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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 : February 20, 2020
Sponsor:
Information provided by (Responsible Party):
Gerhard Garhofer, Medical University of Vienna

Tracking Information
First Submitted Date  ICMJE December 7, 2012
First Posted Date  ICMJE December 11, 2012
Last Update Posted Date February 20, 2020
Actual Study Start Date  ICMJE March 2014
Estimated Primary Completion Date December 2020   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: December 7, 2012)
Retinal Vessel Diameter in Response to Flickering Light (DVA) [ Time Frame: once on the study day ]
Original Primary Outcome Measures  ICMJE Same as current
Change History
Current Secondary Outcome Measures  ICMJE
 (submitted: December 7, 2012)
  • 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 ]
Original Secondary Outcome Measures  ICMJE Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE Neurovascular Coupling in Subjects With Amblyopia
Official Title  ICMJE Neurovascular Coupling in Subjects With Amblyopia
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.

Detailed Description Not Provided
Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Basic Science
Condition  ICMJE
  • Amblyopia ex Strabismus
  • Amblyopia ex Anisometropia
Intervention  ICMJE
  • 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.
Study Arms  ICMJE
  • 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
    • Other: Fourier domain optical coherence tomography
  • 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
    • Other: Fourier domain optical coherence tomography
  • 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
    • Other: Fourier domain optical coherence tomography
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Recruiting
Estimated Enrollment  ICMJE
 (submitted: December 7, 2012)
60
Original Estimated Enrollment  ICMJE Same as current
Estimated Study Completion Date  ICMJE December 2020
Estimated Primary Completion Date December 2020   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

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
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years to 55 Years   (Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE
Contact: Gerhard Garhoefer, MD +43140400 ext 2981 gerhard.garhoefer@meduniwien.ac.at
Listed Location Countries  ICMJE Austria
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT01746693
Other Study ID Numbers  ICMJE OPHT-291012
Has Data Monitoring Committee Yes
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Responsible Party Gerhard Garhofer, Medical University of Vienna
Study Sponsor  ICMJE Medical University of Vienna
Collaborators  ICMJE Not Provided
Investigators  ICMJE Not Provided
PRS Account Medical University of Vienna
Verification Date February 2020

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