Prospective Clinical Study of Non-Invasive Intracranial Pressure Measurements in Open-Angle Glaucoma Patients and Healthy Subjects

Is Glaucoma a Two-Pressure-Related Optic Neuropathy? A Systematic Review and Meta-Analysis

Objectives

To review the current literature related to the correlation between translaminar pressure difference (TLPD) and glaucoma.

Materials and Methods

In this article, we conducted a literature review using MEDLINE via PubMed, Cochrane Eyes and Vision, and Google Scholar from 01/01/2010 to 31/12/2022. Search terms included "glaucoma", "intraocular pressure", "translaminar cribrosa pressure gradient/difference", "intracranial pressure", and "cerebrospinal fluid pressure". Of 471 results, 8 articles were selected for the meta-analysis.

Results

Our meta-analysis demonstrated significantly higher intraocular pressure, lower cerebrospinal fluid pressure (CSFp), and greater TLPD in high-tension and normal-tension glaucoma groups compared to healthy groups.

Conclusion

The differences in CSFp and TLPD between glaucoma and healthy people detected in current studies suggests a potential relationship between TLPD and glaucoma.

Investigating the Structural and Functional Changes in the Optic Nerve in Patients with Early Glaucoma Using the Optical Coherence Tomography (OCT) and RETeval System

The present manuscript introduces an investigation of the structural and functional changes in the optic nerve in patients undergoing glaucoma treatment by comparing optical coherence tomography (OCT) measurements and RETeval system parameters. For such a purpose, 140 eyes were examined at the Ophthalmology Clinic of the "Elpis" General Hospital of Athens between October 2022 and April 2023. A total of 59 out of 140 eyes were from patients with early glaucoma under treatment (case group), 63 were healthy eyes (control group) and 18 were excluded. The experimental measurements were statistically analyzed using the SPSS software package. The main outcomes are summarized below: (i) there was no statistical difference between the right and left eye for both groups, (ii) statistical differences were found between age interval subgroups (30-54 and 55-80 years old) for the control group, mainly for the time response part of the RETeval parameters. Such difference was not indicated by the OCT system, and (iii) a statistical difference occurred between the control and case group for both OCT (through the retinal nerve fiber layer-RNFL thickness) and the RETeval parameters (through the photopic negative response-PhNR). RNFL was found to be correlated to b-wave (ms) and W-ratio parameters. In conclusion, the PhNR obtained by the RETeval system could be a valuable supplementary tool for the objective examination of patients with early glaucoma.

Cerebrospinal fluid and ophthalmic disease

PURPOSE OF REVIEW

The purpose of this review is to discuss the contemporary body of literature examining the relationship between cerebrospinal fluid (CSF) and ophthalmic disease. This review focuses on diseases that have a pathogenesis related to the translaminar pressure difference, defined as the pressure difference between the orbital subarachnoid space (OSAS) and the intraocular pressure. The diseases discussed include glaucoma, idiopathic intracranial hypertension, and spaceflight associated neuro-ocular syndrome.

RECENT FINDINGS

The relationship between cerebrospinal and ophthalmic disease has been investigated for over 100 years. Recent research provides insight into the mechanisms that dictate CSF circulation in the OSAS and how alterations in these mechanism lead to disease. This review discusses these recent findings and their relationship to major ophthalmic diseases.

SUMMARY

The recent findings provide insight into diseases that have pathogenic mechanisms that are not fully understood. This information will help physicians gain a clearer understanding of the relationship between CSF and ophthalmic disease and guide future research.

Human ophthalmic artery as a sensor for non-invasive intracranial pressure monitoring: numerical modeling and in vivo pilot study

Intracranial pressure (ICP) monitoring is important in managing neurosurgical, neurological, and ophthalmological patients with open-angle glaucoma. Non-invasive two-depth transcranial Doppler (TCD) technique is used in a novel method for ICP snapshot measurement that has been previously investigated prospectively, and the results showed clinically acceptable accuracy and precision. The aim of this study was to investigate possibility of using the ophthalmic artery (OA) as a pressure sensor for continuous ICP monitoring. First, numerical modeling was done to investigate the possibility, and then a pilot clinical study was conducted to compare two-depth TCD-based non-invasive ICP monitoring data with readings from an invasive Codman ICP microsensor from patients with severe traumatic brain injury. The numerical modeling showed that the systematic error of non-invasive ICP monitoring was < 1.0 mmHg after eliminating the intraorbital and blood pressure gradient. In a clinical study, a total of 1928 paired data points were collected, and the extreme data points of measured differences between invasive and non-invasive ICP were - 3.94 and 4.68 mmHg (95% CI - 2.55 to 2.72). The total mean and SD were 0.086 ± 1.34 mmHg, and the correlation coefficient was 0.94. The results show that the OA can be used as a linear natural pressure sensor and that it could potentially be possible to monitor the ICP for up to 1 h without recalibration.