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Measurement of Total Retinal Blood Flow and Oxygen Extraction in Patients With Diabetes and Healthy Subjects

NCT03552562 · Status: RECRUITING · Phase: NA · Type: INTERVENTIONAL · Enrollment: 120

Last updated 2025-05-23

No results posted yet for this study

Summary

The prevalence of diabetes and diabetes-associated complications is still increasing. Several major long-term complications of diabetes such as cardiovascular disease, chronic renal failure, diabetic retinopathy and others relate to the damage of blood vessels. Given that the eye provides the unique possibility in the human body to directly visualize blood vessels, much interest has been directed towards studying the ocular circulation and retinal oxygen metabolism.

Although data of large epidemiological studies indicate that changes in retinal vessel caliber reflect other diabetes related factors, such as fasting glucose levels, there is still conflicting evidence on blood flow alterations in patients with diabetes. Strongly related to ocular blood flow, investigation of retinal oxygen metabolism has received a lot attention. In particular, hypoxia is assumed to be major trigger of neovascularisation in the retinal of diabetic patients The present study seeks to investigate both ocular blood flow and tissue oxygen extraction in patients with type II diabetes. For this purpose, total retinal blood flow will be assessed with bi-directional Fourier Domain Doppler Optical Coherence Tomography (FDOCT). Furthermore, retinal oxygen saturation will be measured non-invasively by a fundus camera based system. Based on data of retinal blood flow and retinal oxygen saturation, retinal oxygen. This will help to better understand ocular blood flow changes and oxygen metabolism in patients with type II diabetes.

Conditions

  • Retinal Blood Flow

Interventions

DEVICE

Fourier Domain Color Doppler Optical Coherence Tomography (FDOCT)

Fourier domain OCT is based on a local phase analysis of the backscattered signal and allows for bidirectional Doppler flow imaging.(Leitgeb et al. 2003a; Leitgeb et al. 2003b) It does not need reference arm scanning and records one full depth and Doppler profile in parallel. The system operates with an equivalent A-scan rate of 25 kHz and allows real time imaging of the color encoded Doppler information together with the tissue morphology at a rate of 2-4 tomograms (40 x 512 pixel) per second. Despite the high detection speed we achieve a system sensitivity of 86dB using a beam power of 500μW at the cornea. The fundus camera allows simultaneous view for selection of the region of interest. We observe bi-directional blood flow and pulsatility of blood velocity in retinal vessels with a Doppler detection bandwidth of 12.5 kHz and a longitudinal velocity sensitivity in tissue of 200μm/s. Diffuse luminance flicker will be applied during the measurements for 60 seconds.

Sponsors & Collaborators

  • Medical University of Vienna

    lead OTHER

Study Design

Allocation
NON_RANDOMIZED
Purpose
DIAGNOSTIC
Masking
SINGLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
99 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2018-11-21
Primary Completion
2026-03-09
Completion
2026-03-09

Countries

  • Austria

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT03552562 on ClinicalTrials.gov