Diabetic Retinopathy
Conditions
Keywords
Diabetes, ocular blood flow
Brief summary
A variety of studies demonstrate that ocular blood flow is altered in diabetes and retinal perfusion abnormalities have been proposed to contribute to the pathogenesis of diabetic retinopathy. Various animal and human studies have demonstrated that retinal and optic nerve blood flow increase in response to diffuse luminance flicker. Based on studies with ERG, this effect has been attributed to augmented activity in the retinal ganglion cells and associated axons indicating a coupling mechanism between neuronal activity and retinal blood flow. Whereas a variety of studies describe the effects of flickering light on retinal and optic nerve head blood flow, the knowledge about this coupling in the diabetic retina is sparse. In view of the fact that neural activity and blood flow are strongly coupled in the human retina, one could hypothesize that neurodegenerative changes in the retina could contribute to the vascular dysregulation and in turn lead to changes of ocular perfusion. The investigators set out to investigate whether the coupling of neural activity and blood flow is impaired in patients with early stage diabetic retinopathy compared to those in healthy volunteers.
Interventions
non-invasive haemodynamic measurements of retinal vessel diameters and laser Doppler velocimetry
Sponsors
Gerhard Garhofer
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
20 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Men and women aged between 20 and 50 years * Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant * Inclusion criteria of patients are insulin dependent diabetes mellitus (IDDM) with non or mild non-proliferative retinopathy. Patients with no signs of diabetic retinopathy (level 1) or patients with one or more microaneurysms (level 2) will be included. Duration of Diabetes is between 5 and 20 years * Men and women will be included in equal parts. A pregnancy test will be performed at screening * Ametropia of less than 3 diopters and anisometropia of less than 1 diopter
Exclusion criteria
* Non insulin dependent diabetes * Maturity onset diabetes of the young (MODY diabetes) * Any sign of non diabetes induced vascular pathologies, systemic hypertension (defined as systolic blood pressure \> 150 mm Hg and diastolic blood pressure \> 90 mm Hg.) * Presence of intraocular pathology other than diabetic retinopathy * History or family history of epilepsy * Pregnancy
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Intraocular pressure | 90 minutes |
| Retinal arterial and venous diameter | 90 minutes |
| Retinal blood velocity | 90 minutes |
| Pattern ERG | measured once on the study day |
Secondary
| Measure | Time frame |
|---|---|
| Mean arterial pressure | 90 minutes |
| Blood glucose | measured once on the study day |
Countries
Austria
Outcome results
None listed