Investigating Optic Nerve Sheath Diameter in Prone Position Spinal Surgery Patients: A Pilot Study.

Purpose: This study aimed to evaluate the effect of intraoperative positioning and ocular immobility on the amount of cerebrospinal fluid around the optic nerve in patients undergoing prone spinal surgery by measuring the optic nerve sheath diameter (ONSD) using ultrasound. Methods: Consecutive participants (n = 15 patients, 30 eyes) were scanned preoperatively, intraoperatively approximately 20 minutes before the end of the surgery, and postoperatively in the post-anesthesia care unit at least 10 min after the completion of the surgery at one academic hospital. Results: On average, patients who underwent prone spinal surgery had a 21% increase in ONSD intraoperatively, with a positive time-dependent relationship with the overall length of surgery (P < 0.001). ONSDs postoperatively returned to baseline and were not significantly different from preoperative measurements. Conclusion: Our findings suggest pooling and inadequate clearance of perioptic cerebrospinal fluid during prone spinal surgery that improves following termination of the procedure and return of the patient to an upright position.

Ocular Ultrasound in the Diagnosis of Optic Neuropathies: A Review of the Literature.

BACKGROUND: Optic neuropathies represent one of the most frequent causes of vision loss, and they can manifest alone or in conjunction with neurological or systemic symptoms and signs. In recent years, the diagnostic techniques used to detect optic neuropathies have significantly improved, facilitating diagnosis and improving treatment. Among these, ocular ultrasound has assumed a fundamental role, although with conflicting results in the published scientific literature. For this reason, the aim of this review is to analyze the role of ocular ultrasound in the precise and targeted diagnosis of optic neuropathies to better understand the presumed potential of this precious diagnostic tool in the management of these ocular and neurological disorders. METHODS: We carried out a search on PubMed and Scopus utilizing terms related to optic neuropathies and ocular ultrasound, including only relevant English full-length research articles, case reports, or case series. RESULTS: Most of the papers published in the scientific literature use only the B-scan ultrasound technique without considering the more precise and objective standardized A-scan technique that allows for performing more accurate diagnostic tests, such as the "30-degree test" and the "optic nerve exercise test". CONCLUSIONS: Future clinical trials and research on optic neuropathies should also consider the use of the standardized A-scan technique in order to compare clinical findings not only with B-scan ultrasonography but also with other noninvasive procedures that could be helpful in reaching the correct diagnosis.

Ophthalmic findings and reference values for selected ocular parameters in whooping cranes (Grus americana) and Mississippi sandhill cranes (Grus canadensis pulla).

OBJECTIVE: To establish baseline ophthalmic parameters for an endangered, semi-wild population of healthy whooping cranes (Grus americana) (WHCR) and Mississippi sandhill cranes (Grus canadensis pulla) (SACR). ANIMALS STUDIED: Eighteen WHCR and 16 SACR. PROCEDURES: Ophthalmic examination was performed by a single observer, followed by conjunctival swab collection for aerobic bacterial culture and measurement of tear production (phenol red thread test, PRTT) and corneal diameter (CD) as tolerated. Measurement of the axial globe (AG) length, anterior chamber (AC) depth, lens thickness, vitreous chamber (VC) depth, and pecten length was performed via ocular ultrasound (OUS) as tolerated. RESULTS: Eyelid cicatrization (n = 1 WHCR), keratitis (n = 2 WHCR), incipient cataracts (n = 1 WHCR, n = 4 SACR), and uveal cysts (n = 1 SACR) were identified. Twenty-one bacterial species were cultured from SACR, while 18 bacterial species were cultured from WHCR. SACR under 6 months old had increased PRTT values compared to older SACR (p = .0432). AG length and VC depth of male WHCR were greater than in female WHCR (p = .0045 and p = .0008, respectively). WHCR less than 6 months old had greater AC depth and lens thickness than WHCR over 6 months (p < .001 and p = .0013, respectively). SACR less than 6 months old had greater AC depth and lens thickness than WHCR over 6 months (p < .0001 and p < .0001, respectively). CONCLUSIONS: WHCR and SACR are amenable to complete ophthalmic examination. Age-related differences in PRTT in SACR, sexual dimorphism in WHCR, and age-related differences in AC depth and lens thickness in WHCR and SACR were identified.

Pseudo-pigmented choroidal schwannoma with extraocular extension in an elderly patient.

Purpose: To describe a rare case of clinically pigmented choroidal schwannoma with extraocular extension in an elderly patient. Observations: We report a case of a 79-year-old Black male who presented with a clinically pigmented, juxtapapillary choroidal tumor with concern for extraocular extension on standardized ocular echography. The lesion was concerning for choroidal melanoma with extraocular extension. He had no history of cancer or known genetic disease. After an extensive discussion of management options, he underwent enucleation of the left eye. Histopathology of the tumor showed non-pigmented cells with bland, spindle-shaped nuclei and areas of Antoni A pattern along with immunostaining consistent with choroidal schwannoma with extraocular extension. Conclusion: Choroidal schwannoma can mimic choroidal melanoma and can have a clinically pigmented appearance particularly in darkly complected individuals. This case highlights the importance of including choroidal schwannoma on the differential diagnosis for choroidal neoplasms, particularly in populations of individuals in whom melanoma is less common. Though more common in younger patients, choroidal schwannoma can present in elderly patients.

Diagnostic Accuracy of Optic Nerve Sheath Diameter Using Ultrasonography for Raised Intracranial Pressure in Pediatric Patients - A Systematic Review and Meta-Analysis.

PURPOSE: Detecting increased intracranial pressure early in pediatric patients is essential, as early initiation of therapy prevents morbidity and mortality. The objective of this study was to determine the diagnostic accuracy of the optic nerve sheath diameter (ONSD) measured via ultrasound for the prediction of increased intracranial pressure. METHODS: Four databases, namely, PubMed, EMBASE, Scopus, and CINAHL, were searched for this systematic review and meta-analysis. The study's predefined inclusion criteria considered diagnostic accuracy, cross-sectional, prospective observational, and retrospective studies with a focus on children with elevated intracranial pressure from causes such as traumatic brain injury and cerebral edema, the diagnostic accuracy of the optic nerve sheath diameter measured using ultrasound was assessed. The primary outcome measures included sensitivity and specificity. The study included invasive monitoring (external ventricular drain) and noninvasive measures as the gold standards for increased intracranial pressure. Two authors extracted and reviewed the data. Baseline data, outcome measures, and diagnostic accuracy data were extracted. RESULTS: Twenty-five studies with 1591 patients and 3143 ONSD measurements via ultrasound were analyzed. The pooled sensitivity and specificity of the ONSD measured via ultrasound for the prediction of increased intracranial pressure were 92% (86%-96%) and 89% (77%-96%), respectively. The pooled positive and negative likelihood ratios were 8.6 and 0.08, respectively. CONCLUSION AND RELEVANCE: Optic nerve ultrasonography stands out as a precise and valuable diagnostic tool applicable across diverse patient populations and clinical scenarios. We recommend routine ocular ultrasound for optic nerve sheath diameter measurement in pediatric patients to increase the accuracy of diagnosing increased intracranial pressure.

Characterization of Ocular Sonography Findings and their Relationship to Clinical Features from a South Indian Cohort of Idiopathic Intracranial Hypertension.

Background: Idiopathic intracranial hypertension (IIH) typically manifests with headache, accompanied by papilledema and visual loss, and has a higher prevalence in females. In recent years, ocular sonography, particularly, measurement of optic nerve sheath diameter (ONSD), is being investigated for diagnosis of IIH. Methods: A total of 35 patients over the age of 18 years, fulfilling the modified Dandy's criteria for diagnosis of IIH were included. Patients underwent assessment with magnetic resonance imaging, lumbar puncture, and ocular sonography to measure ONSD and ocular arterial indices. Results: The mean ONSD values (in centimeters) in the right eye of patients with IIH was 0.57 ± 0.13, while it was 0.48 ± 0.03 in controls. In the left eye, the mean ONSD value (cm) was 0.59 ± 0.13 in patients with IIH and 0.48 ± 0.03 in controls. ONSD was significantly higher in cases compared to controls (P < 0.001, Welch test). Pulsatility index of the central retinal artery was significantly higher in cases compared to controls (P < 0.001, Welch test). Resistance index of the ophthalmic artery was statistically significant (P < 0.005, Welch test). Receiver operating characteristic curve analysis revealed a cutoff value of 5.1 mm on the right side and 5 mm on the left side had a sensitivity and specificity of more than 80% for IIH diagnosis. Conclusion: Our study provides insights into the utility of optic nerve sheath measurements and arterial indices in the diagnosis of IIH in a South Indian cohort. Further research is needed to fully understand the longitudinal relationship of these parameters and treatment outcomes in IIH.

Terson Syndrome Diagnosed by Ocular Point of Care Ultrasound on the Medical Floor.

In acute care environments, accurately assessing complications of intracranial pathology can be challenging. Ocular complications in acute intracranial disease are not consistently evaluated despite their high morbidity. We report on a case of monocular diplopia in a 63-year-old man with subacute traumatic brain injury with localized subarachnoid hemorrhage. Ocular point of care ultrasound (POCUS) identified features of vitreous hemorrhage in one globe, leading to a diagnosis of Terson syndrome and a timely referral to ophthalmology. This finding was made on the medical floor days after the initial presentation during rehabilitation when ophthalmoscopy was not possible, and vitreous hemorrhage had not been identified on presentation. Terson syndrome is a seldom discussed but important complication of intracranial hemorrhage generally associated with poor patient outcomes. Ocular POCUS can provide a useful alternative in assessing ocular complications of acute intracranial disease on the medical floor, particularly when the practicalities of performing ophthalmoscopy are challenged.

Assessing the Usefulness of Ultrasonography for the Diagnosis and Evaluation of Intra-Orbital Lesions in Pediatric Patients: A Retrospective Analysis.

OBJECTIVES: To assess the usefulness of ultrasonography in the diagnosis and evaluation of extraocular intra-orbital lesions in pediatric patients. METHODS: Twenty-three pediatric patients with intra-orbital lesions who underwent both ultrasound and computed tomography/magnetic resonance imaging (CT/MRI) were included. The following parameters were evaluated using ultrasound: 1) lesion detection rate (presence or absence of lesions), 2) lesion characteristics, 3) lesion location (extraconal or intraconal), and 4) the lesion longest linear dimensions, and these were compared using Fisher's exact test and Mann-Whitney U test. RESULTS: Two lesions could not be detected using ultrasound; in the other 21 cases, the lesion characteristics diagnosed by ultrasound were correct. Diagnostic accuracy of detection and characteristics assessment using ultrasound were 91.3% and 91.3%, respectively. The lesion location was not significantly different between the two groups (intraconal/extraconal in those detected using ultrasound versus those in the absence on ultrasound = 7/14 versus 0/2, P > .999); however, in two cases that were not detected on ultrasound, the lesions were located at extraconal. Lesions that were small in longest linear dimensions on CT/MRI were not detected using ultrasound (the longest linear dimensions in lesions detected using ultrasound versus that in the absence of ultrasound: 29.5 ± 8.2 [range, 13-46] versus 10 and 11 mm, P = .043). CONCLUSIONS: Ultrasonography proved to be useful for visualizing and evaluating intra-orbital lesions except for lesions that were relatively small in size. Therefore, although ultrasound could not detect lesions located behind bone and bone invasion, it could be used for diagnosing and selecting treatment strategies for intra-orbital lesions.

A Novel Method for Prediction of Raised Intracranial Pressure Through Automated ONSD and ETD Ratio Measurement From Ocular Ultrasound.

The paper presents a novel framework for the prediction of the raised Intracranial Pressure (ICP) from ocular ultrasound images of traumatic patients through automated measurement of Optic Nerve Sheath Diameter (ONSD) and Eyeball Transverse Diameter (ETD). The measurement of ONSD using an ocular ultrasound scan is non-invasive and correlates with the raised ICP. However, the existing studies suggested that the ONSD value alone is insufficient to indicate the ICP condition. Since the ONSD and ETD values may vary among patients belonging to different ethnicity/origins, there is a need for developing an independent global biomarker for predicting raised ICP condition. The proposed work develops an automated framework for the prediction of raised ICP by developing algorithms for the automated measurement of ONSD and ETD values. It is established that the ONSD and ETD ratio (OER) is a potential biomarker for ICP prediction independent of ethnicity and origin. The OER threshold value is determined by performing statistical analysis on the data of 57 trauma patients obtained from the AIIMS, New Delhi. The automated OER is computed and compared with the conventionally measured ICP by determining suitable correlation coefficients. It is found that there is a significant correlation of OER with ICP (r = .81, p ≤ .01), whereas the correlation of ONSD alone with ICP is relatively less (r = .69, p = .004). These correlation values indicate that OER is a better parameter for the prediction of ICP. Further, the threshold value of OER is found to be 0.21 for predicting raised ICP conditions in this study. Scatter plot and Heat map analysis of OER and corresponding ICP reveal that patients with OER ≥ 0.21, have ICP in the range of 17 to 35 mm Hg. In the data available for this research work, OER ranges from 0.17 to 0.35.

The Use of POCUS-Obtained Optic Nerve Sheath Diameter in Intracerebral Hemorrhage.

Background: Intracerebral hemorrhage (ICH) is associated with high morbidity and mortality. ICH causes increased intracranial pressure (ICP), leading to brain herniation as the disease progresses. Neurological physical exam and monitoring of the disease progression can be challenging due to the impaired consciousness and routine clinical management in this patient population. Given the continuity of the intracranial cavity with the optic nerve subarachnoid space, an increased ICH leads to distension of the optic nerve sheath. We herein examined the correlation between the ICH volume and the optic nerve sheath diameter (ONSD) measured by point of care ultrasound (POCUS). Methods: Patients with ICH diagnosed with a head computed tomography (CT) scan were prospectively enrolled in this study. A portable ultrasound was used to measure the (ONSD); the volume of ICH hematoma, the Acute Physiology And Chronic Health Evaluation IV score, and the Intracerebral Hemorrhage score were collected. A Spearman rank correlation coefficient test was used to assess the relationship between continuous variables. A Wilcoxon rank sum test was used to assess differences in continuous variables between two groups. A p-value less than 0.05 was deemed as statistically significant. Results: A total of 28 subjects were enrolled. A moderate positive correlation was detected between hemorrhage volume and the average ONSD (correlation = 0.4214, p = 0.0255). A weak positive correlation was detected between average ONSD and APACHE IV (correlation = 0.2347, p = 0.2294). A weak moderate positive correlation was detected between average ONSD and ICH score (correlation = 0.1160, p = 0.5566). Conclusions: In this study we demonstrate that ONSD is moderately correlated with hematoma size. A potential application may include serial measurements of the ONSD with ultrasound. This may offer a quick, non-invasive technique that can be used in an intracerebral hemorrhage to monitor the stability or expansion of a hematoma indirectly, and potentially catch a catastrophic event like cerebral herniation.

Asteroid Hyalosis: A Mimicker of Vitreous Hemorrhage on Point of Care Ultrasound: A Case Report.

Ocular point of care ultrasound (POCUS) can help make timely recognition of multiple emergent ocular conditions and differentiate these from more benign conditions. While asteroid hyalosis (AH) is benign, it can easily mimic the more potentially serious vitreous hemorrhage on ocular POCUS, as both consist of numerous echogenic opacities within the vitreous with a classic "washing machine" appearance with eye movement. However, asteroid hyalosis particles tend to be more discrete, hyperechoic, scintillating, and seen throughout the vitreous. Knowledge of this mimic and ability to recognize the subtle sonographic differences can help differentiate these disease processes, which can influence management and potentially disposition.

Development and evaluation of a point-of-care ocular ultrasound curriculum for medical students - a proof-of-concept study.

BACKGROUND: Point-of-care Ocular Ultrasound (POCOUS) has gained importance in emergency medicine and intensive care in recent years. This work aimed to establish and evaluate a dedicated ultrasound education program for learning POCOUS-specific skills during medical studies at a university hospital. METHODS: The blended learning-based program (6 teaching units) based on recent scientific publications and recommendations was developed for students in the clinical part of their medical studies. Experts and trainers consisted of physicians from the Ear-Nose-Throat, radiology, ophthalmology and neurology specialties as well as university educational specialists. Lecture notes containing digital video links for preparation was produced as teaching material. In total, 33 students participated in the study. The education program, including the teaching materials, motivation and subjective gain in competency, was evaluated with the aid of a questionnaire (7-point Likert response format). Objective learning success was assessed on the basis of pre- and post-tests. These covered the skill areas: "anatomical basics", "ultrasound basics", "understanding of cross-sectional images", "normal findings" and "pathology recognition". RESULTS: In the objective assessment of image interpretation, the participants improved significantly (p < 0.001) from pre- to post-test with a large effect size (Cohen's d = 1.78, effect size r = 0.66). The evaluations revealed a high level of satisfaction with the course concept, teaching materials and the tutors. In addition, a high level of motivation was recorded in relation to continuing to study "ultrasound diagnostics" and "ophthalmologic diseases". A significant (p < 0.01) positive gain was also achieved in terms of the subjective assessment of competency. This covers areas such as expertise, sonographic anatomy and performing a POCOUS examination as well as recognizing retinal detachment, globe perforation and increased optic nerve sheath diameter. CONCLUSION: The results of this feasibility study show that medical students accept and support a POCOUS-specific education program and are able to develop a higher objective and subjective level of competency. Future transfer to other sites and larger groups of participants seems feasible.

Evaluation of commercially available point-of-care ultrasound for automated optic nerve sheath measurement.

BACKGROUND: Measurement of the optic nerve sheath diameter (ONSD) via ultrasonography has been proposed as a non-invasive metric of intracranial pressure that may be employed during in-field patient triage. However, first responders are not typically trained to conduct sonographic exams and/or do not have access to an expensive ultrasound device. Therefore, for successful deployment of ONSD measurement in-field, we believe that first responders must have access to low-cost, portable ultrasound and be assisted by artificial intelligence (AI) systems that can automatically interpret the optic nerve sheath ultrasound scan. We examine the suitability of five commercially available, low-cost, portable ultrasound devices that can be combined with future artificial intelligence algorithms to reduce the training required for and cost of in-field optic nerve sheath diameter measurement. This paper is focused on the quality of the images generated by these low-cost probes. We report results of a clinician preference survey and compare with a lab analysis of three quantitative image quality metrics across devices. We also examine the suitability of the devices in a hypothetical far-forward deployment using operators unskilled in ultrasound, with the assumption of a future onboard AI video interpreter. RESULTS: We find statistically significant differences in clinician ranking of the devices in the following categories: "Image Quality", "Ease of Acquisition", "Software", and "Overall ONSD". We show differences in signal-to-noise ratio, generalized contrast-to-noise ratio, point-spread function across the devices. These differences in image quality result in a statistically significant difference in manual ONSD measurement. Finally, we show that sufficiently wide transducers can capture the optic nerve sheath during blind (no visible B-mode) scans performed by operators unskilled in sonography. CONCLUSIONS: Ultrasound of the optic nerve sheath has the potential to be a convenient, non-invasive, point-of-injury or triage measure for elevated intracranial pressure in cases of traumatic brain injury. When transducer width is sufficient, briefly trained operators may obtain video sequences of the optic nerve sheath without guidance. This data suggest that unskilled operators are able to achieve the images needed for AI interpretation. However, we also show that image quality differences between ultrasound probes may influence manual ONSD measurements.

Ultrasound detected increase in optic disk height to identify elevated intracranial pressure: a systematic review.

BACKGROUND: Elevated intracranial pressure (eICP) is a serious medical emergency that requires prompt identification and monitoring. The current gold standards of eICP detection require patient transportation, radiation, and can be invasive. Ocular ultrasound has emerged as a rapid, non-invasive, bedside tool to measure correlates of eICP. This systematic review seeks to explore the utility of ultrasound detected optic disc elevation (ODE) as an ultrasonographic finding of eICP and to study its sensitivity and specificity as a marker of eICP. METHODS: This systematic review followed the preferred reporting items for systematic reviews and meta-analyses guidelines. We systematically searched PubMed, EMBASE, and Cochrane Central for English articles published before April 2023; yielding 1,919 total citations. After eliminating duplicates, and screening the records, we identified 29 articles that addressed ultrasonographically detected ODE. RESULTS: The 29 articles included a total of 1249 adult and pediatric participants. In patients with papilledema, the mean ODE ranged between 0.6 mm and 1.2 mm. Proposed cutoff values for ODE ranged between 0.3 mm and 1 mm. The majority of studies reported a sensitivity between 70 and 90%, and specificity ranged from 69 to 100%, with a majority of studies reporting a specificity of 100%. CONCLUSIONS: ODE and ultrasonographic characteristics of the optic disc may aid in differentiating papilledema from other conditions. Further research on ODE elevation and its correlation with other ultrasonographic signs is warranted as a means to increase the diagnostic accuracy of ultrasound in the setting of eICP.

Ultrasonography in neurology: A comprehensive analysis and review.

Neurologists in both the inpatient and outpatient settings are increasingly using ultrasound to diagnose and manage common neurological diseases. Advantages include cost-effectiveness, the lack of exposure to ionizing radiation, and the ability to perform at the bedside to provide real-time data. There is a growing body of literature that supports using ultrasonography to improve diagnostic accuracy and aid in performing procedures. Despite the increasing utilization of this imaging modality in medicine, there has been no comprehensive review of the clinical applications of ultrasound in the field of neurology. We discuss the current uses and limitations of ultrasound for various neurological conditions. We review the role for ultrasound in commonly performed neurologic procedures including lumbar puncture, botulinum toxin injections, nerve blocks, and trigger point injections. We specifically discuss the technique for ultrasound-assisted lumbar puncture and occipital nerve block as these are commonly performed. We then focus on the utility of ultrasound in the diagnosis of neurologic conditions. This includes neuromuscular diseases such as motor neuron disorders, focal neuropathies, and muscular dystrophy as well as vascular conditions such as stroke and vasospasm in subarachnoid hemorrhage. We also address ultrasound's use in critically ill patients to aid in identifying increased intracranial pressure, hemodynamics, and arterial and/or venous catheterization. Finally, we address the importance of standardized ultrasound curricula in trainee education and make recommendations for the future directions of research and competency guidelines within our specialty.

Using tele-ultrasound to teach medical students: A randomised control equivalence study.

Objectives: Undergraduate ultrasound education is becoming increasingly important, but its expansion is limited by time, space and the availability of trained faculty. In order to validate an alternative and more accessible teaching model, our aim was to assess whether combining teleguidance and peer-assisted learning to teach ultrasound is as effective as traditional in-person methods. Methods: Peer instructors taught 47 second-year medical students ocular ultrasound via either teleguidance or traditional in-person methods. Proficiency was assessed using a multiple-choice knowledge test and objective structured clinical examination (OSCE). Confidence, overall experience, and experience with a peer instructor were measured using a 5-point Likert scale. Two one-sided t-tests were used to measure equivalency between the two groups. The null hypothesis that the two groups were not different was rejected when P < 0.05. Results: The teleguidance group performed as well as the traditional in-person group in terms of knowledge change, confidence change, OSCE time and OSCE score (p = 0.011, p = 0.006, p = 0.005 and  = 0.004, respectively, indicating the two groups are statistically equivalent). The teleguidance group rated the experience highly overall (4.06/5), but less than the traditional group (4.47/5; P = 0.448, indicating statistical difference). Peer instruction was rated 4.35/5 overall. Conclusion: Peer-instructed teleguidance was equivalent to in-person instruction with respect to knowledge change, confidence gain and OSCE performance in basic ocular ultrasound.

Point-of-Care Ultrasound: A Moving Picture Is Worth a Thousand Tests.

The effective utilization of point-of-care ultrasound may decrease the utilization of conventional diagnostic modalities. This review describes the various pathologies that can be effectively and rapidly identified with point-of-care cardiac, lung, abdominal, vascular airway, and ocular ultrasonography.

The Association Between Hyponatremia and Optic Nerve Sheath Diameter: A Prospective Study.

Background Hyponatremia is a common electrolyte balance disorder. It may result in brain edema and increased intracranial pressure (ICP). Optic nerve sheath diameter (ONSD) measurement remains an increasingly sought-after method in many situations associated with ICP elevations. The aim of our study was to investigate the relationship between the change of ONSD before and after hypertonic saline (3% sodium chloride) treatment and the clinical improvement with increased sodium levels in patients with symptomatic hyponatremia who presented to the emergency department. Methodology This study was conducted in the emergency department of a tertiary hospital, according to the design of a prospective, self-controlled, non-randomized trial study. Determined by power analysis, 60 patients were included in the study. The statistical analysis of the continuous data was performed using the means, standard deviations, and minimum and maximum values of the feature values. The frequency and percentage values were used to define categorical variables. The mean difference comparison of pre-and post-treatment measurements was evaluated by paired t-test. P<0.05 was considered to be significant. Results The measurement parameters' differences before and after hypertonic saline treatment were evaluated. While the mean of the right eye ONSD was 5.27±0.22 mm before treatment, it declined substantially to 4.52±0.24 mm after treatment (p<0.001). It was also found that the left eye ONSD was 5.26±0.23 mm before the treatment and declined to 4.53±0.24 mm after the treatment (p<0.001). In addition, the mean of the overall ONSD was 5.26±0.23 mm before treatment and 4.52±0.24 mm after treatment (p<0.001). Conclusions Ultrasonic measurement of ONSD can be used to monitor the clinical improvement of patients receiving hypertonic saline therapy for symptomatic hyponatremia.