Pressure Difference Between Brain and Eye: a Possible Cause to Normal Tension Glaucoma.
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|ClinicalTrials.gov Identifier: NCT02776449|
Recruitment Status : Completed
First Posted : May 18, 2016
Last Update Posted : May 3, 2017
|Condition or disease|
|Normal Tension Glaucoma|
The trans-lamina cribrosa pressure difference (TLCPD), i.e. the difference between the intraocular pressure (IOP) and the intracranial pressure (ICP) has been suggested as a pathophysiological component in glaucoma. The theory is that high TLCPD, either due to elevated IOP or reduced ICP, can cause glaucomatous damage.
Normal tension glaucoma (NTG) patients has been found to have a slightly reduced ICP when measured in horizontal position. However, in a previous study in healthy adult volunteers the investigators have measured TLCPD at supine, sitting and 9 degree head down tilt positions and found that the TLCPD was posture dependent, with the largest difference in the upright position. Since humans are upright approximately two thirds of the day, one can expect that TLCPD in a diurnal perspective is primarily influenced by the ICP in the upright position.
In this study the TLCPD in different positions in patients with NTG will therefore be measured.
The study will be carried out in three parts.
- TLCPD will be investigated by simultaneous measurements of IOP and ICP. For IOP the Applanation resonance tonometer (ART), developed by our research group, will be used. ART is independent of gravitation and possible to use in all body postures. In this study measurements will be performed in supine, sitting and head down tilt positions. ICP is measured continuously during the period of body position changes with a CELDA lumbar pressure measurement apparatus.
- Brain and eye MRI investigation will be performed at a 3 Tesla GE scanner with a new generation 32-channels head coil. The images will be used to measure the cross-section area, the blood flow velocity and the flow direction in the jugular veins, as well as the structural properties of the optic nerve and optic nerve head.
- Ultrasound imaging, using a high-resolution apparatus, will be performed to study the effects of postural changes on the blood flow velocity and the cross-section area of the right and left internal jugular veins and external jugular veins.
|Study Type :||Observational|
|Actual Enrollment :||17 participants|
|Official Title:||Pathological Cerebral Venous Drainage System Giving Large Pressure Difference Between Brain and Eye at Upright Posture: a Possible Cause to Normal Tension Glaucoma.|
|Study Start Date :||February 2016|
|Actual Primary Completion Date :||June 2016|
|Actual Study Completion Date :||June 2016|
Normal Tension Glaucoma
Patients with manifest normal tension glaucoma
- Trans-lamina cribrosa pressure difference (TLCPD) [ Time Frame: 1 day Single time point measurement ]Difference between intraocular pressure (IOP) and intracranial pressure in different body positions
- Postural changes on blood flow velocity and cross-section area of right and left internal jugular veins (IJV) and external jugular veins (EJV) [ Time Frame: 1 day Single time point measurement ]
- Retinal perfusion using 3D Phase contrast magnetic resonance imaging (3DPCMRI) [ Time Frame: 1 day Single time point measurement ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02776449
|Umeå, Sweden, SE-901 85|
|Principal Investigator:||Jan Malm, MD||Umeå University|