Repeatability of measuring the vessel density in patients with retinal vein occlusion: An optical coherence tomography angiography study

Abstract

To determine the repeatability of superficial vessel density measurements using Spectral domain Ocular coherence tomography angiography(SD-OCTA) in patients diagnosed with retinal vein occlusion(RVO). Design Prospective observational study. Subjects Patients who visited our retinal clinic from August 2017 to August 2018, diagnosed with RVO were recruited for the study. Methods Two consecutive 3×3 mm pattern scans were performed using the Cirrus HD-OCT 5000 along with AngioPlex software (Carl Zeiss Meditec) in each eye by single skilled examiner. All scans were analyzed using en face OCTA images to measure vessel density (VD) automatically. For further analysis of the effect of central macular thickness(CMT), eyes were divided into two groups according to CMT of 400μm (Group 1: CMT > 400μm, Group 2: CMT < 400μm). To identify factors affecting the repeatability of VD measurements, linear regression analyses were conducted for the coefficient of variation (CV) of VD by investigating demographics and ocular variables. Main outcome measures The intraclass correlation coefficient (ICC), coefficient of variation (CV) of VD measurements.

Repeatability of Vascular Density Measurement of the Three Retinal Plexus Layers Using OCT Angiography in Pathologic Eyes (OCTA Vascular Density Repeatability of Three Plexus Layers)

“…In eyes with retinal vasculopathy, macular ischemia resulting in reduced visual acuity and reduced retinal VD, may contribute to the reduced repeatability of VD measurement. 20 Based on our study observations, we recommend using the higher image quality 3x3 mm OCTA scan in eyes with retinal vasculopathy and/or CME for more accurate and reliable VD measurement of the cDCP and cICP.…”

“…A recent study in eyes with retinal vein occlusion also showed some reduction in repeatability of VD measurement with increasing macular thickness, but this study was limited to SCP and did not evaluate the deeper plexus layers. 20 …”

“…A recent study in eyes with retinal vein occlusion also showed some reduction in repeatability of VD measurement with increasing macular thickness, but this study was limited to SCP and did not evaluate the deeper plexus layers. 20 To evaluate the effect of retinal vasculopathy on repeatability of VD measurement, we evaluated the ICC of the subset of eyes with retinal vasculopathy without CME. Repeatability of VD measurement for SCP and DCP was high, but the repeatability of VD measurement for the cDCP and cICP was reduced using the 6x6 mm OCTA scan but not as severely reduced as that noted among eyes with CME.…”

“…11,16 Others showed repeatability of the VD of the SCP can be affected by signal strength, visual acuity, average VD, and macular thickness in normal eyes and eyes with retinal pathology. [17][18][19][20][21] Repeatability of the VD of the deeper retinal capillary layers was not evaluated in these studies due to concerns about projection artifacts. A few studies that did evaluate repeatability of the VD of the DCP were limited to normal eyes and showed variable findings depending on the machine used.…”

“…12 We selected this OCTA instrument since the software for VD measurement is now commercially available and was used previously to measure VD of the cDCP and cICP in eyes with diabetic retinopathy. 5 Since fundus pathology can affect VD repeatability of the SCP, [17][18][19][20] we enrolled eyes with retinal vasculopathy, macular edema, and optic nerve pathology as well as contralateral normal eyes. We tested the hypothesis that repeatability of VD measurement of all three plexus layers is high and unaffected by retinal vasculopathy or macular edema.…”