Abstract
Purpose: :
To investigate retinal blood flow changes in retinal diseases and optic neuropathies.
Methods: :
A Fourier-domain Doppler optical coherence tomography (FD-DOCT) system with an axial resolution of 4.6 µm was used. Flow in branch retinal veins was measured by scanning concentric circles of 3.8 and 4.0 mm diameters around the optic nerve head at a speed of 4.2 circles per second. Vessel orientation was determined from the 2 cross-sections. Volumetric flow was calculated from the cross-sectional velocity profiles. Retinal blood flow was measured in prospectively recruited patients and compared with a normal reference group. One eye was scanned in each subject.
Results: :
Total retinal blood flow (TRBF) was between 40.8 and 52.9 µl/min in 10 normal subjects. The means ± standard deviation was 45.6 ± 3.8 µl/min. In the 10 perimetric glaucoma eyes, TRBF ranged from 24.3 to 43.1 µl/minute, with 9 eyes outside of the normal range. There was a high correlation ( R2 = 0.77) between visual field (VF) pattern standard deviation and TRBF. In one case of non-arteritic ischemic optic neuropathy, the flow was abnormally low in the affected superior hemisphere and normal in the unaffected hemisphere. Two diabetic patients were studied, TRBF was below normal range in the patient with proliferative diabetic retinopathy and in the low normal range in the patient with diabetes without retinopathy.
Conclusions: :
This is a first demonstration of Doppler FD-OCT measurement of total retinal blood flow in diseased eyes. Reduction in blood flow, as measured by OCT, correlated well with the location and severity of disease in a range of optic neuropathies and retinal diseases. Doppler FD-OCT may be useful in the diagnosis, staging, and management of eye diseases associated with abnormal retinal blood flow.
Keywords: retina • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • blood supply