Amblyopia ex StrabismusNCT01746693
Neurovascular Coupling in Subjects With Amblyopia
A study testing Dynamic Vessel Analyzer, Laser Doppler Velocimetry and 7-Tesla MRI in people with Amblyopia ex Strabismus and Amblyopia ex Anisometropia, run by Medical University of Vienna at 1 site in Austria.
Trial summary
Amblyopia is a developmental condition that is characterized by reduced vision of the eye due to the presence of a sensory impediment during visual development, such as strabismus (ocular misalignment) or anisometropia (unequal refractive error), occurring early in life. Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Amblyopia ex Strabismus, Amblyopia ex Anisometropia
- What is being tested?
- Dynamic Vessel Analyzer, Laser Doppler Velocimetry and 7-Tesla MRI
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteAustria
- Study dates
- Mar 2014to 2 Sep 2023
- 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 18 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men and women aged between 18 and 55 years
- Non-smokers (for at least 6 months)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings except amblyopia on one eye resulting from anisometropia or strabismus with a visual acuity of Snellen ≤ 0.3 with best correction on the amblyopic eye and Snellen 0.9 or better in the contralateral eye (for subjects with amblyopia)
- Normal ophthalmic findings with visual acuity of Snellen ≥ 1.0 in both eyes (for control subjects)
Who cannot join
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- Presence or history of a severe medical condition as judged by the clinical investigator
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study (except oral contraceptives)
- Blood donation during the previous three weeks
- Pregnancy, planned pregnancy or lactating
- Any metallic, electric, electronic or magnetic device or object not removable except dental fillings
- Claustrophobia
- Epilepsia, history or family history of seizures
Trial locations and contacts
1 site in 1 country.
Austria1 site, 1 recruiting
- Recruiting
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, 1090
Gerhard Garhoefer, MD, +43140400 ext. 2981, gerhard.garhoefer@meduniwien.ac.at
Gerhard Garhoefer, MD
About this study
Amblyopia is a developmental condition that is characterized by reduced vision of the eye due to the presence of a sensory impediment during visual development, such as strabismus (ocular misalignment) or anisometropia (unequal refractive error), occurring early in life. Recent studies in humans and animals point towards a cortical locus for the processing deficit in amblyopia, revealing sensory deficits at the signal cell level. If changes in retinal neuronal function are also present, is unknown.
Like in the brain, blood flow in the retina is coupled to neuronal activity. This phenomenon has been measured by different study groups with non invasive techniques in the brain and retina. It has been shown in previous studies that stimulating the retina with diffuse luminant flickering light increases retinal vessel diameter and blood flow. However, it is unknown whether this is also the case in the retina of amblyopic eyes. Additionally, the introduction of blood oxygen level dependent (BOLD) fMRI also makes it possible to directly access the vascular response in the brain to visual stimuli.
Therefore, the aim of the present study is to investigate the effect of luminant flickering light on retinal vessel diameter and retinal blood flow in subjects with amblyopia. Also, oxygen saturation in retinal vessels will be assessed as well as pattern ERG for assessment of retinal function. Additionally, a high resolution image of the visual pathway will be taken with 7 Tesla MRI to investigate whether anatomical or functional alterations are present.
- Being tested
- Dynamic Vessel Analyzer, Laser Doppler Velocimetry, 7-Tesla MRI, Pattern electroretinography, Fourier domain optical coherence tomography
- Keywords
- retinal vessel diameter, retinal oxygen saturation, high resolution functional and anatomical imaging, inner retinal function, flicker response
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dynamic Vessel AnalyzerDevice
retinal vessel diameter, retinal oxygen saturation
Laser Doppler VelocimetryOther
retinal blood flow velocity, retinal blood flow
7-Tesla MRIDevice
High resolution functional and anatomical imaging of the visual pathway
Pattern electroretinographyOther
inner retinal function
Fourier domain optical coherence tomographyOther
Blood flow in retina.
| Study group | Role | What they receive |
|---|---|---|
| amblyopia ex anisometropia | Experimental | 20 male and female volunteers with amblyopia ex anisometropia Receives: Device: Dynamic Vessel Analyzer; Other: Laser Doppler Velocimetry; Device: 7-Tesla MRI; Other: Pattern electroretinography; Other: Fourier domain optical coherence tomography |
| amblyopia ex strabismus | Experimental | 20 male and female volunteers with amblyopia ex strabismus Receives: Device: Dynamic Vessel Analyzer; Other: Laser Doppler Velocimetry; Device: 7-Tesla MRI; Other: Pattern electroretinography; Other: Fourier domain optical coherence tomography |
| control subjects | Experimental | 20 healthy male and female control subjects Receives: Device: Dynamic Vessel Analyzer; Other: Laser Doppler Velocimetry; Device: 7-Tesla MRI; Other: Pattern electroretinography; Other: Fourier domain optical coherence tomography |
What is being measured
The primary outcome is the main question the study is designed to answer.
Retinal Vessel Diameter in Response to Flickering Light (DVA)
Measured: once on the study day
Secondary outcomes (4)
Retinal (arterial and venous) oxygen saturation
Measured: once on the study day
Retinal blood velocity in response to flickering light
Measured: once on the study day
High resolution functional and anatomical imaging of the visual pathway
Measured: once on the study day
Inner Retinal Function
Measured: once on the study day
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Dec 2012 (estimated)
- Study startMar 2014
- Primary completionSep 2023 (estimated)
- Study completion2 Sep 2023 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Amblyopia ex StrabismusStudies 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
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 60 participants (estimated)
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
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01746693
- Sponsor's protocol ID
- OPHT-291012
- Status last verified
- Apr 2022
- First submitted
- 7 Dec 2012
- Last updated
- 7 Apr 2022
- Results posted
- No
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 7 Apr 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Neurovascular Coupling in Subjects With Amblyopia
- ClinicalTrials.gov ID
- NCT01746693
- Acronym / sponsor ID
- OPHT-291012
- Keywords
- retinal vessel diameter, retinal oxygen saturation, high resolution functional and anatomical imaging, inner retinal function, flicker response
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- Mar 2014 (actual)
- Primary completion
- Sep 2023 (estimated)
- Study completion
- 2 Sep 2023 (estimated)
- First posted
- 11 Dec 2012 (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.
Amblyopia is a developmental condition that is characterized by reduced vision of the eye due to the presence of a sensory impediment during visual development, such as strabismus (ocular misalignment) or anisometropia (unequal refractive error), occurring early in life. Recent studies in humans and animals point towards a cortical locus for the processing deficit in amblyopia, revealing sensory deficits at the signal cell level. If changes in retinal neuronal function are also present, is unknown.
Like in the brain, blood flow in the retina is coupled to neuronal activity. This phenomenon has been measured by different study groups with non invasive techniques in the brain and retina. It has been shown in previous studies that stimulating the retina with diffuse luminant flickering light increases retinal vessel diameter and blood flow. However, it is unknown whether this is also the case in the retina of amblyopic eyes. Additionally, the introduction of blood oxygen level dependent (BOLD) fMRI also makes it possible to directly access the vascular response in the brain to visual stimuli.
Therefore, the aim of the present study is to investigate the effect of luminant flickering light on retinal vessel diameter and retinal blood flow in subjects with amblyopia. Also, oxygen saturation in retinal vessels will be assessed as well as pattern ERG for assessment of retinal function. Additionally, a high resolution image of the visual pathway will be taken with 7 Tesla MRI to investigate whether anatomical or functional alterations are present.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| amblyopia ex anisometropia | Experimental | Device: Dynamic Vessel Analyzer, Other: Laser Doppler Velocimetry, Device: 7-Tesla MRI, Other: Pattern electroretinography, Other: Fourier domain optical coherence tomography20 male and female volunteers with amblyopia ex anisometropia |
| amblyopia ex strabismus | Experimental | Device: Dynamic Vessel Analyzer, Other: Laser Doppler Velocimetry, Device: 7-Tesla MRI, Other: Pattern electroretinography, Other: Fourier domain optical coherence tomography20 male and female volunteers with amblyopia ex strabismus |
| control subjects | Experimental | Device: Dynamic Vessel Analyzer, Other: Laser Doppler Velocimetry, Device: 7-Tesla MRI, Other: Pattern electroretinography, Other: Fourier domain optical coherence tomography20 healthy male and female control subjects |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Men and women aged between 18 and 55 years
- Non-smokers (for at least 6 months)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings except amblyopia on one eye resulting from anisometropia or strabismus with a visual acuity of Snellen ≤ 0.3 with best correction on the amblyopic eye and Snellen 0.9 or better in the contralateral eye (for subjects with amblyopia)
- Normal ophthalmic findings with visual acuity of Snellen ≥ 1.0 in both eyes (for control subjects)
Key exclusion criteria (8 listed)
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- Presence or history of a severe medical condition as judged by the clinical investigator
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study (except oral contraceptives)
- Blood donation during the previous three weeks
- Pregnancy, planned pregnancy or lactating
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 |
|---|---|---|
| Dynamic Vessel Analyzerretinal vessel diameter, retinal oxygen saturation | Device | amblyopia ex anisometropia, amblyopia ex strabismus, control subjects |
| Laser Doppler Velocimetryretinal blood flow velocity, retinal blood flow | Other | amblyopia ex anisometropia, amblyopia ex strabismus, control subjects |
| 7-Tesla MRIHigh resolution functional and anatomical imaging of the visual pathway | Device | amblyopia ex anisometropia, amblyopia ex strabismus, control subjects |
| Pattern electroretinographyinner retinal function | Other | amblyopia ex anisometropia, amblyopia ex strabismus, control subjects |
| Fourier domain optical coherence tomographyBlood flow in retina. | Other | amblyopia ex anisometropia, amblyopia ex strabismus, control subjects |
Primary outcome
Retinal Vessel Diameter in Response to Flickering Light (DVA)
Time frame: once on the study day
4 secondary outcomes
Retinal (arterial and venous) oxygen saturation
Time frame: once on the study day
Retinal blood velocity in response to flickering light
Time frame: once on the study day
High resolution functional and anatomical imaging of the visual pathway
Time frame: once on the study day
Inner Retinal Function
Time frame: once on the study day
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Apr 2022.
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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Dynamic Vessel Analyzer, Laser Doppler Velocimetry and 7-Tesla MRI in people with Amblyopia ex Strabismus and Amblyopia ex Anisometropia, 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 5 inclusion and 8 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: status not confirmed, as of the sponsor's last update on 7 Apr 2022. 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?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Gerhard Garhoefer, MD (+43140400 ext. 2981, gerhard.garhoefer@meduniwien.ac.at), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Retinal Vessel Diameter in Response to Flickering Light (DVA) (time frame: once on the study day). 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 7 Apr 2022; AzTrials last refreshed its copy on 30 Oct 2026.