Aim-To measure total retinal blood flow in normal human eyes using Doppler Fourier-domain optical coherence tomography (FD-OCT).Methods-10 normal people aged 35 to 69 years were measured for the right eye using Doppler FD-OCT. Double circular scans around the optic nerve heads were used. Four pairs of circular scans that transected all retinal branch vessels were completed in 2 s. Total retinal blood flow was obtained by summing the flows in the branch veins. Measurements from the eight scans were averaged. Veins with diameters >33 μm were taken into account.Results-Total retinal blood flow could be measured in eight of 10 subjects: mean (SD) = 45.6 (3.8) μl/min (range 40.8 to 52.9 μl/min). The coefficient of variation for repeated measurements was 10.5%. Measured vein diameters ranged from 33.3 to 155.4 μm. The averaged flow speed was 19.3 (2.9) mm/s, which did not correlate with vessel diameter. There was no significant difference between flows in the superior and inferior retinal hemispheres.Conclusions-Double circular scanning using Doppler FD-OCT is a rapid and reproducible method to measure total retinal blood flow. These flow values are within the range previously established by laser Doppler flowmetry.Many of the leading causes of blindness are related to abnormalities in retinal blood flow, such as diabetic retinopathy and age-related macular degeneration. 1 2 Central and branch retinal vein occlusions are also common retinal diseases that are characterised by decreased retinal blood flow. In glaucoma, poor circulation in the retina and optic nerve is thought to be a risk factor for disease progression. 3 4 A practical and accurate method for retinal blood-flow measurement may be useful in the diagnosis and management of these diseases.Optical coherence tomography (OCT) 5 provides high-resolution cross-sectional imaging and is commonly used in the diagnosis and management of retinal diseases. 6 7 In addition to obtaining morphological images, OCT can also detect the Doppler shift of reflected light, which provides information on blood flow. 8 9 For Doppler Fourier-domain optical coherence tomography (FD-OCT), 10 11 light reflected by moving blood induces a Doppler frequency shift that is proportional to the velocity component parallel to the axis of the probe beam. This MATERIALS AND METHODS Study populationThe research protocol was approved by the institutional review board of the University of Southern California (USC), in accordance with the tenets of the Declaration of Helsinki. Ten healthy human subjects (four male, six female) between the ages of 35 and 69 years (average 57.4 years) participated in the study at the USC Doheny Eye Institute. Written informed consent was obtained from each subject. The right eyes were measured. The following inclusion criteria were met for these normal subjects: (a) no history or evidence of retinal pathology or glaucoma; (b) no history of keratorefractive surgery; (c) normal Humphrey SITA 24-2 visual field: a mean deviation (MD) and pattern standard deviat...

We present human retinal blood flow investigation for diabetic patients using Doppler Fourier domain optical coherence tomography (FD-OCT). The scanning pattern consisted of two concentric circles around the optic nerve head. The blood flow in one patient with diabetes and no retinpathy and another patient with treated proliferative diabetic retinopathy were measured. The patient without retinopathy showed a total blood flow value at the lower level of the normal range. The flow distribution between superior and inferior retina was balanced. The patient with diabetic retinopathy had a flow value lower than the normal people. Our study shows that Doppler FD-OCT can be used to evaluate the total retinal blood flow in patients with retinal diseases.

Purpose-To characterize the macular anatomy of retinal dystrophy eyes using high-speed, highresolution, Fourier-domain optical coherence tomography (FD-OCT). Design-Case control study.Methods-Patients with retinal dystrophy and normal age and gender matched controls underwent FD-OCT imaging using the RTVue™ (Optovue, Inc.), which has an axial resolution of 5 microns. Vertical and horizontal eight mm scans of 1,024 lines/cross-section were obtained. Based on boundaries manually drawn on computer displays of OCT cross-sections, the thicknesses of the retina, inner retinal layer (IRL) and outer retinal layer (ORL) were averaged over both 5 and 1.5 millimeters regions centered at the fovea. The inner retina layer (IRL) was the sum of nerve fiber layer (NFL), ganglion cell layer (GCL) and inner plexiform layer (IPL) thicknesses. Total retinal thickness (RT) was measured between the inner edges of the NFL and the retinal pigment epithelium. Outer retinal layer (ORL) thickness was calculated by subtracting IRL thickness from RT.Results-14 patients (7 retinal dystrophy patients and seven normal controls) underwent high resolution OCT imaging. Patients ranged in age from 33 to 84 years old. Retinal dystrophy diagnoses included retinitis pigmentosa (3), cone-rod degeneration (2), and Stargardt disease (2). The following thickness values reported are mean ± standard deviation. Mean foveal RT (foveal RT) averaged over a 1.5 mm area was 271.3+/-23.3μ for normal patients and 159.2+/-48.0 μ for dystrophy (p<0.001) patients. Mean macular RT (macular RT), averaged over the central 5-mm area, was 292.8+/-8.1 μ for normal patients and 199.1+/-32.7μ for dystrophy patients (p<0.001). Mean macular IRL was 109.9 ± 6.4 for normals and 98.0 +/-20.6μ for dystrophy patients (p=0.02); mean macular ORL was 182.9+/-4.7 μ for normals and 101.1+/-18.8μ for dystrophy patients (p<0.001).Conclusion-Eyes with retinal dystrophy had a small (11%) decrease in macular IRL and severe (45 %) decrease in macular ORL compared to normals. The higher resolution and definition of the FD-OCT technology facilitated measurements of the thickness of retinal sublayers.