HealthyNCT00915226
Regulation of Optic Nerve Head Blood Flow During Combined Changes in Intraocular Pressure and Arterial Blood Pressure
A study testing Suction cup application and Squatting in people with Healthy, run by Medical University of Vienna at 1 site in Austria.
Trial summary
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. The existence of an effective autoregulation in the optic nerve head (ONH) circulation has been shown in animals and humans. Read more about this study
- Who is it for?
- Ages 19 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- Suction cup application and Squatting
- Type of treatment
- Surgery or procedure
- How many people
- 0 participants
- Where
- 1 siteAustria
- Study dates
- Sep 2009to Oct 2010
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile (Must et al. 1991)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropia < 1 Dpt
Who cannot join
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- Blood donation during the previous 3 weeks
- Presence of intraocular pathology: ocular hypertension, glaucoma, retinal vasculopathy or other retinal diseases
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, 1090
About this study
Official title: Regulation of Optic Nerve Head Blood Flow During Combined Changes in Intraocular Pressure and Arterial Blood Pressure.
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. The existence of an effective autoregulation in the optic nerve head (ONH) circulation has been shown in animals and humans. Moderate elevation of intraocular pressure (IOP) caused only slight effect on ONH blood flow in monkeys, cats and rabbits. In humans, during an artificial IOP rise using a suction cup method the ONH blood flow maintains almost constant until IOP reaches 40-55 mmHg. During isometric exercise the upper limit of autoregulation appears to be approximately 40% above the baseline ocular perfusion pressure. The mechanism behind ONH blood flow autoregulation is still unknown. The present experiments are designed to improve the investigators' knowledge of the physiology of regulatory mechanisms in ONH circulation, which may be helpful for a better understanding of blood flow abnormalities in glaucoma. This is of importance, because there is an increased evidence, that vascular dysregulation plays a role in the development of glaucomatous damage.
- Conditions
- Healthy
- Being tested
- Suction cup application, Squatting
- Keywords
- Optic disk, Regional blood flow, Autoregulation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Suction cup applicationProcedure or surgery
The IOP will be raised by an 11 mm diameter, standardized suction cup placed on the temporal sclera with the anterior edge at least 1 mm from the limbus.
SquattingProcedure or surgery
Squatting
What is being measured
The primary outcome is the main question the study is designed to answer.
Ocular perfusion pressure - ONH blood flow relationship
Measured: 9 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jun 2009 (estimated)
- Study startSep 2009
- Primary completionJun 2010
- Study completionOct 2010
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gerhard Garhofer, Medical University of Vienna
- Investigators
- Elzbieta Polska, MD, Study director, Department of Clinical Pharmacology, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00915226
- Sponsor's protocol ID
- OPHT-310505-2
- Status last verified
- Nov 2014
- First submitted
- 3 Jun 2009
- Last updated
- 14 Nov 2014
- Results posted
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Nov 2014. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Regulation of Optic Nerve Head Blood Flow During Combined Changes in Intraocular Pressure and Arterial Blood Pressure.
- ClinicalTrials.gov ID
- NCT00915226
- Acronym / sponsor ID
- OPHT-310505-2
- Conditions
- Healthy
- Keywords
- Optic disk, Regional blood flow, Autoregulation
- Study type
- Interventional
- Recruitment status
- Withdrawn
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- Sep 2009
- Primary completion
- Jun 2010 (actual)
- Study completion
- Oct 2010 (actual)
- First posted
- 5 Jun 2009 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. The existence of an effective autoregulation in the optic nerve head (ONH) circulation has been shown in animals and humans. Moderate elevation of intraocular pressure (IOP) caused only slight effect on ONH blood flow in monkeys, cats and rabbits. In humans, during an artificial IOP rise using a suction cup method the ONH blood flow maintains almost constant until IOP reaches 40-55 mmHg. During isometric exercise the upper limit of autoregulation appears to be approximately 40% above the baseline ocular perfusion pressure. The mechanism behind ONH blood flow autoregulation is still unknown. The present experiments are designed to improve the investigators' knowledge of the physiology of regulatory mechanisms in ONH circulation, which may be helpful for a better understanding of blood flow abnormalities in glaucoma. This is of importance, because there is an increased evidence, that vascular dysregulation plays a role in the development of glaucomatous damage.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
Who may qualify
- Ages
- 19 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile (Must et al. 1991)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropia < 1 Dpt
Key exclusion criteria (5 listed)
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- Blood donation during the previous 3 weeks
- Presence of intraocular pathology: ocular hypertension, glaucoma, retinal vasculopathy or other retinal diseases
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Suction cup applicationThe IOP will be raised by an 11 mm diameter, standardized suction cup placed on the temporal sclera with the anterior edge at least 1 mm from the limbus. | Procedure or surgery | – |
| SquattingSquatting | Procedure or surgery | – |
Primary outcome
Ocular perfusion pressure - ONH blood flow relationship
Time frame: 9 months
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Nov 2014.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Elzbieta Polska, MD study director
Department of Clinical Pharmacology, Medical University of Vienna
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Suction cup application and Squatting in people with Healthy, run by Medical University of Vienna at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 14 Nov 2014. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Ocular perfusion pressure - ONH blood flow relationship (time frame: 9 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Nov 2014.