our search criteria excluded nonprimary studies and studies not conducted in an ED. This restriction likely precluded a comprehensive synthesis of the known applications of emergency ocular POCUS, especially those for which there is robust empiric backing, such as diagnosis of posterior segment pathology. It may have also excluded the reporting of recently published papers describing new applications of ocular POCUS research, such as the use of POCUS-measured ONSD for neuroprognostication after resuscitation in patients undergoing cardiac arrest.

Additionally, the primary endpoints identified in the included articles differed, hindering quantitative comparison of study outcomes. This difference adds to the call for standardization of the design and reporting of future emergency ocular POCUS studies. Nonetheless, this review supports the continued development and implementation of ocular POCUS as a tool in the ED. A complete understanding of the clinical and economic implications of emergency ocular POCUS will inform the development of system-level initiatives that integrate this imaging technology to enhance patient care and clinician efficiency. Future studies should incorporate standardized implementation and reporting methods to ensure facile quantitative comparison and monitoring. In doing so, they can shed light on the true benefits and downsides of emergency ocular POCUS.

Notes

Author contributions

Conceptualization: AdS, MG, EH, SS, JCF, KD; Data curation: CDY, CKK, MMC, PK, APPB; Formal analysis: CDY, CKK, SS; Investigation: CDY, CKK, SS; Methodology: CDY, CKK, MMC, PK, APPB; Writing-original draft: CDY; Writing-review & editing: all authors. All authors read and approved the final manuscript.

Conflicts of interest

The authors have no conflicts of interest to declare.

Funding

The authors received no financial support for this study.

Data availability

Data analyzed in this study are available from the corresponding author upon reasonable request.

Supplementary materials

Supplementary Table 1.

Search terms (January 1, 2013–December 26, 2023)

ceem-24-249-supplementary-Table-1.pdf

Supplementary Table 2.

Comprehensive summary of extracted data

ceem-24-249-supplementary-Table-2.xlsx

Supplementary materials are available from https://doi.org/10.15441/ceem.24.249.

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Article information Continued

Copyright © 2024 The Korean Society of Emergency Medicine

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/).

Notes

Capsule Summary

What is already known

Prior research has established ocular point-of-care ultrasound (POCUS) as an accurate diagnostic modality for ocular trauma and diseases of the ocular fundus in the emergency setting.

What is new in the current study

This scoping review synthesizes recent evidence regarding the use of ocular POCUS and demonstrates its efficacy in detecting papilledema and, by proxy, fluctuations in intracranial pressure, supporting its integration into the emergency workflow.

Fig. 1.

Fig. 1.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flowchart for article identification and selection. CENTRAL, Central Register of Controlled Trials; POCUS, point-of-care ultrasound.

Table 1.

Description of studies selected for review

Study Study design LOE Sample size Sonographer Sonographic intervention Brief description
Hall et al. [7] (2013) Prospective cohort III 39 Pediatric emergency medicine physicians Transverse and coronal views Assessed the test characteristics of POCUS-measured ONSD as a screening tool for pediatric ventriculoperitoneal shunt failure
ONSD (14 MHz L14-5/38 CEP linear probe, Ultrasonix)
Hassen et al. [8] (2015) Retrospective case series V 61 Emergency medicine physicians Transverse view Assessed the accuracy of POCUS as a tool for measuring ONSD as compared to conventional head/neck CT scan
ONSD (7.5-10 MHz LOGIQ e linear array probe, GE Healthcare)
Komut et al. [9] (2016) Prospective cohort III 100 Radiologists Transverse and coronal views Assessed the test and receiver operating curve characteristics of POCUS in determining ICP increase in patients presenting with a suspected intracranial event
ONSD (11 and 14 MHz Aplio 500 Platinum probe, Toshiba Medical Systems)
Jacobsen et al. [10] (2016) Retrospective cohort III 109 Emergency medicine physicians Sagittal and transverse views Assessed the test characteristics of POCUS as a tool for diagnosis of retinal pathology compared to the formal diagnosis rendered by a consulting ophthalmologist
Posterior chamber and optic nerve (7.5 MHz M-Turbo linear probe, Sonosite)
Bergmann et al. [11] (2016) Cross-sectional V 108 Pediatric emergency medicine fellows Anterior transbulbar approach Evaluated mean binocular ONSD as a potential discriminatory diagnostic tool for the presence of DKA or subclinical DKA-related cerebral edema
ONSD (13-6 MHz M-Turbo linear probe, Sonosite)
Pujari et al. [12] (2018) Prospective cohort III 122 Pediatric ophthalmologists General B scan Assessed the efficacy of bedside B scan in the identification of posterior segment or orbital pathology in a pediatric population
Posterior segment and orbit (10 MHz linear probe, Sonomed)
Yuzbasioglu et al. [13] (2018) Cross-sectional V 55 Trained medical staff Sagittal and transverse views Assessed the correlation between ONSD and clinical presentation, comorbidities, CT findings, or NIHSS score in patients with cerebrovascular disease
ONSD (7.5 MHz linear probe, Mindray Biomedical)
Kim et al. [14] (2019) Prospective cohort III 115 Emergency medicine physicians Transverse and longitudinal views Assessed the test characteristics of POCUS as a tool for detection of retinal detachment compared to the formal diagnosis rendered by a consulting ophthalmologist
Posterior segment (6-13 MHz Edge linear probe, Sonosite)
Lahham et al. [15] (2019) Prospective cohort III 225 Emergency medicine residents, physician assistants, and physicians Static and kinetic images of sagittal and transverse views Assessed the test characteristics of POCUS in the diagnosis of retinal detachment, vitreous hemorrhage, and vitreous detachment compared to the formal diagnosis rendered by a consulting ophthalmologist
Posterior segment (7.5 MHz TE7 and M-Turbo linear probes, Mindray, Sonosite)
Ojaghihaghighi et al. [16] (2019) Prospective cohort III 232 Emergency medicine physicians Sagittal and transverse views Assessed the characteristics of POCUS and its interrater agreeability with orbital CT as a tool for diagnosing traumatic eye injuries
General globe (7-15 MHz M-Turbo linear probe, SonoSite)
Seyedhosseini et al. [17] (2019) Prospective cohort III 60 Emergency medicine physicians Transverse and coronal views of both eyes Assessed the utility of ONSD measured via POCUS as a prognostic tool for mortality in patients with acute stroke symptoms
ONSD (10 MHz SonoAce X8 linear probe, Madison)
Shokoohi et al. [18] (2020) Prospective Cohort III 82 Emergency medicine physicians Transverse and coronal views of both eyes Evaluated the correlation between ONSD measured via POCUS and MRI of the head for the work up and diagnosis of patients with symptoms of elevated ICP
ONSD and optic disc (13-6 MHz M-Turbo or X-Porte linear probe, Sonosite)
Mathews et al. [19] (2020) Prospective cohort III 175 Emergency medicine physicians Transverse view of both eyes Assessed the test characteristics of a POCUS-measured ONSD threshold as a proxy for elevated ICP compared to CT findings
ONSD (10 MHz)
Sik et al. [20] (2021) Prospective cohort III 43 Pediatric emergency medicine fellows Transverse view of both eyes Assessed the prognostic value of ONSD and ONSD to eyeball diameter ratios for the diagnosis of cerebral edema in children with DKA
ONSD, eyeball transverse and vertical diameters (12-4 MHz ClearVue 350 linear probe, Philips)
Wilson et al. [21] (2021) Retrospective cohort III 206 Emergency medicine residents Transverse and sagittal views Assessed the test characteristics and prognostic value of a novice-operated POCUS-measured ONSD threshold for diagnosis of papilledema
ONSD (high-frequency X-porte, Sonosite or Sparq linear probes, Philips)
Yildiz et al. [22] (2021) Prospective cohort III 82 Emergency medicine residents Transverse view Assessed the prognostic value of POCUS-measured ONSD for the monitoring of ICP changes after ischemic stroke
ONSD (5-10 MHz Titan 5000TM linear probe, Sonosite)
Kennedy et al. [23] (2021) Cross-sectional V 24 Pediatric emergency medicine fellows and physicians Ocular POCUS was performed according to the ACEP policy statement on ultrasound imaging (Z.One PRO, Mindray) Assessed the utility of ocular POCUS in the physical exam and evaluation of children with multisystem inflammatory syndrome
VS et al. [24] (2022) Prospective cohort III 69 Emergency medicine physicians Transverse view Assessed the test characteristics and prognostic value of POCUS-measured ONSD threshold for diagnosis of elevated ICP
ONSD (high-frequency M-Turbo linear probe, Sonority)
Akhtar et al. [25] (2022) Prospective comparative II 100 Third-year emergency medicine residents Transverse view Assessed the test characteristics and prognostic value of POCUS-measured ONSD threshold for diagnosis of elevated ICP as compared to gold CT and MRI
ONSD (7.55 MHz high-frequency linear probe)
Erol et al. [26] (2022) Prospective comparative II 100 Emergency medicine physicians Transverse and sagittal views Assessed the relationship between POCUS-measured ONSD and hyperglycemia
ONSD (7.5 MHz linear probe, Mindray)
Sik et al. [27] (2023) Prospective cohort III 112 Pediatric emergency medicine fellows Transverse, sagittal, and coronal views Assessed the test characteristics of POCUS-measured ONSD as a prognostic tool for diagnosis of skull fracture compared to gold standard CT imaging
ONSD and cranial integrity (L12-4 ClearVue 350 linear probe, Philips)
Kappagantu et al. [28] (2023) Prospective cohort III 125 Trained sonographers Transverse and sagittal views Assessed the test characteristics and prognostic value of POCUS-measured ONSD threshold for diagnosis of elevated ICP in a pediatric population
ONSD (7-12 MHz and L25-L38 M-Turbo linear probes, Sonosite)
Getachew et al. [29] (2023) Prospective cohort III 50 Emergency medicine residents NA Assessed the utility of POCUS-measured ONSD as a diagnostic/decision-making tool when evaluating patients with traumatic brain injury in a limited-resource setting
Uttanganakam et al. [30] (2023) Prospective cohort III 54 Trained sonographers Transverse view Assessed the utility of POCUS-measured ONSD as a guide for correction of hyponatremia
ONSD (6-13 M-Turbo linear probe, Sonosite)

LOE, level of evidence; ONSD, optic nerve sheath diameter; POCUS, point-of-care ultrasound; CT, computed tomography; ICP, intracranial pressure; DKA, diabetic ketoacidosis; NIHSS, National Institutes of Health Stroke Scale; MRI, magnetic resonance imaging; ACEP, American College of Emergency Physician; NA, not applicable.

Table 2.

Outcome measures and primary findings

Study Clinical context Outcome measure Primary finding MINORS score
Hall et al. [7] (2013) Assessed the test characteristics of POCUS-measured ONSD as a screening tool for pediatric VPS failure ONSD The mean ONSD differed significantly between encounters with (4.5±0.9 mm) and without VPS failure (5.0±0.6 mm, P=0.03). 10
However, POCUS-measured ONSD showed limited sensitivity (61.1%) and specificity (22.2%) for detecting shunt failure, rendering it an insufficient primary tool for evaluating VPS failure.
Hassen et al. [8] (2015 )a) Assessed the accuracy of POCUS as a tool for measuring ONSD as compared to conventional head/neck CT scan ONSD The difference in ONSD measurements between POCUS and CT fell within the predetermined cutoff value of 0.5 mm for the majority of cases (P<0.0001). 19
POCUS is an accurate tool for measuring ONSD and serves as a reliable complement to the standard CT technique.
Komut et al. [9] (2016)a) Assessed the test and receiver operating curve characteristics of POCUS in determining ICP increase in patients presenting with a suspected intracranial event ONSD ONSD was markedly higher in patients with intracranial pathology compared to those with normal intracranial findings on CT (P<0.05). 12
POCUS-measured ONSD is a valuable tool for assessing ICP elevation and severity of intracranial events.
Jacobsen et al. [10] (2016) Assessed the test characteristics of POCUS as a tool for diagnosis of retinal pathology compared to the formal diagnosis rendered by a consulting ophthalmologist Diagnosis of RD POCUS showed a sensitivity of 91% in detecting RD and a specificity of 96%. 18
Thus, POCUS accurately aids in the diagnosis of RD in the ED.
Bergmann et al. [11] (2016) Evaluated mean binocular ONSD as a potential discriminatory diagnostic tool for the presence of DKA or subclinical DKA-related cerebral edema Mean binocular ONSD The between-group difference in mean ONSD among control, non-DKA, and DKA patients was not significant (P=0.79). 16
POCUS-measured ONSD measurements showed no significant variation between patients with signs and symptoms of DKA and those without.
Pujari et al. [12] (2018) Assessed the efficacy of bedside B scan in the identification of posterior segment or orbital pathology in a pediatric population Diagnosis of ocular pathology POCUS effectively identified ocular pathologies, including posttraumatic globe injuries (65.57%) and nontraumatic pathology (34.42%) such as corneal ulcer, retinoblastoma, and endophthalmitis. 10
Yuzbasioglu et al. [13] (2018)a) Assessed the correlation between ONSD and clinical presentation, comorbidities, CT findings, or NIHSS score in patients with cerebrovascular disease ONSD The experimental group exhibited a significantly higher ONSD compared to the control group, with median values of 5.7 and 3.6 mm, respectively (P<0.05). 14
POCUS-measured ONSD can be used to support the diagnosis and evaluation of patients with acute stroke.
Kim et al. [14] (2019) Assessed the test characteristics of POCUS as a tool for detection of RD compared to the formal diagnosis rendered by a consulting ophthalmologist Diagnosis of RD The sensitivity and specificity of POCUS for detecting RD were 75% and 94%, respectively. 18
Although emergency physicians showed high specificity in performing POCUS for RD, a negative POCUS scan lacks the sensitivity needed to reliably rule out RD in patients with new-onset flashes or floaters.
Lahham et al. [15] (2019) Assessed the test characteristics of POCUS in the diagnosis of RD, vitreous hemorrhage, and vitreous detachment compared to the formal diagnosis rendered by a consulting ophthalmologist Diagnosis of RD, vitreous hemorrhage, or vitreous detachment POCUS demonstrated high sensitivity for RD (96.9%) and vitreous hemorrhage (81.9%), while showing lower sensitivity for vitreous detachment (42.5%). 20
Specificity was consistently high for all conditions: RD, 88.1%; vitreous hemorrhage, 82.3%; vitreous detachment, 96.0%.
Ojaghihaghighi et al. [16] (2019) Assessed the test characteristics of POCUS and its interrater agreeability with orbital CT as a tool for diagnosing traumatic eye injuries Diagnosis of traumatic ocular injury Compared to CT imaging and complete bedside ocular examination by an ophthalmologist, POCUS demonstrated the following specificity and sensitivity for various diagnoses: lens dislocation (specificity, 99.4%; sensitivity, 96.8%), retrobulbar hematoma (specificity, 99.7%; sensitivity, 95.7%), and vitreous hemorrhage (specificity, 98.7%; sensitivity, 97.8%). 20
Seyedhosseini et al. [17] (2019)a) Assessed the utility of ONSD measured via POCUS as a prognostic tool for mortality in patients with acute stroke symptoms ONSD The average ONSD was 4.40±0.64 mm in deceased patients and 3.83±0.56 mm in living patients (P=0.036). This suggests that POCUS-measured ONSD in acute stroke may serve as a useful predictor of mortality. 10
Shokoohi et al. [18] (2020) Evaluated the correlation between ONSD measured via POCUS and MRI of the head for the workup and diagnosis of patients with symptoms of elevated ICP ONSD There was no significant correlation between ultrasound measurements (axial or coronal) and MRI measurements, and no ultrasound findings reliably identified subjects with idiopathic intracranial hypertension. This suggests that ultrasound assessments of ONSD and OND may not be reliable indicators of increased ICP. 19
Mathews et al. [19] (2020) Assessed the test characteristics of a POCUS-measured ONSD threshold as a proxy for elevated ICP compared to CT findings ONSD Compared to gold standard CT findings, POCUS-measured ONSD displayed a sensitivity of 87.5% and specificity of 94.1%. 21
The resulting positive predictive value was 87.5% and the negative predictive value was 94.1%.
Sik et al. [20] (2021)a) Assessed the prognostic value of ONSD and ONSD/eyeball diameter ratios for the diagnosis of cerebral edema in children with DKA ONSD, ONSD/ETD ratio, and ONSD/EVD ratio Baseline measurements of ONSD, ONSD/ETD ratio, and ONSD/EVD ratio were higher in the severe group than in the mild-moderate group (P=0.037, P=0.020, P=0.045, respectively), with no difference between mild and moderate groups. 12
Following therapy, all ONSD measurements and ratios significantly decreased compared to baseline (P<0.001), suggesting that POCUS holds promise as a valuable tool for evaluating children with DKA.
Wilson et al. [21] (2021) Assessed the test characteristics and prognostic value of a novice-operated POCUS-measured ONSD threshold for diagnosis of papilledema ONSD POCUS-measured ONSD demonstrated a sensitivity of 46.9% and specificity of 87.0% for diagnosing papilledema. 16
Sonographic measurement of ONSD by emergency physicians exhibits low sensitivity but high specificity compared to ophthalmologist-conducted fundoscopy in detecting papilledema.
Yildiz et al. [22] (2021)a) Assessed the prognostic value of POCUS-measured ONSD for the monitoring of ICP changes after ischemic stroke ONSD On the third day of hospitalization, ONSD was significantly larger than on the first day (P<0.05), and on the fifth day, it showed a nonsignificant increase compared to the first day (P>0.05). 12
ONSD serves as an early diagnostic tool for increased ICP and offers early prognostic value.
Kennedy et al. [23] (2021) Assessed the utility of ocular POCUS in the physical exam and evaluation of children with multisystem inflammatory syndrome ONSD POCUS was a useful adjunct to reveal various findings, including impaired cardiac contractility, intraperitoneal free fluid, and optic nerve abnormalities in patients with multisystem inflammatory syndrome. 10
VS et al. [24] (2022) Assessed the test characteristics and prognostic value of POCUS-measured ONSD threshold for diagnosis of elevated ICP ONSD In patients with features of raised ICP in brain CT, the average ONSD was 5.4 mm, compared to 4.4 mm in those without such features. NA
Using a cutoff of 5 mm, POCUS-measured ONSD demonstrated 88% sensitivity, 100% specificity, a positive predictive value of 100%, and an overall accuracy of 91.3% for diagnosing elevated ICP.
Akhtar et al. [25] (2022) Assessed the test characteristics and prognostic value of POCUS-measured ONSD threshold for diagnosis of elevated ICP as compared to gold CT and MRI ONSD With a cutoff ONSD value of 6.3 mm, POCUS demonstrated 100% sensitivity, 89.2% specificity, 83.3% positive predictive value, 100% negative predictive value, and 93% diagnostic accuracy for detecting raised ICP compared to brain CT/MRI. 18
Erol et al. [26] (2022) Assessed the relationship between POCUS-measured ONSD and hyperglycemia ONSD Before treatment for hyperglycemia, the ONSD was 4.5±0.4 mm in patients and 4.4±0.5 mm in healthy controls, showing no statistical difference between both groups (P=0.162). 16
Following treatment, ONSD increased by 0.6±0.4 mm in patients, with no significant difference observed between subgroups of patients with DKA or hyperosmolar hyperglycemic syndrome and those with isolated hyperglycemia (P=0.294).
Sik et al. [27] (2023) Assessed the test characteristics of POCUS-measured ONSD as a prognostic tool for diagnosis of skull fracture compared to gold standard CT imaging ONSD, diagnosis of skull fracture POCUS demonstrated sensitivity of 93.7% and specificity of 96.8% for detecting skull fractures, with a positive predictive value of 95.7% and a negative predictive value of 95.3%. NA
High agreement (κ=0.90±0.04) was observed between POCUS and CT in identifying skull fractures.
Kappagantu et al. [28] (2023) Assessed the test characteristics and prognostic value of POCUS-measured ONSD threshold for diagnosis of elevated ICP in a pediatric population ONSD The mean ONSD was 5.5±0.6 mm in the case group and 4.9±0.5 mm in the control group. 18
A cutoff ONSD of ≥4.5 mm had a sensitivity of 97.67% and specificity of 10.98%, while ≥5.0 mm showed a sensitivity of 86.05% and specificity of 71.95% for detecting raised ICP.
Getachew et al. [29] (2023) Assessed the utility of POCUS-measured ONSD as a diagnostic/decision-making tool when evaluating patients with TBI in a limited-resource setting ONSD In two patients with TBI showing a declining clinical course, repeat POCUS-measured ONSD increased, suggesting that ONSD is a useful adjunct tool in the evaluation of TBI in limited-resource settings. 8
Uttanganakam et al. [30] (2023) Assessed the utility of POCUS-measured ONSD as a guide for correction of hyponatremia ONSD There was a statistically significant difference in ONSD before and after the treatment of hyponatremia. 15
However, POCUS-measured ONSD was not able to predict the sodium level measured both by laboratory and point-of-care methods.

MINORS, Methodological Index for Nonrandomized Studies; POCUS, point-of-care ultrasound; ONSD, optic nerve sheath diameter; VPS, ventriculoperitoneal shunt; CT, computed tomography; ICP, intracranial pressure; RD, retinal detachment; ED, emergency department; DKA, diabetic ketoacidosis; NIHSS, National Institutes of Health Stroke Scale; MRI, magnetic resonance imaging; OND, optic nerve diameter; ETD, eyeball transverse diameter; EVD, eyeball vertical diameter; NA, not available; TBI, traumatic brain injury.

a)

Statistically significant findings.