Morphological changes in intraretinal microvascular abnormalities after anti-VEGF therapy visualized on optical coherence tomography angiography

Background:To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities(IRMAs)in response to anti-vascular endothelial growth factor(anti-VEGF)treatment,documented by optical coherence tomography angiography(OCTA)in diabetic eyes.Methods:In this retrospective study,IRMAs were evaluated with multimodal imaging(fundus photography,fluorescein angiography,OCTA)in treatment-naïve diabetic eyes before and after anti-VEGF treatment for diabetic macular edema(DME)and/or proliferative diabetic retinopathy(PDR)and compared to diabetic control eyes with similar diabetic retinopathy(DR)severity that did not receive anti-VEGF therapy.The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline,then after anti-VEGF therapy in treated eyes or after observation in control eyes.Characterization of interval changes in an IRMA were based on the following parameters:branching,vessel caliber and area of adjacent capillary non-perfusion.Results:The treated group included 45 IRMA foci from 15 eyes of 11 patients,while the control group included 27 IRMA foci from 15 eyes of 14 patients.Following anti-VEGF treatment,enface OCTA demonstrated that 14 foci of IRMA(31%)demonstrated regression with normalization of appearance of the capillary bed,20 IRMAs(44%)remained unchanged,six IRMAs(13%)progressed with enlargement or development of new IRMAs and five IRMAs(11%)demonstrated complete obliteration defined as IRMA disappearance with advancing capillary drop-out.In the control group,17 IRMA(63%)remained stable,8 IRMAs(29.6%)progressed and 2 experienced total obliteration(7.4%).The difference in rank order between the two groups was statistically significant(p=0.022).Conclusions:In eyes with DR status post anti-VEGF therapy,foci of IRMAs have a variable course demonstrating one of four possible outcomes:regression,stabilit,progression or complete obliteration.In contrast,none of the untreated control diabetic eyes demonstrated regression of IRMAs,consistent with known progression of DR severity in high risk eyes.Morphologic evaluation of IRMAs with OCTA may help to monitor changes in retinal blood flow as well as the response to anti-VEGF treatment.

Choriocapillaris changes in dry age-related macular degeneration and geographic atrophy: a review

Age-related macular degeneration(AMD)is a leading cause of central vision loss worldwide.The progression of dry AMD from early to intermediate stages is primarily characterized by increasing drusen formation and adverse impact on outer retinal cells.Late stage AMD consists of either geographic atrophy(GA),the non-exudative(dry)AMD subtype,or choroidal neovascularization,the exudative(wet)AMD subtype.GA is characterized by outer retinal and choroidal atrophy,specifically the photoreceptor layer,RPE,and choriocapillaris.Much remains to be discovered regarding the pathogenesis of AMD progression and subsequent development of GA.As the functionality of all three layers is closely linked,the temporal sequence of events that end up in atrophy is important in the understanding of the pathogenic pathway of the disease.The advent of OCTA,and particularly of swept-source technology,has allowed for depth-resolved imaging of retinal vasculature and the choriocapillaris.With the use of OCTA,recent studies demonstrate that choriocapillaris flow alterations are closely associated with the development and progression of AMD.Such changes may even possibly offer predictive value in determining progression of GA.This article reviews studies demonstrating choriocapillaris changes in dry AMD and summarizes the existing literature on the potential role of the choriocapillaris as a key factor in the pathogenesis of AMD.

Morphological changes in intraretinal microvascular abnormalities after anti-VEGF therapy visualized on optical coherence tomography angiography

Background:To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities(IRMAs)in response to anti-vascular endothelial growth factor(anti-VEGF)treatment,documented by optical coherence tomography angiography(OCTA)in diabetic eyes.Methods:In this retrospective study,IRMAs were evaluated with multimodal imaging(fundus photography,fluorescein angiography,OCTA)in treatment-naive diabetic eyes before and after anti-VEGF treatment for diabetic macular edema(DME)and/or proliferative diabetic retinopathy(PDR)and compared to diabetic control eyes with similar diabetic retinopathy(DR)severity that did not receive anti-VEGF therapy.The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline,then after anti-VEGF therapy in treated eyes or after observation in control eyes.Characterization of interval changes in an IRMA was based on the following parameters:branching,vessel aliber and area of adjacent capllary non-perfusion.Results:The treated group included 45 IRMA foci from 15 eyes of 11 patients,while the control group included 27 IRMA foci from 15 eyes of 14 patients.Following anti-VEGF treatment,enface OCTA demonstrated that 14 foci of IRMA(31.1%)demonstrated regression with normalization of appearance of the capillary bed,20 IRMAs(44.4%)remained unchanged,6 IRMAs(13.3%)progressed with enlargement or development of new IRMAs and 5 IRMAs(11.1%)demonstrated complete obliteration defined as IRMA disappearance with advancing capillary drop-out.In the control group,17 IRMAs(63.0%)remained stable,8 IRMAs(29.6%)progressed and 2 experienced total obliteration(7.4%).The dfference in rank order between the two groups was statistically significant(P=0.022).Conclusions:In eyes with DR status post anti-VEGF therapy,foci of IRMAs have a variable course demonstrating one of four possible outcomes:regression,stability,progression or complete obliteration.In contrast,none of the untreated control diabetic eyes demonstrated regression of IRMAs,consistent with known progression of DR severity in high risk eyes.Morphologic evaluation of IRMAs with OCTA may help to monitor changes in retinal blood flow as wellas the response to anti-VEGF treatment.