HealthyNCT00571012
Aqueous Outflow Facility Changes With Posture
An observational study of Healthy, run by Mayo Clinic at 1 site in United States.
Trial summary
Intraocular pressure (IOP) varies with body position, with a significant increase occurring from the seated to the supine position. Previous research has indicated that the IOP increase cannot be explained by changes in episcleral venous pressure(blood flow leading away from the eye) alone. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- Oct 2007to Dec 2007
- Phase
- Observational
- 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 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Healthy young volunteers aged 18-45 will be recruited from Mayo Clinic employees and students, and local area residents.
Who may be able to join
- Healthy, aged 18-45.
- Subjects will be given a complete dilated eye exam and an updated medical history will be performed
Who cannot join
- IOP greater than 22mmHg
- Evidence of glaucomatous optic neuropathy
- Poor fixation
- Nystagmus
- Tropias
- Phorias
Show all 15Show fewer
- Recent infection
- Corneal scarring preventing reliable tonometry
- Evidence of pigment dispersion
- Narrow angles
- History of trauma or surgery
- Systemic use of beta blockers or steroids
- Diabetic eye disease, uveitis, high (>6D) myopia or high(>4D) hyperopia.
- Patients with chronic medical conditions(eg: hypertension) will be allowed to participate as long as their medical condition has been under good control over the preceding 12 months.
- Subjects will also need to have good cervical neck malleability and be able to meet the physical needs of the protocol which call for 4 minutes of neck extension.
Trial locations and contacts
1 site in 1 country.
About this study
Intraocular pressure (IOP) varies with body position, with a significant increase occurring from the seated to the supine position. Previous research has indicated that the IOP increase cannot be explained by changes in episcleral venous pressure(blood flow leading away from the eye) alone. As well, previous research has indicated that aqueous flow rate is independent of body position. The purpose of this project was to determine if aqueous humor outflow facility varied with changes in posture.
Read the detailed description
On the day of the experiment, patients will be asked to maintain a regular schedule and normal activities. This will include avoiding excess caffeine intake, large deviations from normal sleep cycle, or exposure to pharmacologic IOP modifying agents.
Subjects will be seated in standard ophthalmologic examining chairs and reclined into the supine position in a quiet room with subdued lighting for approximately 5 minutes. Anesthesia will be achieved by instilling 3-4 drops of 0.5% proparacaine. The contralateral eye will be patched in an air-tight fashion with an adhesive eye patch to reduce evaporative losses and drying of the cornea. The patient will be asked to keep eyes closed prior to start of measurements. When ready, the patient will be asked to open their eyes and to observe a dim fixation target that will be placed on the ceiling of the room, roughly 6 feet from the patient's eyes. Baseline IOP (Po) will be measured using a pneumatonometer (Model 30 Classic Mentor). Tonography will then be performed using the electronic Schiotz tonometer with a 10g weight in order to obtain a four minute tracing. The procedure will then be repeated on the contralateral eye, with patching of the already tested eye. After this, the patient's chair will the be raised 70 degrees and patient will be asked to hyperextend their neck until their cornea is parallel to the floor. A minimum of 30 minutes will be allowed to elapse, allowing for autonomic, postural and hormonal changes to stabilize. Then a repeat baseline IOP for the sitting position will be taken and another 4 minute tracing will be collected successively in each eye as described above.
Data from the tonometer tracing will be collected electronically and will be exported to a standard Excel file. A smooth curve of best fit will be established through each tonogram once graphed, correcting for oscillations and drift. This curve will help determine the adequacy of the collected sample. Tracings that have a poorly fitted curve might occur for a variety of reasons including patient tenseness and anxiety, uncontrollable tendency to fall asleep and incidental interruptions such as a sudden wave of intestinal peristalsis. Corresponding "Po" values for the initial steady-state IOP and the "C" value for facility of aqueous outflow will be gathered by referring to standard tables and normograms.
The main potential risk of participating in the study is the possibility of corneal abrasion. Previous studies at the Mayo Clinic using the same techniques did not result in any corneal abrasions in over 300 eyes of more than 150 patients. Based on this result, we estimate the risk of a corneal abrasion to be minimal. If a corneal abrasion occurs, the patient will be removed from the study. The patient will be treated with antibiotic drops or ointment and followed until the abrasion has completely healed.
Other minor risks include possible allergic reaction to the anesthetic drops or the adhesive glue. As with any medication, allergic reactions are a possibility. However, these will be the same drops used in routine clinical practice, and allergic reaction is extremely uncommon.
- Conditions
- Healthy
- Keywords
- glaucoma, outflow facility, Healthy eye function
- Medical subject headings
- Glaucoma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Only one group- A | Healthy young subjects aged 18-45. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Looking for change in outflow facility with change in position
Measured: 4 minutes per position
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Dec 2007 (estimated)
- Study startOct 2007
- Primary completionDec 2007
- Study completionDec 2007
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by Mayo ClinicThe 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
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mayo Clinic
- Sponsor type
- University, hospital or other
- Investigators
- Deepan Selvadurai, MD, Principal investigator, Mayo Clinic
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00571012
- Sponsor's protocol ID
- 07-006662
- Status last verified
- Nov 2009
- First submitted
- 7 Dec 2007
- Last updated
- 26 Nov 2009
- Results posted
- No
- Data monitoring committee
- No
Publications
GALIN MA, McIVOR JW, MAGRUDER GB. Influence of position on intraocular pressure. Am J Ophthalmol. 1963 Apr;55:720-3. No abstract available.
PubMed 13960329
Study at a glance
From the registry record, last updated by the sponsor on 26 Nov 2009. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Aqueous Outflow Facility Changes With Posture
- ClinicalTrials.gov ID
- NCT00571012
- Acronym / sponsor ID
- 07-006662
- Conditions
- Healthy
- Keywords
- glaucoma, outflow facility, Healthy eye function
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- Mayo ClinicUniversity, hospital or other
- Study start
- Oct 2007
- Primary completion
- Dec 2007 (actual)
- Study completion
- Dec 2007 (actual)
- First posted
- 11 Dec 2007 (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.
Intraocular pressure (IOP) varies with body position, with a significant increase occurring from the seated to the supine position. Previous research has indicated that the IOP increase cannot be explained by changes in episcleral venous pressure(blood flow leading away from the eye) alone. As well, previous research has indicated that aqueous flow rate is independent of body position. The purpose of this project was to determine if aqueous humor outflow facility varied with changes in posture.
Detailed description
On the day of the experiment, patients will be asked to maintain a regular schedule and normal activities. This will include avoiding excess caffeine intake, large deviations from normal sleep cycle, or exposure to pharmacologic IOP modifying agents.
Subjects will be seated in standard ophthalmologic examining chairs and reclined into the supine position in a quiet room with subdued lighting for approximately 5 minutes. Anesthesia will be achieved by instilling 3-4 drops of 0.5% proparacaine. The contralateral eye will be patched in an air-tight fashion with an adhesive eye patch to reduce evaporative losses and drying of the cornea. The patient will be asked to keep eyes closed prior to start of measurements. When ready, the patient will be asked to open their eyes and to observe a dim fixation target that will be placed on the ceiling of the room, roughly 6 feet from the patient's eyes. Baseline IOP (Po) will be measured using a pneumatonometer (Model 30 Classic Mentor). Tonography will then be performed using the electronic Schiotz tonometer with a 10g weight in order to obtain a four minute tracing. The procedure will then be repeated on the contralateral eye, with patching of the already tested eye. After this, the patient's chair will the be raised 70 degrees and patient will be asked to hyperextend their neck until their cornea is parallel to the floor. A minimum of 30 minutes will be allowed to elapse, allowing for autonomic, postural and hormonal changes to stabilize. Then a repeat baseline IOP for the sitting position will be taken and another 4 minute tracing will be collected successively in each eye as described above.
Data from the tonometer tracing will be collected electronically and will be exported to a standard Excel file. A smooth curve of best fit will be established through each tonogram once graphed, correcting for oscillations and drift. This curve will help determine the adequacy of the collected sample. Tracings that have a poorly fitted curve might occur for a variety of reasons including patient tenseness and anxiety, uncontrollable tendency to fall asleep and incidental interruptions such as a sudden wave of intestinal peristalsis. Corresponding "Po" values for the initial steady-state IOP and the "C" value for facility of aqueous outflow will be gathered by referring to standard tables and normograms.
The main potential risk of participating in the study is the possibility of corneal abrasion. Previous studies at the Mayo Clinic using the same techniques did not result in any corneal abrasions in over 300 eyes of more than 150 patients. Based on this result, we estimate the risk of a corneal abrasion to be minimal. If a corneal abrasion occurs, the patient will be removed from the study. The patient will be treated with antibiotic drops or ointment and followed until the abrasion has completely healed.
Other minor risks include possible allergic reaction to the anesthetic drops or the adhesive glue. As with any medication, allergic reactions are a possibility. However, these will be the same drops used in routine clinical practice, and allergic reaction is extremely uncommon.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Only one group- A | – | –Healthy young subjects aged 18-45. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Healthy young volunteers aged 18-45 will be recruited from Mayo Clinic employees and students, and local area residents.
Key inclusion criteria (2 listed)
- Healthy, aged 18-45.
- Subjects will be given a complete dilated eye exam and an updated medical history will be performed
Key exclusion criteria (15 listed)
- IOP greater than 22mmHg
- Evidence of glaucomatous optic neuropathy
- Poor fixation
- Nystagmus
- Tropias
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Looking for change in outflow facility with change in position
Time frame: 4 minutes per position
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Nov 2009.
- Background: PubMed 13960329GALIN MA, McIVOR JW, MAGRUDER GB. Influence of position on intraocular pressure. Am J Ophthalmol. 1963 Apr;55:720-3. No abstract available.
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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.
Deepan Selvadurai, MD principal investigator
Mayo Clinic
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Healthy, run by Mayo Clinic at 1 site in United States.
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 2 inclusion and 15 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: finished, as of the sponsor's last update on 26 Nov 2009. 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 United States. 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 is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Looking for change in outflow facility with change in position (time frame: 4 minutes per position). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00571012, which also lists 1 linked publication.
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 26 Nov 2009.