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Neurovascular Coupling in Subjects With Amblyopia

This study is currently recruiting participants. (see Contacts and Locations)
Verified November 2014 by Medical University of Vienna
Sponsor:
Information provided by (Responsible Party):
Gerhard Garhofer, Medical University of Vienna
ClinicalTrials.gov Identifier:
NCT01746693
First received: December 7, 2012
Last updated: November 12, 2014
Last verified: November 2014

December 7, 2012
November 12, 2014
February 2014
December 2015   (final data collection date for primary outcome measure)
Retinal Vessel Diameter in Response to Flickering Light (DVA) [ Time Frame: once on the study day ] [ Designated as safety issue: No ]
Same as current
Complete list of historical versions of study NCT01746693 on ClinicalTrials.gov Archive Site
  • Retinal (arterial and venous) oxygen saturation [ Time Frame: once on the study day ] [ Designated as safety issue: No ]
  • Retinal blood velocity in response to flickering light [ Time Frame: once on the study day ] [ Designated as safety issue: No ]
  • High resolution functional and anatomical imaging of the visual pathway [ Time Frame: once on the study day ] [ Designated as safety issue: No ]
  • Inner Retinal Function [ Time Frame: once on the study day ] [ Designated as safety issue: No ]
Same as current
Not Provided
Not Provided
 
Neurovascular Coupling in Subjects With Amblyopia
Neurovascular Coupling in Subjects With Amblyopia

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.

Not Provided
Interventional
Not Provided
Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Basic Science
  • Amblyopia ex Strabismus
  • 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
  • Experimental: amblyopia ex anisometropia
    20 male and female volunteers with amblyopia ex anisometropia
    Interventions:
    • Device: Dynamic Vessel Analyzer
    • Other: Laser Doppler Velocimetry
    • Device: 7-Tesla MRI
    • Other: Pattern electroretinography
  • Experimental: amblyopia ex strabismus
    20 male and female volunteers with amblyopia ex strabismus
    Interventions:
    • Device: Dynamic Vessel Analyzer
    • Other: Laser Doppler Velocimetry
    • Device: 7-Tesla MRI
    • Other: Pattern electroretinography
  • Experimental: control subjects
    20 healthy male and female control subjects
    Interventions:
    • Device: Dynamic Vessel Analyzer
    • Other: Laser Doppler Velocimetry
    • Device: 7-Tesla MRI
    • Other: Pattern electroretinography
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruiting
60
January 2016
December 2015   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Men and women aged between 18 and 35 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
Both
18 Years to 35 Years
Yes
Contact: Gerhard Garhoefer, MD +43140400 ext 2981 gerhard.garhoefer@meduniwien.ac.at
Austria
 
NCT01746693
OPHT-291012
Yes
Gerhard Garhofer, Medical University of Vienna
Medical University of Vienna
Not Provided
Not Provided
Medical University of Vienna
November 2014

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP