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Pressure Difference Between Brain and Eye: a Possible Cause to Normal Tension Glaucoma.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02776449
Recruitment Status : Completed
First Posted : May 18, 2016
Last Update Posted : May 3, 2017
Västerbotten County Council, Sweden
Information provided by (Responsible Party):
Umeå University

Brief Summary:
The main aim of this study is to determine the trans-laminal cribrosa pressure difference (TLCPD) for normal tension glaucoma (NTG) patients from the brain and the eye in supine, upright and minor head down tilt positions. It is also to investigate the venous drainage system in the same body positions.

Condition or disease
Normal Tension Glaucoma

Detailed Description:

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.

  1. 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.
  2. 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.
  3. 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.

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Study Type : Observational
Actual Enrollment : 17 participants
Observational Model: Case-Only
Time Perspective: Prospective
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

Resource links provided by the National Library of Medicine

Normal Tension Glaucoma
Patients with manifest normal tension glaucoma

Primary Outcome Measures :
  1. 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

Secondary Outcome Measures :
  1. 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 ]

Other Outcome Measures:
  1. Retinal perfusion using 3D Phase contrast magnetic resonance imaging (3DPCMRI) [ Time Frame: 1 day Single time point measurement ]

Information from the National Library of Medicine

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Ages Eligible for Study:   40 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Normal tension glaucoma patients

Inclusion Criteria:

  • Subject has normal tension glaucoma in one or both eyes (glaucomatous optic nerve head and corresponding visual field defects)
  • Intraocular pressures before treatment did not exceed 21 mmHg. Occasional measurement up to 24 is accepted.

Exclusion Criteria:

  • History of brain disease or brain surgery
  • History of other neurologic or ocular disease causing visual field loss
  • Use of anticoagulants other than acetylsalicylic acid
  • Use of carbonic anhydrase inhibitors
  • Previous lumbar puncture
  • Claustrophobia

Information from the National Library of Medicine

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 identifier (NCT number): NCT02776449

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Umeå University
Umeå, Sweden, SE-901 85
Sponsors and Collaborators
Umeå University
Västerbotten County Council, Sweden
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Principal Investigator: Jan Malm, MD Umeå University

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Umeå University Identifier: NCT02776449     History of Changes
Other Study ID Numbers: NTG-ICP_1
First Posted: May 18, 2016    Key Record Dates
Last Update Posted: May 3, 2017
Last Verified: May 2016
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Additional relevant MeSH terms:
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Low Tension Glaucoma
Ocular Hypertension
Eye Diseases
Optic Nerve Diseases