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

NCT ID: NCT02531399

Last Updated: 2017-09-06

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-10-31
• Study Completion Date: 2017-09-30

Brief 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).

Conditions

Healthy

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Healthy Subjects

20 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.

Group Type: EXPERIMENTAL

FDOCT

Intervention Type: DEVICE

Measurement of retinal blood velocities

LDV

Intervention Type: DEVICE

Measurement of retinal blood velocities

DVA

Intervention Type: DEVICE

Measurement of retinal vessel diameters

LSFG

Intervention Type: DEVICE

Imaging of retinal blood flow

Interventions

FDOCT

Measurement of retinal blood velocities

Intervention Type: DEVICE

LDV

Measurement of retinal blood velocities

Intervention Type: DEVICE

DVA

Measurement of retinal vessel diameters

Intervention Type: DEVICE

LSFG

Imaging of retinal blood flow

Intervention Type: DEVICE

Other Intervention Names

Fourier Domain Color Doppler Optical Coherence Tomography; Laser Doppler Velocimetry; Dynamic Vessel Analyzer; Laser Speckle Flowgraphy

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Medical University of Vienna

OTHER

Sponsor Role: lead

Responsible Party

Gerhard Garhofer

Assoc. Prof. Dr.

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Gerhard Garhoefer, MD

Role: PRINCIPAL_INVESTIGATOR

Department of Clinical Pharmacology, Medical University of Vienna

Locations

Department of Clinical Pharmacology, Medical University of Vienna, Austria

Vienna, , Austria

Countries

Austria

References

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.

Reference Type: DERIVED

PMID: 27409462 (View on PubMed)

Other Identifiers

OPHT-250315

Identifier Type: -

Identifier Source: org_study_id