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Neurovascular Coupling in Subjects With Amblyopia

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ClinicalTrials.gov Identifier: NCT01746693
Recruitment Status : Recruiting
First Posted : December 11, 2012
Last Update Posted : January 9, 2018
Sponsor:
Information provided by (Responsible Party):

Study Description
Brief 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. 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.


Condition or disease Intervention/treatment
Amblyopia ex Strabismus Amblyopia ex Anisometropia Device: Dynamic Vessel Analyzer Other: Laser Doppler Velocimetry Device: 7-Tesla MRI Other: Pattern electroretinography Other: Fourier domain optical coherence tomography

Study Design

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 60 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Neurovascular Coupling in Subjects With Amblyopia
Actual Study Start Date : March 2014
Estimated Primary Completion Date : January 2019
Estimated Study Completion Date : April 2019


Arms and Interventions

Arm Intervention/treatment
Experimental: amblyopia ex anisometropia
20 male and female volunteers with amblyopia ex anisometropia
Device: Dynamic Vessel Analyzer
retinal vessel diameter, retinal oxygen saturation
Other: Laser Doppler Velocimetry
retinal blood flow velocity, retinal blood flow
Device: 7-Tesla MRI
High resolution functional and anatomical imaging of the visual pathway
Other: Pattern electroretinography
inner retinal function
Other: Fourier domain optical coherence tomography
Blood flow in retina.
Experimental: amblyopia ex strabismus
20 male and female volunteers with amblyopia ex strabismus
Device: Dynamic Vessel Analyzer
retinal vessel diameter, retinal oxygen saturation
Other: Laser Doppler Velocimetry
retinal blood flow velocity, retinal blood flow
Device: 7-Tesla MRI
High resolution functional and anatomical imaging of the visual pathway
Other: Pattern electroretinography
inner retinal function
Other: Fourier domain optical coherence tomography
Blood flow in retina.
Experimental: control subjects
20 healthy male and female control subjects
Device: Dynamic Vessel Analyzer
retinal vessel diameter, retinal oxygen saturation
Other: Laser Doppler Velocimetry
retinal blood flow velocity, retinal blood flow
Device: 7-Tesla MRI
High resolution functional and anatomical imaging of the visual pathway
Other: Pattern electroretinography
inner retinal function
Other: Fourier domain optical coherence tomography
Blood flow in retina.


Outcome Measures

Primary Outcome Measures :
  1. Retinal Vessel Diameter in Response to Flickering Light (DVA) [ Time Frame: once on the study day ]

Secondary Outcome Measures :
  1. Retinal (arterial and venous) oxygen saturation [ Time Frame: once on the study day ]
  2. Retinal blood velocity in response to flickering light [ Time Frame: once on the study day ]
  3. High resolution functional and anatomical imaging of the visual pathway [ Time Frame: once on the study day ]
  4. Inner Retinal Function [ Time Frame: once on the study day ]

Eligibility Criteria

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 55 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • 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)

Exclusion Criteria:

  • 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
Contacts and Locations

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 ClinicalTrials.gov identifier (NCT number): NCT01746693


Contacts
Contact: Gerhard Garhoefer, MD +43140400 ext 2981 gerhard.garhoefer@meduniwien.ac.at

Locations
Austria
Department of Clinical Pharmacology, Medical University of Vienna Recruiting
Vienna, Austria, 1090
Contact: Gerhard Garhoefer, MD    +43140400 ext 2981    gerhard.garhoefer@meduniwien.ac.at   
Principal Investigator: Gerhard Garhoefer, MD         
Sponsors and Collaborators
Medical University of Vienna
More Information

Responsible Party: Gerhard Garhofer, Assoc. Prof. PD Dr., Medical University of Vienna
ClinicalTrials.gov Identifier: NCT01746693     History of Changes
Other Study ID Numbers: OPHT-291012
First Posted: December 11, 2012    Key Record Dates
Last Update Posted: January 9, 2018
Last Verified: January 2018

Keywords provided by Gerhard Garhofer, Medical University of Vienna:
retinal vessel diameter
retinal oxygen saturation
high resolution functional and anatomical imaging
inner retinal function
flicker response

Additional relevant MeSH terms:
Amblyopia
Strabismus
Anisometropia
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Vision Disorders
Sensation Disorders
Neurologic Manifestations
Eye Diseases
Signs and Symptoms
Ocular Motility Disorders
Cranial Nerve Diseases
Refractive Errors
Glucuronyl glucosamine glycan sulfate
Anticoagulants
Hypolipidemic Agents
Antimetabolites
Molecular Mechanisms of Pharmacological Action
Lipid Regulating Agents
Fibrinolytic Agents
Fibrin Modulating Agents
Hypoglycemic Agents
Physiological Effects of Drugs