Optical coherence tomography angiography analysis of macular vessel density before and after anti-VEGF therapy in eyes with diabetic retinopathy.

PURPOSE: To evaluate changes in macular vessel density following intravitreal anti-VEGF injection in patients with diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). METHODS: In this retrospective case series, optical coherence tomography angiography (OCTA) images from 55 eyes of 35 patients with either DME (46 eyes) or PDR (9 eyes) were included. Macular capillary vessel density at the level of the superficial retinal capillary plexus (SCP), deep retinal capillary plexus (DCP) and total retinal capillary plexus (TCP) before and after anti-VEGF treatment was calculated. Longitudinal changes in vessel density following serial anti-VEGF treatment were analyzed in a subset of eyes. RESULTS: Vessel density in the SCP, DCP or TCP was not found to be significantly different after one, two or three intravitreal injections (p > 0.05 for all time points). Subgroup analysis revealed no significant change in the DME and PDR subgroups (all p > 0.05). Multivariate analysis revealed no effect of type of injected anti-VEGF agent or presence of previous treatment on VD measurements (all p > 0.05). There was no correlation between the anatomic response of DME to treatment and VD measurements. CONCLUSIONS: In this study, macular vessel density remained statistically unchanged following up to three intravitreal injections of any anti-VEGF agent. This indicates that there may not be an early effect of anti-VEGF treatment on macular vessel density and its effect on macular perfusion may not be a direct change in microvascular flow.

VISUALIZATION OF CHOROIDAL NEOVASCULARIZATION USING TWO COMMERCIALLY AVAILABLE SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY DEVICES.

PURPOSE: To compare the sensitivity of detection and the measured size of choroidal neovascularization (CNV) on two commercially available spectral domain optical coherence tomography angiography (OCTA) devices, the Optovue RTVue XR Avanti with AngioVue and the Zeiss Cirrus HD-OCT with AngioPlex. METHODS: Patients with CNV lesions were imaged consecutively on both OCTA devices on the same day of their visit. 3 × 3 mm and 6 × 6 mm scans centered at the fovea were obtained. Two independent masked readers evaluated the OCTA images for CNV identification and its area measurements. RESULTS: No significant differences were observed between the 2 OCTA devices in CNV area measurements on their 3 × 3 mm and 6 × 6 mm scans. However, there was suboptimal performance of their automated segmentation algorithms as compared to manually adjusted segmentation for visualizing CNV lesions. CONCLUSION: There was no significant difference in the size of the CNV lesion as measured on either commercially available spectral domain OCTA device. Both devices were comparable in their detection of CNV lesions on manual adjustment of segmentation lines. However, their automated segmentation algorithms need improvement to allow for accurate measurement of CNV lesions for routine clinical application.

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.

Use of OCTA, FA, and Ultra-Widefield Imaging in Quantifying Retinal Ischemia: A Review.

As ischemia remains a key prognostic factor in the management of various diseases including diabetic retinopathy, an increasing amount of research has been dedicated to its quantification as a potential biomarker. Advancements in the quantification of retinal ischemia have been made with the imaging modalities of fluorescein angiography (FA), ultra-widefield imaging (UWF), and optical coherence tomography angiography (OCTA), with each imaging modality offering certain benefits over the others. FA remains the gold standard in assessing the extent of ischemia. UWF imaging has allowed for the assessment of peripheral ischemia via FA. It is, however, OCTA that offers the best visualization of retinal vasculature with its noninvasive depth-resolved imaging and therefore has the potential to become a mainstay in the assessment of retinal ischemia. The primary purpose of this article is to review the use of FA, UWF, and OCTA to quantify retinal ischemia and the various methods described in the literature by which this is achieved.

Fundus autofluorescence and spectral domain optical coherence tomography in recurrent serpiginous choroiditis: case report.

PURPOSE: To report fundus autofluorescence (FA) and spectral domain optical coherence tomography (SDOCT) findings in serpiginous choroiditis. DESIGN: Case report. METHODS: SDOCT and FA imaging of a 37-year-old woman with bilateral recurrent serpiginous choroiditis. RESULTS: Active new lesions disclosed hyperautofluorescence, in contrast to hypoautofluorescent scarred lesions. SDOCT showed increased reflectance of the choroid and deeper retinal layers, along with disruption of the photoreceptor inner and outer segment junction in both active and inactive lesions. CONCLUSION: Autofluorescence imaging and SDOCT are useful noninvasive methods for the evaluation of serpiginous choroiditis. Autofluorescence imaging allows identification of recurrences and retinal pigment epithelium involvement in the follow-up of this disease.