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Measurement of Total Retinal Blood Flow During Flicker Stimulation in Healthy Subjects

NCT02531399 — Not applicable, Completed, 20 participants, Medical University of Vienna

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RegistryNCT02531399
StatusCompleted
PhaseNot applicable
Study typeInterventional; na, single group, masking: none, basic science
Enrollment20 (Actual)
SponsorMedical University of Vienna (Other)
ConditionsHealthy
InterventionsFDOCT, LDV, DVA, LSFG (Device)
Datesstart 2015-10-01, primary completion 2017-08-01, completion 2017-09-01, first posted 2015-08-24, last updated 2017-09-06
Locations1 site in Austria

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-Summary

Neurovascular coupling or functional hyperemia is defined as an essential physiologic mechanism in the brain, which is necessary for the local adaption of blood flow to altered metabolic demands of the tissue. It has been shown that also in the eye, blood flow is considerably coupled to retinal neural activity. The current concept of functional hyperemia is that visual stimulation, as flicker light, effectuates increasing neural activity in the retina, which elevates the metabolic needs of the retinal tissue for oxygen and glucose and consequently induces dilatation and augmented blood flow in the retinal vasculature. In several studies, stimulation with flicker light has been shown to induce an increase of blood flow in major retinal arteries and veins as well as an increase of optic nerve head blood flow. Up until now, flicker induced changes in blood flow were measured solely in the major retinal arteries and veins with systems such as the commercially available dynamic vessel analyzer (DVA) by Imedos and with laser Doppler velocimetry (LDV).

In the present study, the investigators propose to measure the response of total retinal blood flow to diffuse luminance flicker stimulation with bi-directional Fourier Domain Doppler Optical Coherence Tomography (FDOCT) as well as with Laser Speckle Flowgraphy (LSFG) in healthy subjects by assessing vessel diameter, blood velocity and blood flow of all retinal vessels. For comparative reasons, the investigators will furthermore assess the blood flow of major retinal arteries and veins with the dynamic vessel analyzer (DVA) and laser Doppler velocimetry (LDV).

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+Arms and interventions

ArmTypeInterventionsDescription
Healthy SubjectsExperimentalDevice: FDOCT; Device: LDV; Device: DVA; Device: LSFG20 healthy female and male volunteers, age 18-45 years, non-smokers. Measurements with FDOCT, DVA, LDV and LSFG will be done in all healthy subjects.
  • FDOCT (Device), also known as Fourier Domain Color Doppler Optical Coherence Tomography: Measurement of retinal blood velocities
  • LDV (Device), also known as Laser Doppler Velocimetry: Measurement of retinal blood velocities
  • DVA (Device), also known as Dynamic Vessel Analyzer: Measurement of retinal vessel diameters
  • LSFG (Device), also known as Laser Speckle Flowgraphy: Imaging of retinal blood flow

+Outcome measures

Primary outcomes

  • Flicker induced changes in total retinal blood flow (FDOCT) [1 day]

Secondary outcomes

  • Red blood cell velocity (LDV) [1 day]
  • Retinal vessel diameters (DVA) [1 day]
  • Retinal oxygen saturation (DVA) [1 day]
  • Relative Flow Volume (LSFG) [1 day]

+Eligibility

Sex: All, ages: 18 Years to 45 Years, accepts healthy volunteers

Inclusion Criteria:

* Informed consent for participation
* Men and women aged between 18 and 45 years
* Non-smokers
* Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
* Systolic blood pressure < 140 mmHg, diastolic blood pressure < 90 mmHg
* Normal ophthalmic findings, ametropia less than 3 diopters

Exclusion Criteria:

* History or presence of ocular disease
* Ametropy ≥ 3 dpt
* Treatment with any drug in the 3 weeks preceding the first study day
* Symptoms of a clinically relevant illness in the 3 weeks before the first study day
* Participation in a clinical trial in the 3 weeks preceding the first study day
* Blood donation during the 3 weeks preceding the first study day
* History of family history of epilepsy
* Abuse of alcoholic beverages
* Pregnancy

+Locations (1)

FacilityCityCountryStatus
Department of Clinical Pharmacology, Medical University of Vienna, AustriaViennaAustria

+Publications

  • Results publication: Fondi K, Aschinger GC, Bata AM, Wozniak PA, Liao L, Seidel G, Doblhoff-Dier V, Schmidl D, Garhofer G, Werkmeister RM, Schmetterer L. Measurement of Retinal Vascular Caliber From Optical Coherence Tomography Phase Images. Invest Ophthalmol Vis Sci. 2016 Jul 1;57(9):OCT121-9. doi: 10.1167/iovs.15-18476. PMID 27409462

+Investigators

  • Gerhard Garhoefer, MD, Principal investigator, Department of Clinical Pharmacology, Medical University of Vienna

My Notes