Assessment of Retinal Vessel Diameters and Red Blood Velocities in Patients With BRVO and Healthy Subjects

Overview

Assessment of retinal vessel calibers combined with bidirectional Fourier domain optical coherence tomography (FDOCT) for measurement of retinal blood velocities is a new and sophisticated method for assessing retinal blood flow in humans. The valid measurement of retinal blood flow is of significant importance, because it is known that major ophthalmic diseases are associated with alterations in blood flow. As such, retinal vascular occlusive diseases represent a major cause of visual impairment and blindness. The prevalence of the disease is between 0.7 and 1.6%. Compression of the retinal veins at arterio-venous (AV) crossings plays an important role in the development of branch retinal vein occlusion (BRVO). The mechanical narrowing of the vessel lumen is supposed to be the mechanism behind this fact. The present study should elucidate how BRVO influences retinal blood flow at retinal vessel crossings in comparison to healthy control subjects. Retinal blood flow at retinal bifurcations will also be assessed. In addition, a fundus image will be taken to assess retinal oxygen saturation. For the first time we use a combination of a dynamic vessel analyzer (DVA) with bidirectional Fourier domain optical coherence tomography (FDOCT) to assess retinal blood flow. Whereas the DVA provides information concerning retinal vessel caliber, FDOCT provides laser Doppler information in addition to conventional optical coherence tomography, allowing the observation of blood flow dynamics simultaneously. In the present study we hypothesize that the DVA in combination with FDOCT is a suitable new tool for the assessment of blood flow in healthy subjects and in patients with BRVO.