Neurovascular Coupling in Subjects With Amblyopia
1 other identifier
interventional
60
1 country
1
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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P25-P50 for not_applicable
Started Mar 2014
Longer than P75 for not_applicable
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
December 7, 2012
CompletedFirst Posted
Study publicly available on registry
December 11, 2012
CompletedStudy Start
First participant enrolled
March 1, 2014
CompletedPrimary Completion
Last participant's last visit for primary outcome
September 1, 2023
CompletedStudy Completion
Last participant's last visit for all outcomes
September 2, 2023
CompletedApril 7, 2022
April 1, 2022
9.5 years
December 7, 2012
April 6, 2022
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
Retinal Vessel Diameter in Response to Flickering Light (DVA)
once on the study day
Secondary Outcomes (4)
Retinal (arterial and venous) oxygen saturation
once on the study day
Retinal blood velocity in response to flickering light
once on the study day
High resolution functional and anatomical imaging of the visual pathway
once on the study day
Inner Retinal Function
once on the study day
Study Arms (3)
amblyopia ex anisometropia
EXPERIMENTAL20 male and female volunteers with amblyopia ex anisometropia
amblyopia ex strabismus
EXPERIMENTAL20 male and female volunteers with amblyopia ex strabismus
control subjects
EXPERIMENTAL20 healthy male and female control subjects
Interventions
retinal vessel diameter, retinal oxygen saturation
retinal blood flow velocity, retinal blood flow
High resolution functional and anatomical imaging of the visual pathway
inner retinal function
Blood flow in retina.
Eligibility Criteria
You may qualify if:
- 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)
You may not qualify if:
- 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
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, 1090, Austria
MeSH Terms
Interventions
Intervention Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- NON RANDOMIZED
- Masking
- SINGLE
- Who Masked
- OUTCOMES ASSESSOR
- Purpose
- BASIC SCIENCE
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Assoc. Prof. PD Dr.
Study Record Dates
First Submitted
December 7, 2012
First Posted
December 11, 2012
Study Start
March 1, 2014
Primary Completion
September 1, 2023
Study Completion
September 2, 2023
Last Updated
April 7, 2022
Record last verified: 2022-04