Longitudinal analysis of quantitative biomarkers using projection-resolved OCT angiography in retinal vein occlusion

Background:To evaluate a fully automated vascular density(VD),skeletal density(SD)and fractal dimension(FD)method for the longitudinal analysis of retinal vein occlusion(RVO)eyes using projection-resolved optical coherence tomography angiography(OCTA)images and to evaluate the association between these quantitative variables and the visual prognosis in RVO eyes.Methods:Retrospective longitudinal observational case series.Patients presenting with RVO to Creteil University Eye Clinic between October 2014 and December 2018 and healthy controls were retrospectively evaluated.Group 1 consisted of central RVO(CRVO)eyes,group 2 consisted of eyes with branch RVO(BRVO)and group 3 of healthy control eyes.OCTA acquisitions(AngioVue RTVue XR Avanti,Optovue,Inc.,Freemont,CA)were performed at baseline and last follow up visit.VD,SD,and FD analysis were computed on OCTA superficial and deep vascular complex(SVC,DVC)images at baseline and final follow up using an automated algorithm.Logistic regression was performed to find if and which variable(VD,SD,FD)was predictive for the visual outcome.Results:Forty-one eyes,of which 21 consecutive eyes of 20 RVO patients(13 CRVO in group 1,8 BRVO in group 2),and 20 eyes of 20 healthy controls were included.At the level of SVC,VD and FD were significantly lower in RVO eyes compared to controls(P<0.0001 and P=0.0008 respectively).Best-corrected visual acuity(BCVA)at last follow-up visit was associated with baseline VD(P=0.013),FD(P=0.016),and SD(P=0.01)at the level of the SVC,as well as with baseline FD at the DVC level(P=0.046).Conclusions:Baseline VD,SD,and FD are associated with the visual outcome in RVO eyes.These parameters seem valuable biomarkers and may help improve the evaluation and management of RVO patients.