Mean Optic Nerve Diameter Research Articles

Pediatric optic nerve and globe measurements on magnetic resonance imaging: establishing norms for children.

Normal optic nerve diameter (OND) and optic nerve sheath diameter (ONSD) may be beneficial for describing optic nerve pathway abnormality reflecting increased intracranial pressure. Nonetheless, magnetic resonance imaging (MRI) measurement of the normal ONSD range and its associations with clinical factors and eyeball transverse diameter (ETD) are not well established in children. To establish normal OND, ONSD, ETD, and OND/ONSD and ONSD/ETD measurements in children and their associations with age and sex. We evaluated and analyzed 336 brain MRI studies of children aged 0.5 months to 18 years. We measured a total of 672 optic nerves. The OND and ONSD were measured 1 cm anterior to the optic foramina and 3 mm behind the optic disc on an axial T2 sequence. The mean OND 3 mm and 1 cm, ONSD 3 mm and 1 cm, and ETD were 0.23 ± 0.05 mm and 0.16 ± 0.04 mm, 0.53 ± 0.08 mm and 0.38 ± 0.06 mm, and 2.3 ± 0.13, respectively. Only ONSD 1 cm was independent of age (P = 0.247). ONSD 3 mm and ETD were significantly wider in boys compared to girls and significantly influenced by age (both P < 0.001). Age at scan and ETD were significantly correlated (P < 0.001). We established MRI-based OND, ONSD, ETD, and ONSD/ETD and OND/ONSD ratio normative values in children, which can be helpful in pediatric populations with disease.

Transorbital Sonography in the Evaluation of the Optic Nerve and Optic Nerve Sheath Diameter Considering Specific Demographic Features

Transorbital sonography is a reliable method for non-invasive assessment of optic nerve diameter (OND) and optic nerve sheath diameter (ONSD) in patients with increased intracranial pressure. A wide range of regular ONSD values has been reported in the literature. The aim of this study was to determine normal values for OND and ONSD, to determine differences between OND and ONSD considering sex, age, and body mass index (BMI), and to evaluate inter - and intra - examiner variability. The study included 100 healthy subjects, aged 22 - 87 years, who underwent transbulbar sonography by the two examiners, each examiner measuring OND and ONSD twice on both eyes at a depth of 3 mm behind the optic nerve papilla. Measurement and analysis of OND and ONSD was possible in all subjects. Mean OND was 2.39 +/- 0.28 mm and mean ONSD was 4.48 +/- 0.76 mm. In males, mean OND was 2.47 +/- 0.28 mm and in females 2.35 +/- 0.27 mm (p = 0.042). There was no statistically significant difference between mean ONSD values between sexes (p &gt; 0.001). Correlation between age and mean OND and ONSD wasn`t observed. Positive correlation between mean OND and BMI (p = 0.001) was observed. Positive correlation within and between investigator measurements (p &lt; 0.01) was shown. Men have a wider OND compared to women, but no difference in ONSD was observed. Age doesn`t effect on the width of OND and ONSD. BMI correlates positively with OND, but not with ONSD. Positive correlation within and between investigator measurements was shown.

The value of the optic nerve sheath diameter measured using computerized brain tomography in the evaluation of mortality status in patients admitted to the emergency department with intracranial hemorrhage

Background/Aim: The optic nerve sheath diameter (ONSD) measurement is a non-invasive method that can be obtained from computerized tomography (CT) images. It can therefore be a useful diagnostic tool in determining prognosis in the emergency department. The aim of this study was to investigate the relationship between ONSD and mortality status in patients with intracranial hemorrhage who presented to the emergency department by measuring ONSD on computerized brain tomography images taken during admission. Methods: This retrospective cohort study was carried out in the emergency department of a tertiary hospital between December 1, 2018 and December 1, 2020 and included intracranial hemorrhage patients and patients with normal brain CT scans that had been obtained for any reason. Bilateral ONSDs were measured in both the intracranial hemorrhage and control groups. We first evaluated whether ONSD would differ between the two groups after which the relationship between ONSD and mortality was analyzed in the patient group who presented with bleeding. Results: Intracranial hemorrhage was present in half the cases and midline shift in 21.5%. A statistically significant increase in ONSD was observed in cases with intracranial hemorrhage (P &lt; 0.001). Similarly, a statistically significant increase in ONSD was found in cases with midline shifts and mortality (P &lt; 0.001). A cut-off value of 4.19 mm for mean optic nerve diameter exhibited 100% sensitivity and 70% specificity in terms of hemorrhage detection (area under the curve [AUC]: 0.952; P &lt; 0.001). A cut-off value of 6.03 mm for ONSD exhibited 76% sensitivity and 74% specificity in terms of hemorrhage detection (AUC: 0.730; P = 0.001). The odds ratio for prediction of mortality based on a regression analysis was 8.838 in cases with intracranial hemorrhage (P &lt; 0.001). Conclusion: ONSSD measured on CT images is a promising tool for prediction of intracranial hemorrhage, midline shift, and mortality status.

Trans-orbital sonographic assessment of optic nerve diameter in a sampled Nigerian population

Background: Studies have reported variants in the dimensions of optic nerve diameter among different ethnic groups, just as other body anatomy differs from regions to regions.Aim: To establish normal range of optic nerve diameter in a sampled Nigerian population, sonographically.Materials and Method: A total of 725 apparently healthy adult subjects (362 males aged 32 to 65 years and 363 females aged 30 to 68 years) were recruited from the South South and South Eastern parts of Nigeria for this prospective descriptive study. The optic nerve diameter (OND) was measured using a high-resolution digital dedicated small-parts real time ultrasound machine (Sonoace 5500; Medicol, Medison, Miami, FL, USA) with a high frequency (10-MHz) linear array transducer. Subjects were in supine position and were asked to keep their eyes closed and still. Coupling gel was placed on the closed eye lid with the transducer softly placed over the upper temporal eyelid in an axial plane. The OND was measured perpendicular to the vertical axis of the scanning plane as a horizontal distance between the two walls of the nerve sheath. The height and weight of the subjects were determined using a meter rule and a weighing scale.Results: The mean optic nerve sheath diameter of males and females was 4.2 ± 0.13 mm. It ranged from 4.0 to 4.45 mm. The optic nerve sheath diameter of males was not significantly different from that of females (p = 0.345). No significant difference between the mean OND of both eyes (p = 0.345). Body mass index and age did not have any association with OND (r = 0.017, 0.034), the data were normally distributed.Conclusion: Optic nerve diameter of apparently normal Nigerian adults ranges from 4.0 to 4.5 mm. Values outside this range may demand further evaluation in the study population.

Sonographic Optic Nerve Diameter and Clinical Biomarkers in Patients With Poorly Controlled Diabetes: A Comparative Analysis With Nondiabetic Subjects

Objective: The study assessed optic nerve diameter (OND) and clinical biomarkers in patients with poorly controlled diabetes compared with healthy nondiabetic volunteers. Materials and Methods: There were 1320 adult participants recruited to the study. The cohort was divided into 600 Type 2 diabetic (DM II) patients and 720 apparently healthy, nondiabetic volunteers. The OND was measured using a high-resolution dedicated ultrasound device (Sonoace 5500; Medicol, Medison, Miami, FL, USA) with a 10-MHz linear array transducer. Subjects were examined in a supine position with their eyes closed. Three measurements of the OND were taken and the average recorded. Hemoglobin A1c concentration and lipid profiles were determined using Bio-Rad Diamat analyzer (Bio-Rad, Hercules, CA). Body mass index and age were matched for both cohorts for comparativeness. Results: The mean OND of the DM II patients was 3.10 ± 0.14 mm (range of 2.6–4.0 mm), which was significantly ( P &lt; .05) lower than the control volunteers (4.22 ± 0.15 mm). The OND demonstrated a negative significant correlation with HA1c, duration of diabetes and low-density lipoprotein cholesterol level ( P &lt; .05). Lipid profiles, blood urea, serum creatinine, and hemoglobin A1c showed statistical difference between diabetics and control subjects. Conclusion: Poorly controlled DM II patients may have significantly narrower OND than nondiabetic patients. This imaging biomarker has the potential to transform visual care for DM II patients.

Optic Nerve Sheath Diameter Measured by Point-of-Care Ultrasound and MRI.

Ultrasound (US) measurement of the optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) is a method frequently used to screen for an increased intracranial pressure. The aim of this study was to assess the accuracy of US measurements of ONSD and OND, when compared to magnetic resonance imaging (MRI) measurements as the criterion standard. In this prospective, single-institution study, orbital US was performed for those patients requiring an emergent brain MRI. ONSD and OND of both eyes were measured in the axial and coronal planes in straight gaze by US. ONSD and OND from brain and orbital MRI were measured by two neuroradiologists. Correlation and agreement between readings were assessed using Pearson's correlations. Eighty-two patients met inclusion criteria. The mean axial and coronal ONSD in the MRI examinations was 5.6 and 5.7 mm at 3-5.9 mm behind the globe, respectively. The mean ONSD from the US measurements was 6.22 and 5.52 mm in the axial and coronal planes, respectively. The mean OND in US examinations was 4.31 mm (axial) and 3.68 mm (coronal). Axial versus coronal measurements of ONSD had a modest correlation in US assessment with an r2 of .385 (P < .001) but there were no correlations between any of the US and MRI measurements. In measuring ONSD and OND, US measurements showed a modest correlation between axial and coronal measurements, but no concordance was found between US and MRI in our setting.

The falciform ligament: Anatomical study with microsurgical implications

ObjectivesThe current study aims to increase awareness of the falciform ligament and its anatomical and surgical relationships, for the benefit of the neurosurgeon. Patinents and MethodsTwenty-four sides from twelve Caucasian cadaveric heads (all fresh-frozen) were used in this study. The length and thickness of the falciform ligament were recorded. The relationship of the falciform ligament to the optic nerve was also observed and documented. Finally, the force needed to avulse the falciform ligament was recorded. ResultsIn all specimens, the ligament was identified as a continuation of the outer dural layer, forming a roof at the entrance of the optic canal. The mean medial-to-lateral length, anteroposterior length, and thickness of the falciform ligament were 7.97 mm, 2.12 mm, and 0.26 mm, respectively. The mean distance from the medial attachment of the ligament to the midline was 5.54 mm. For the undersurface of the falciform ligament, the optic nerve occupied the middle third in 50.0 %, the lateral third in 44.4 %, and the medial third in 5.6 % of sides. The mean optic nerve diameter at the entrance of the optic canal was 4.20 mm. The mean failure force was 2.47 N. ConclusionThe anatomical measurements and relationships provided in this description of the falciform ligament serve as a tool for surgery selection and planning, as well as an aid to improving microsurgical techniques, with the final goal being better patient outcomes.

Pediatric optic nerve and optic nerve sheath diameter on magnetic resonance imaging.

The normal values of optic nerve diameter and optic nerve sheath diameter might be beneficial in defining an abnormality such as optic nerve hypoplasia, or enlarged subarachnoid space, reflecting the state of increased intracranial pressure. To study the normal optic nerve diameter and optic nerve sheath diameter on magnetic resonance imaging (MRI) in the early years of postnatal visual development from MRI of the brain. MRI of the brain in patients ages 4years and younger were gathered. Forty-two studies with normal intracranial findings and a lack of history of increased intracranial pressure were retrospectively reviewed by two reviewers using axial T2-weighted images. Measurements were performed in transverse diameter perpendicular to the optic nerve at 3mm behind the globe. The mean optic nerve diameter of the 77 optic nerves were 2.5 mm (95% confidence interval [CI] 2.4-2.6). The mean optic nerve sheath diameter values of the 79 optic nerve sheath complexes were 5.0 mm (95% CI 4.9-5.1). The mean±standard deviation optic nerve diameter and optic nerve sheath diameter stratified by each age groups were, respectively, 0 to <1year: 2.3±0.40 and 4.81±0.37; 1 to <2years: 2.6±0.2 and 5.0±0.4; 2 to <3years: 2.4±0.3 and 4.9±0.6, and 3 to <4years: 2.9±0.4 and 5.2±0.60mm. Seventy-four of the 77 measurements (96%) were of the measurements were above the threshold of 2mm for optic nerve diameter. Seventy-seven of the 79 measurements (97%) were of the measurements were below the threshold of 6mm for optic nerve sheath diameter.

Color Doppler imaging evaluation of blood flow parameters in ophthalmic and posterior ciliary arteries and optic nerve diameter in chronic optic neuritis in multiple sclerosis patients

Background and purposeOptic neuritis (ON) is a common clinical manifestation of Multiple Sclerosis (MS), which is associated with reduced visual acuity, blurred vision, blindness and retro-bulbar pain. In several studies, specific relations between optic nerve diameter and hemodynamics of the eye bulb arteries with ON have been reported. However, no consensus has been reached in this regard. We aim at determining the alterations in optic nerve diameter and eye bulb arteries hemodynamics in ON in MS patients. MethodsThis case-control study includes 40 patients, who at least had experienced one phase of ON, in one of their eyes. To measure hemodynamics of arteries in the affected eyes, a color Doppler imaging was performed and end diastolic velocity (EDV), peak systolic velocity (PSV), peripheral resistance indices i.e. resistance index (RI) and pulsatile index (PI) were measured in posterior ciliary artery (PCA) and ophthalmic artery (OA). Also, optic nerve diameter was measured using sonography. Non-affected eyes of these patients were considered as control group. ResultsThere were no significant differences in EDV, PSV, RI and PI in PCA and OA. The mean optic nerve diameter in the affected eyes was 4.73 mm, whereas, it was 4.31 mm in unaffected eyes, which was significantly different (P = .02). ConclusionThese results indicate that there is a significant relation between eye involvement and increased optic nerve diameter in MS patients with chronic ON. While, there were no significant relations in EDV, PSV, RI and PI in PCA and OA comparing two groups.

Transorbital Sonography and Visual Outcome for the Diagnosis and Monitoring of Optic Neuritis.

Transorbital sonography (TOS) is a promising tool to support the clinical diagnosis of optic neuritis (ON) by showing thickening of optic nerve. In this study, we aimed to define its specific role in follow-up of ON patients. We measured ultrasonography parameters and visual acuity (VA) at presentation and after 1 year in 45 patients with newly diagnosed ON. Two vascular sonographers used B-mode TOS to evaluate mean optic nerve diameter (OND) and optic nerve sheath diameter (ONSD). Median ONSD values were significantly thicker in patients with ON in the affected eye (6.4 mm, interquartile range [IQR]: 6.0-6.9) at presentation compared with the nonaffected side (5.7 mm; IQR: 5.2-6.1) (P < .001). The median OND was not significantly thicker at presentation in the affected eye (3.0 mm; IQR: 2.9-3.4) compared with the fellow eye (2.9 mm; IQR: 2.8-3.2) (P = .09). Logarithmic VA was significantly compromised at presentation in the affected eye (.16; IQR: .00-.55) compared with fellow eye (.00; IQR: .00-.00) (P < .001). After 1 year, no significant difference (P ≥ .05) was found between ONSD or OND of the affected side compared with the nonaffected side. VA improved in most of the patients but remained significantly impaired in affected eye after 1 year. TOS is a useful tool to support diagnosis of ON. This technique seems to have less value to evaluate atrophy of the optic nerve after 12 months.

Ultrasonic Elastography Evaluation in Optic Neuritis

ABSTRACTPurpose: In the present study, we attempted to determine whether ultrasonic elastography (USE) evaluation can be used in a diagnosis of optic neuritis (ON). Materials and Methods: Thirteen patients who each had one normal eye and one eye with a diagnosis of ON were included in the study. Ultrasonography (US) and USE examinations were performed on the affected and non-affected eyes of all participants. Optic nerve and adjacent fat tissue regions at the same depth were selected, and USE measurements were obtained. The optic nerve diameter was measured in both normal and affected eyes. Results: The mean USE values for the optic nerve were 2.58 ± 0.50 m/s in ON eyes and 1.91 ± 0.39 m/s in normal eyes (p = 0.001). The mean USE values for the optic-nerve adjacent tissue were 2.26 ± 0.45 m/s in ON eyes and 1.77 ± 0.22 m/s in normal eyes (p = 0.001). The mean optic-nerve diameter was 3.80 ± 1.09 mm in ON eyes and 3.28 ± 0.98 mm in normal eyes (p = 0.005). Conclusions: USE may be considered an accessible, safe technique for the detection of significant optic-nerve tissue stiffness in ON and may be used an adjunctive tool for confirming this diagnosis.

The Role of Magnetic Resonance Imaging in Diagnosing Optic Nerve Hypoplasia

To establish objective lower limits of normal optic nerve (ON) size in children based on high-resolution orbital magnetic resonance imaging (MRI). Case-control study of patients with ON hypoplasia vs normal controls. A neuroradiologist made 4 measurements of each ON at 2 locations (5 mm posterior to the optic disc and just posterior to the optic canal) in patients with ON hypoplasia and controls aged 0-17 years from an academic eye center and children's hospital. Primary analyses were performed using mixed linear models. Measurements were made in 26 cases of clinically confirmed ON hypoplasia and 31 controls (median age: ON hypoplasia, 1 year; controls, 5.5 years). Nine of 26 cases (35%) and 19 of 31 controls (61%) underwent high-resolution T2-weighted imaging of the orbits. Mean ON diameter was 1.36 mm (95% CI: 1.19-1.54; P < .001) smaller for clinically hypoplastic ONs than for controls. Optic nerve diameter increased by 0.05 mm per year of age (95% CI: 0.03-0.07; P < .001). A lower bound to the 95% prediction interval for normal optic nerves was (2.24 mm + 0.052 × [age in years]) mm and excluded all but 1 case. Age was independently associated with normal ON size by MRI and should be taken into consideration when evaluating ON hypoplasia, based on MRI criteria. We have provided a formula to assist clinicians in objectively determining if ON hypoplasia is present.

The role of magnetic resonance imaging in diagnosing optic nerve hypoplasia

Purpose To establish objective lower limits of normal optic nerve (ON) size in children based on high-resolution orbital magnetic resonance imaging (MRI). Design Case-control study of patients with ON hypoplasia vs normal controls. Methods A neuroradiologist made 4 measurements of each ON at 2 locations (5 mm posterior to the optic disc and just posterior to the optic canal) in patients with ON hypoplasia and controls aged 0–17 years from an academic eye center and children's hospital. Primary analyses were performed using mixed linear models. Results Measurements were made in 26 cases of clinically confirmed ON hypoplasia and 31 controls (median age: ON hypoplasia, 1 year; controls, 5.5 years). Nine of 26 cases (35%) and 19 of 31 controls (61%) underwent high-resolution T2-weighted imaging of the orbits. Mean ON diameter was 1.36 mm (95% CI: 1.19–1.54; P P Conclusions Age was independently associated with normal ON size by MRI and should be taken into consideration when evaluating ON hypoplasia, based on MRI criteria. We have provided a formula to assist clinicians in objectively determining if ON hypoplasia is present.

(P2-73) Ocular Nerve Sheath Diameter for Evaluation of Raised Intracranial Pressure in Patients Presenting to the Emergency Department - A Prospective, Observational Study

BackgroundUltrasonography of optic nerve sheath diameter (ONSD) may be useful in detecting raised intracranial pressure (ICP) in head injury (HI). There is limited data from India.ObjectiveThe objective of this study was to evaluate the utility of measuring ONSD for diagnosis of raised intracranial pressure in HI victims in the emergency department.MethodsFifty-two HI patients presenting between February to August 2009 were included, A CT head scan was performed and simultaneous ocular ultrasound was done by an emergency physician who had underwent goal-directed training in ophthalmic sonography by a linear probe of 10 MHz. An ONSD greater than &gt; 5 mm for patients &gt; 15 years of age, 4.5 mm for 1–15 years of age, and 4 mm for infants were considered abnormal. The two modalities of diagnosis were compared.ResultsThe median age was 30 years (Range = 0.25–72 years). A total of 90.4% were male and 9.6% were female. A total of 71.2% had severe HI, 19.2% had moderate HI, and 9.6% had mild HI. A raised ICP based on CT findings was present in 42 (80.8%) patients. Mean optic nerve diameter in patients with raised ICP was 5.11 + 1.56 mm compared to 5.04 + 1.6 mm in patients with no features of raised ICP. Sensitivity and specificity of ONSD as a screening test for detection of raised intracranial pressure were 57.1% and 40%, respectively with a positive predictive value and negative predictive value of 80% and 18.1%, respectively.ConclusionsThe evaluation of the ONSD diameter is a simple and non-invasive potential tool in initial assessment of raised intracranial pressure.

Optic Nerve Sheath Fenestration for Treatment of Progressive Ischemic Optic Neuropathy-Reply

In reply McHenry and Spoor raise an interesting point that fluid accumulation in theperioptic meninges may be associated with a progressive course of visual loss and better surgical outcome following ONSD in patients with AION. In our series of 26 eyes with progressive AION,1only one of 17 eyes showed meager increased fluid in the subarachnoid space. In fact, in the Echography Laboratory of the Bascom Palmer Eye Institute, Miami, Fla, using standardized A-scan echography, we do not find increased sheath fluid in cases of AION, whether progressive or static. The surgical series of Spoor et al2was recently published, including sonographic data on 12 eyes with progressive AION and 27 eyes with static AION. Mean optic nerve diameter in the progressive group was 3.47 mm, with afluid shift (30° test) rangingfrom 5% to 25%, and mean optic nerve diameter in the static group was 3.19 mm, with afluid shift