Retinal blood flow reduction after panretinal photocoagulation in Type 2 diabetes mellitus: Doppler optical coherence tomography flowmeter pilot study

Abstract

To use a Doppler optical coherence tomography (DOCT) flowmeter to investigate segmental retinal blood flow (RBF) and sum of the segmental RBFs (SRBF) changes after panretinal photocoagulation (PRP) was used to treat type 2 diabetes mellitus with severe diabetic retinopathy (DR). Data from five patients with proliferative DR (PDR) (mean age 51.9 ± 10.5 years) was analyzed. The vessel diameter (D), average velocity (V), and retinal blood flow (RBF) in veins were measured using a DOCT flowmeter before and four weeks after PRP. Segmental RBF from inferotemporal (IT), superotemporal (ST), inferonasal (IN), and superonasal (SN) veins were measured, and SRBF was defined as the sum of these measurements. All data were analyzed by Wilcoxson test. After PRP, there were statistically significant decreases in the every segmental D, V, RBF (P<0.03) and SRBF (P = 0.002). The other parameters showed no statistically significant differences (P>0.05). The DOCT flowmeter has the potential to be a clinically useful tool to noninvasively evaluate the changes in retinal circulation during PRP in patients with PDR.

Blood flow rate estimation in optic disc capillaries and vessels using Doppler optical coherence tomography with 3D fast phase unwrapping

“…They relate the results from a specific diagnostic technique or even a specific type of a device to the established norms and pathology classifications. However, only a few papers exist reporting volumetric blood flow values measured with OCT techniques in a limited number of cases [15] [31][32][33][34][35]. Therefore, to answer the first question we have performed two tests, which do not require comparisons with established norms, yet show the reliability of the calculated volumetric flow rate values.…”

Deterioration of Retinal Blood Flow Parameters in Branch Retinal Vein Occlusion Measured by Doppler Optical Coherence Tomography Flowmeter

“…RBF was evaluated according to the established method ( Figure 1 ) [ 10 , 11 , 12 ]. Before the blood flow imaging, firstly, a color fundus image was captured.…”

“…The blood vessel can be treated as a straight line and the measurement of the systolic and diastolic phase was performed over approximately 2 s. Using the retinal motion tracking function, the scan location was adjusted accordingly for the scanning time. In most cases, at least one systolic and one diastolic phase pulsation curve could be seen for approximately 2 s. The Doppler shift image (phase image) was determined according to the established method by determining the phase difference between the two adjacent scans [ 10 , 11 , 12 ]. The vessel location and its center and diameter were identified by registering and adding the collected phase images using the automated software ( Figure 1 B).…”

“…We evaluated the vessel diameter, blood velocity, and RBF using a DOCT flowmeter according to the established method ( Figure 1) [10][11][12][13]. Our system was based on a commercially available SD-OCT system (3D OCT-1 Maestro; Topcon Corp., Tokyo, Japan), which operates at the 800 nm wavelength range [12].…”

“…Therefore, we excluded the cases when the Doppler angle was calculated to be more than 86 degrees. RBF was evaluated according to the established method ( Figure 1) [10][11][12]. Before the blood flow imaging, firstly, a color fundus image was captured.…”