Optic Nerve Evaluation in Idiopathic Intracranial Hypertension

Impact of Brightness on Choroidal Vascularity Index

The use of choroidal vascularization to diagnose and follow-up ocular and systemic pathologies has been consolidated in recent research. Unfortunately, the choroidal parameters can be different depending on the lighting settings of optical coherence tomography (OCT) images. The purpose of this study was to examine whether the brightness of OCT images could influence the measurements of choroidal parameters obtained by processing and analyzing scientific images with the ImageJ program. In this observational, prospective, non-randomized study, 148 eyes of 74 patients with a mean age of 30.7 ± 8.5 years (ranging from 23 to 61 years) were assessed. All patients underwent a complete ophthalmological examination including slit lamp, fundus oculi, ocular biometry, corneal tomography and spectral domain (SD) OCT evaluations of the foveal region in the enhanced depth imaging (EDI) mode. OCT images at two different brightness levels were obtained. The total choroidal area (TCA), choroidal vascularity index (CVI), stromal choroidal area (SCA) and luminal choroidal area (LCA) at both lower and higher brightness levels were measured. To avoid the bias of operator-dependent error, the lower and higher brightness TCAs were obtained using two methods: the manual tracking mode and fixed area. At the two different brightness levels, LCA, SCA and CVI measurements showed statistically significant changes (p < 0.05), whereas the TCA differences were not statistically significant (p > 0.05). According to the results of this study, highlighting that brightness could affect LCA, SCA and CVI parameters, care should be taken during OCT image acquisition.

Optic Nerve Changes Detected with Ocular Ultrasonography during Different Surgical Procedures: A Narrative Review

Ultrasonographic appraisal of the optic nerve sheath diameter has become popular in recent years as a useful diagnostic tool to detect intracranial pressure variations. Intracranial hypertension is a life-threatening disease with possible poor clinical outcomes and can be caused by a variety of neurological and non-neurological conditions. Considering the latter, increases in intracranial pressure have also been described during several surgical procedures. Ocular ultrasonography might be utilized to identify intracranial pressure increases by evaluating optic nerve sheath diameter variations. The aim of this review is to provide a wide overview on the use of the optic nerve ultrasound evaluation to detect intracranial pressure changes during surgical procedures, also discussing the pitfalls of the B-scan technique, the most widely used for such a purpose. PubMed medical database, Web of Science and Scopus were used to carry out this review. The present review showed that ocular ultrasonography could be considered a valuable diagnostic tool in the surgical setting to indirectly assess intracranial pressure. However, the use of the B-scan ultrasound should always be coupled with the standardized A-scan technique for a more accurate, precise and trustworthy ultrasound assessment.

Ultrasound Detection of Intracranial Hypertension in Brain Injuries

In recent years, the measurement of optic nerve sheath diameter with ultrasound to detect the presence of increased intracranial pressure has widely spread. It can be qualitatively and effectively used to identify intracranial hypertension. Intracranial pressure can rise due to acute injury, cerebral bleeding, hydrocephalus, brain tumors and other space-occupying abnormalities, and it is linked to a high death rate. The purpose of this review is to give a general overview of the most relevant scientific publications on ultrasonographic evaluation of the optic nerve in case of brain injuries published in the last 30 years, as well as to analyze the limits of the most extensively used B-scan approach. Fifty-two papers chosen from the PubMed medical database were analyzed in this review. Our findings revealed that ocular ultrasound is an useful diagnostic tool in the management of intracranial hypertension when it exceeds a certain value or after head trauma. As a result, an ultrasound of the optic nerve can be extremely helpful in guiding diagnosis and treatment. The blooming effect is one of the most critical restrictions to consider when using B-scan ultrasonography. Since amplitude-scan ultrasound, also known as A-scan, does not have this limit, these two diagnostic techniques should always be used together for a more full, accurate, and trustworthy ultrasound examination, ensuring more data objectivity.

Optic Nerve Drusen Evaluation: A Comparison between Ultrasound and OCT

This observational study compared optic coherence tomography (OCT) and B-scan in the detection of optic disc drusen. In total, 86 eyes of 50 patients with optic disc drusen (ODD) (36 bilateral) with a mean age of 34.68 ± 23.81 years, and 54 eyes of 27 patients with papilledema, with a mean age of 35.42 years ± 17.47, were examined. Patients with ODD, diagnosed with ultrasound, underwent spectral-domain OCT evaluation. With US, 28 ODD cases were classified as large (4 buried and 24 superficial), 58 were classified as point-like (6 buried, 49 superficial and 3 mixed). Then, all patients underwent OCT. OCT was able to detect the presence of ODD and/or peripapillary hyperreflective ovoid mass structure (PHOMS) in 69 eyes (p < 0.001). In particular, 7 eyes (8.14%) showed the presence of ODD alone, 25 eyes (29.07%) showed only PHOMS and 37 eyes (43.02%) showed ODD and PHOMS. In 17 eyes (19.77%) no ODD or PHOMS were detected. In the papilledema group, no ODD were observed with both US and OCT. OCT showed the presence of drusen or similar lesions in only 80.23% of the cases highlighted by the US scan, so it does not allow for certain ODD diagnoses, especially in the case of buried ODD.

Effect of Percutaneous Tracheostomy on Optic Nerve Sheath Diameter (TONS Trial)

How to cite this article: Di Paola I, Graziano M, Cornetta P. Effect of Percutaneous Tracheostomy on Optic Nerve Sheath Diameter (TONS Trial). Indian J Crit Care Med 2022;26(5):653.

Optic Nerve Ultrasound Evaluation in Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is a disease with a heterogeneity of possible causes, which needs to be quickly diagnosed. Ocular ultrasonography could be considered a useful tool to diagnose this condition in a fast and non-invasive way. In fact, Karl Ossoinig had already proposed this diagnostic tool in the 1970s for the evaluation of intracranial pressure changes under several pathological conditions, including idiopathic intracranial hypertension. The aim of this review is to analyze scientific articles published in the last 30 years concerning the use of ocular ultrasonography to assess optic nerve indices in patients with idiopathic intracranial hypertension. Specifically, 15 published articles found in PubMed database were included and analyzed in the present review. Our conclusion suggests that ocular ultrasonography is a reliable diagnostic technique to be utilized in all the cases of suspected raised intracranial pressure. To obtain the best possible accuracy and precision in the least invasive way, standardized A-scan seems to be the best choice.

Optic Nerve Ultrasound Evaluation in Animals and Normal Subjects

In recent years, ultrasonographic measurement of the optic nerve sheath diameter (ONSD) has been widely used to identify the presence of increased intracranial pressure (ICP). Intracranial hypertension is a life-threatening condition that can be caused by various neurological and non-neurological disorders, and it is associated to poor clinical results. Ultrasonography could be used to qualitatively and efficiently detect ICP increases, but to reach this purpose, clear cut-off values are mandatory. The aim of this review is to provide a wide overview of the most important scientific publications on optic nerve ultrasound normal values assessment published in the last 30 years. A total of 42 articles selected from PubMed medical database was included in this review. Our analysis showed that ocular ultrasonography is considered to be a valuable diagnostic tool, especially when intracranial hypertension is suspected, but unfortunately this research provided conflicting results that could be due to the different ultrasound protocols. This is mainly caused by the use of B scan alone, which presents several limitations. The use of B-scan coupled with the standardized A-scan approach could give more accurate, and reliable ultrasound evaluation, assuring higher data objectivity.

Sensitivity and specificity of neuroimaging signs in patients with idiopathic intracranial hypertension

BACKGROUND

The primary role of neuroimaging in idiopathic intracranial hypertension (IIH) is to exclude secondary causes of raised intracranial pressure. Recently, a few imaging markers have been described which may suggest diagnosis of IIH in atypical cases. We carried out this study to assess the prevalence and accuracy of these neuroimaging signs in predicting the diagnosis of IIH.

METHODS

Eighty treatment-naive patients with IIH and 30 controls were recruited as per a predefined criterion. Magnetic resonance imaging (MRI) brain with detailed sella imaging was done in all patients.

RESULTS

The most common abnormality noted was optic nerve tortuosity in 82.5% of patients, followed by posterior scleral flattening in 80%, perioptic subarachnoid space (SAS) dilatation in 73.8% and partial empty sella in 68.8% of patients. The presence of optic nerve tortuosity was the most sensitive sign on neuroimaging, though the highest specificity was seen for posterior scleral flattening and perioptic SAS dilatation. The presence of more than three neuroimaging features correlated with severity of vision loss.

CONCLUSION

In suggestive clinical scenarios, posterior scleral flattening, perioptic SAS dilatation and optic nerve tortuosity are highly sensitive and specific signs in IIH. This study also highlights the utility of MRI as a valuable tool for prognosis of visual outcome in patients with IIH.

Pediatric liver diseases and ocular changes: What hepatologists and ophthalmologists should know and share with each other

Several rare pediatric liver disorders are accompanied by ophthalmic signs whose awareness and early identification may be of value in confirming/accelerating their diagnosis. Many of these signs are asymptomatic and can only be detected with an ophthalmological examination. Corneal signs are described in patients with Wilson's disease, Alagille's syndrome and some liver storage diseases. Cataract plays an important role to diagnose galactosemia. Retinal involvement is seen in some peroxisomal disorders (e.g. Zellweger's syndrome), in mucopolysaccharidoses (pigmentary retinopathy), and in Niemann-Pick disease (macular cherry red spot). In mucopolysaccharidoses optic nerve can be involved as optic atrophy secondary to pigmentary retinopathy or to chronic papilledema. Children with neonatal cholestasis due to hypopituitarism may present septo-optic dysplasia. Several infectious agents have an ophthalmological/hepatic involvement in the fetal life and/or thereafter. Some mitochondrial liver diseases, such as Pearson's syndrome, present pigmentary retinopathy and a chronic progressive external ophthalmoplegia. Finally, some drugs while protecting the liver may damage the ocular system as seen with long-term glucocorticoids and Nitisinone administration. This review provides a synopsis of those conditions that hepatologists and ophthalmologists should share among themselves to better take care of patients. Synoptic tables are presented to facilitate the mutual understanding of the issues.