Inessa Bekerman

Variations in Eyeball Diameters of the Healthy Adults

The purpose of the current research was to reevaluate the normative data on the eyeball diameters. Methods. In a prospective cohort study, the CT data of consecutive 250 adults with healthy eyes were collected and analyzed, and sagittal, transverse, and axial diameters of both eyeballs were measured. The data obtained from the left eye and from the right eye were compared. The correlation analysis was performed with the following variables: orbit size, gender, age, and ethnic background. Results. We did not find statistically significant differences correlated with gender of the patients and their age. The right eyeball was slightly smaller than the left one but this difference was statistically insignificant (P = 0.17). We did not find statistically significant differences of the eyeball sizes among the ethnicities we dealt with. Strong correlation was found between the transverse diameter and the width of the orbit (r = 0.88). Conclusion. The size of a human adult eye is approximately 24.2 mm (transverse) × 23.7 mm (sagittal) × 22.0–24.8 mm (axial) with no significant difference between sexes and age groups. In the transverse diameter, the eyeball size may vary from 21 mm to 27 mm. These data might be useful in ophthalmological, oculoplastic, and neurological practice.

Diagnostic value of the optic nerve sheath diameter in pseudotumor cerebri

If persistent severe headache remains the only complaint of a patient, then the diagnosis of pseudotumor cerebri (PTC) can be delayed because in such cases practitioners are hesitant to immediately apply invasive intracranial pressure (ICP) measurement. Our purpose was to apply the technique of measuring diameters of the optic nerve sheath (ONSD) as a diagnostic tool in cases of PTC. Our aim was to provide practitioners with an additional sign to speed up their decision making about implementation of the lumbar puncture. In a retrospective study, CT scan data of 35 consecutive adult patients with PTC were collected and analyzed. ONSD were measured at the point where the ophthalmic artery crosses the optic nerve (anatomical landmark). The correlation analysis was performed with sex, age, and neuro-ophthalmological findings. We found that the ONSD was enlarged in 94.3% of patients with PTC. The enlarged ONSD were 6.2±1.2mm for the right and 6.3±0.9mm for the left (cut-off value >5.5mm). The enlargement was bilateral, and no correlation with age or sex was found (p=0.67 and p=0.76, respectively). Presence of papilledema was detected in 91.4% of patients (32/35) presenting as a slightly less valuable diagnostic sign compared with ONSD. We conclude that in the majority of cases of PTC the ONSD is significantly enlarged, indicating elevated ICP even if CT scans are negative. Implementing this ONSD method as a diagnostic tool in cases of suspected PTC may help in early accurate diagnosis, avoiding misdiagnosis, and providing appropriate early treatment.

Monitoring of Intracranial Pressure by CT-Defined Optic Nerve Sheath Diameter.

Intracranial pressure (ICP) can be monitored by the optic nerve sheath diameter (ONSD) technique. We hypothesized that diameter of the optic canal (OC) can be a limiting factor for this technique.

The quantitative evaluation of intracranial pressure by optic nerve sheath diameter/eye diameter CT measurement

BACKGROUND The changes of the optic nerve sheath diameter (ONSD) have been used to assess changes of the intracranial pressure for 20 years. The aim of this research was to further quantify the technique of measuring the ONSD for this purpose. METHODS Retrospective study of computed tomographic (CT) data of 1766 adult patients with intracranial hypotension (n=134) or hypertension (n=1632) were analyzed. The eyeball transverse diameter (ETD) and ONSD were obtained bilaterally, and the ONSD/ETD ratio was calculated. The ratio was used to calculate the normal ONSD for patients and to estimate the intracranial pressure of the patients before and after the onset of the pathology. Correlation analysis was performed with invasively measured intracranial pressure, the presence or absence of papilledema, sex, and age. RESULTS In hypotension cases, the ONSD by CT was 3.4±0.7 mm (P=.03 against normative 4.4±0.8 mm). In cases with hypertension, the diameter was 6.9±1.3 (P=.02, with a cutoff value ˃5.5 mm). The ONSD/ETD ratio was 0.29±0.04 against 0.19±0.02 in healthy adults (P=.01). CONCLUSION The ONSD and the ONSD/ETD ratio can indicate low intracranial pressure, but quantification is impossible at intracranial pressure less than 13 mm Hg. In elevated intracranial pressure, the ONSD and the ratio provide readings that correspond to readings in millimeters of mercury. The ONSD method, reinforced with additional calculations, may help to indicate a raised intracranial pressure, evaluate its severity quantitatively, and establish quantitative goals for treatment of intracranial hypertension, but the limitations of the method are to be taken into account.

Noninvasive assessment of the intracranial pressure in non-traumatic intracranial hemorrhage

The article describes the modified technique of measuring the diameters of the optic nerve sheath (ONSD) for assessment of the intracranial pressure (ICP) in patients with intracerebral or subarachnoid hemorrhage (SAH). The CT scans of 443 patients were analyzed retrospectively. The ONSDs were measured at 3mm behind the globe and at the point where the ophthalmic artery crosses the optic nerve. The ONSD/eyeball transverse diameter (ETD) ratio was calculated. The correlation analysis was performed with the Glasgow Coma Scale score, Hemispheric Stroke Scale score, Glasgow Outcome Score, and invasive ICP readings. ONSD was enlarged in 95% of patients with intracerebral hemorrhage or SAH. Pathological ONSDs were 6.6±0.8mm (cut-off value >5.5mm; p<0.05). ONSD/ETD ratio was 0.29±0.05 against normative 0.19±0.02 (p<0.01) with no correlation with initial Glasgow Coma Scale score or Hemispheric Stroke Scale score. There was an inverse correlation between ONSD/ETD ratio and Glasgow Outcome Score (r=-0.7) and direct correlation with invasive ICP readings. This study provides further evidence that in patients with intracranial hemorrhage and SAH, the presence of ONSD greater than a threshold of 5.5mm is significantly predictive of invasively measured elevated ICP. The prediction of raised ICP can be further refined by measuring ONSD at the point where the optic nerve and the ophthalmic artery cross, and by determining the ratio between the ONSD and ETD.

Optic nerve sheath diameters in healthy adults measured by computer tomography.

AIM To measure optic nerve sheath diameters (ONSD) in different locations by computer tomography (CT) and to recommend the best location for cases when ONSD is used for intracranial pressure monitoring. METHODS In a prospective cohort study, CT data of 300 healthy adults were analyzed (600 eyes). In all cases, the CT investigation was performed at the Emergency Department because of the various conditions that proved not to be connected with ophthalmological or neurological pathology. The ONSD were measured at 3 mm and 8 mm distance from the globe, and 3 mm from the anterior opening of the optic canal. The correlation analysis was performed with gender, age, and ethnic background. RESULTS The right/left ONSD are 4.94±1.51/5.17±1.34 mm at 3 mm, 4.35±0.76/4.45±0.62 mm at 8 mm from the globe, and 3.55±0.82/3.65±0.7 mm at 3 mm from the optic canal. No significant differences correlated with gender of the patients, their age, and ethnic background were found. CONCLUSION In healthy persons, the ONSD varies from 5.17±1.34 mm to 3.55±0.82 mm in different locations within the intraorbital space. The most stable results with lesser standard deviation can be obtained if it is measured 8-10 mm from the globe.

Initial evaluation of the intracranial pressure in cases of traumatic brain injury without hemorrhage

Our objective was to apply the technique of measuring diameters of optic nerve sheath (ONSD) for the intracranial pressure assessment for the cases with traumatic head injury without hemorrhage. In a retrospective study, CT data of 720 adult patients were collected and analyzed. ONSDs were measured at the point where the ophthalmic artery crosses the optic nerve (anatomical landmark) together with the eyeball transverse diameter (ETD). The ONSD/ETD index was calculated. The correlation analysis was performed with gender, age, the Glasgow Coma Scale score, and the Glasgow Outcome Score. ONSD was enlarged in 82% cases (n=591). Enlarged right/left ONSDs were 6.7±1.0/6.7±0.9mm (cut-off value˃5.5mm). ONSD/ETD ratio was 0.28±0.05 against 0.19±0.02 in healthy adults (p=0.02). We did not find correlation between ONSD/ETD ratio with initial Glasgow Coma Scale score but there was an inverse correlation between ONSD/ETD ratio and the Glasgow Outcome Score (r=-0.64). We conclude that in majority of cases with traumatic head injury without hemorrhage the ONSD is significantly enlarged indicating elevated intracranial pressure even if CT scans are negative.

MRI measurements of the normal pediatric optic nerve pathway

The purpose of this work is to establish a reference scale of optic nerve pathway measurements in pediatric patients according to age using MRI. Optic nerve pathway measurements were retrospectively analyzed using an orbits equivalent sequence on brain MRI scans of 137 pediatric patients (72 male, 65 female, average age = 7.7 years, standard deviation  = 5.3). The examinations were performed on a 1.5-T or 3-T Siemens MR system using routine imaging protocols. Measurements include diameters of the orbital optic nerves (OON), prechiasmatic optic nerves (PON), optic tracts (OT), and optic chiasm (OC). Measurements were performed manually by 2 neuroradiologists, using post-processing software. Patients were stratified into five age groups for measurement analyses: (I) 0-1.49 years, (II) 1.5-2.99 years, (III) 3-5.99 years, (IV) 6-11.99 years, and (V) 12-18 years. The observed value range of OON mean diameter was 2.7 mm (Interquartile range (IQR) = 2.4-2.9), PON was 3.2 mm (IQR  =  3.05-3.5), OT 2.6 mm (IQR = 2-2.9). A strong positive correlation was established between age and mean diameter of OON (r = 0.73, p < .001), PON (r = 0.59, p < .001), and OT (r = 0.72, p < .001). A significant difference in mean OON diameters was found between age groups I-II (d = 0.3, p = .01), II-III (d = 0.5, p < .001), III-IV (d = 0.5, p < .001) followed by a plateau between IV-V (d = 0.l0, p = .19). OON/OT ratio maintained a steady mean value 1 (IQR = 0.93-1.1) regardless of age (p = .7). The diameter of optic pathways was found to increase as a function of age with consistent positive correlation between nerve and tract for all ages.

Surgical approach to the intrathoracic goiter: Surgical Approach to Intrathoracic

In a retrospective study, the authors analyzed the surgical approach to the intrathoracic goiter to avoid sternotomy or thoracotomy.