Mid- to Late-Life Time-Averaged Cumulative Blood Pressure and Late-Life Retinal Microvasculature: The ARIC Study.

Background The associations of time-averaged cumulative blood pressure (BP) from midlife to late life with microvasculature expressed as retinal vessel diameters is not well studied. The aim of this study was to evaluate the association of cumulative systolic BP and diastolic BP (DBP) with retinal vessel calibers, focusing on race differences. Methods and Results The analysis included 1818 adults from the ARIC (Atherosclerosis Risk in Communities) study attending the fifth visit (2011-2013; age 77±5 years, 17.1% Black participants). Time-averaged cumulative BPs were calculated as the sum of averaged BPs from adjacent consecutive visits (visits 1-5) indexed to total observation time (24±1 years). Summarized estimates for central retinal arteriolar equivalent and central retinal venular equivalent at the fifth visit represent average retinal vessel diameters. The arteriole:venule ratio was calculated. We tested for effect modification by race. Results from multiple linear regression models suggested that higher time-averaged cumulative DBP (ß [95% CI] per 1-SD increase: -1.78 [-2.53, -1.02], P<0.001 and -0.005 [-0.009, -0.002], P=0.004, respectively) but not systolic BP (-0.52 [-1.30, 0.26], P=0.189 and 0.001 [-0.002, 0.005], P=0.485, respectively) was associated with smaller central retinal arteriolar equivalent and arteriole:venule ratio. The association between time-averaged cumulative DBP and arteriole:venule ratio was strongest in White participants (interaction P=0.007). The association of cumulative systolic BP and DBP with central retinal venular equivalent was strongest in Black participants (interaction P=0.015 and 0.011, respectively). Conclusions Exposure to higher BP levels, particularly DBP, from midlife to late life is associated with narrower retinal vessel diameters in late life. Furthermore, race moderated the association of cumulative BP exposure with retinal microvasculature.

Contributions of Sodium-Hydrogen Exchanger 1 and Mitogen-Activated Protein Kinases to Enhanced Retinal Venular Constriction to Endothelin-1 in Diabetes.

Diabetes elevates endothelin-1 (ET-1) in the vitreous and enhances constriction of retinal venules to this peptide. However, mechanisms contributing to ET-1-induced constriction of retinal venules are incompletely understood. We examined roles of sodium-hydrogen exchanger 1 (NHE1), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and extracellular calcium (Ca2+) in retinal venular constriction to ET-1 and the impact of diabetes on these signaling molecules. Retinal venules were isolated from control pigs and pigs with streptozocin-induced diabetes for in vitro studies. ET-1-induced vasoconstriction was abolished in the absence of extracellular Ca2+ and sensitive to c-Jun N-terminal kinase (JNK) inhibitor SP600125 but unaffected by extracellular signal-regulated kinase (ERK) inhibitor PD98059, p38 kinase inhibitor SB203580, or broad-spectrum PKC inhibitor Gö 6983. Diabetes (after 2 weeks) enhanced venular constriction to ET-1, which was insensitive to PD98059 and Gö 6983 but was prevented by NHE1 inhibitor cariporide, SB203580, and SP600125. In conclusion, extracellular Ca2+ entry and activation of JNK, independent of ERK and PKC, mediate constriction of retinal venules to ET-1. Diabetes activates p38 MAPK and NHE1, which cause enhanced venular constriction to ET-1. Treatments targeting these vascular molecules may lessen retinal complications in early diabetes.

Central retinal vascular trunk deviation in unilateral normal-tension glaucoma.

PURPOSE: To investigate whether the position of the central retinal vascular trunk (CRVT), as a surrogate of lamina cribrosa (LC) offset, was associated with the presence of glaucoma in normal-tension glaucoma (NTG) patients. METHODS: The position of the CRVT was measured as the deviation from the center of the Bruch's membrane opening (BMO), as delineated by spectral-domain optical coherence tomography imaging. The offset index was calculated as the distance of the CRVT from the BMO center relative to that of the BMO margin. The angular deviation of CRVT was measured with the horizontal nasal midline as 0° and the superior location as a positive value. The offset index and angular deviation were compared between glaucoma and fellow control eyes within individuals. RESULTS: NTG eyes had higher baseline intraocular pressure (P = 0.001), a larger ß-zone parapapillary atrophy area (P = 0.013), and a larger offset index (P<0.001). In a generalized linear mixed-effects model, larger offset index was the only risk factor of NTG diagnosis (OR = 31.625, P<0.001). A generalized estimating equation regression model revealed that the offset index was larger in the NTG eyes than in the control eyes for all ranges of axial length, while it was the smallest for the axial length of 23.4 mm (all P<0.001). CONCLUSIONS: The offset index was larger in the unilateral NTG eyes, which fact is suggestive of the potential role of LC/BMO offset as a loco-regional susceptibility factor.

Retinal Nonperfusion Relationship to Arteries or Veins Observed on Widefield Optical Coherence Tomography Angiography in Diabetic Retinopathy.

Purpose: To evaluate whether retinal capillary nonperfusion is found predominantly adjacent to arteries or veins in eyes with diabetic retinopathy (DR). Methods: Sixty-three eyes from 44 patients with proliferative DR (PDR) or non-PDR (NPDR) were included. Images (12 × 12-mm) foveal-centered optical coherence tomography (OCT) angiography (OCTA) images were taken using the Zeiss Plex Elite 9000. In 37 eyes, widefield montages with five fixation points were also obtained. A semiautomatic algorithm that detects nonperfusion in full-retina OCT slabs was developed, and the percentages of capillary nonperfusion within the total image area were calculated. Retinal arteries and veins were manually traced. Based on the shortest distance, nonperfusion pixels were labeled as either arterial-side or venous-side. Arterial-adjacent and venous-adjacent nonperfusion and the A/V ratio (arterial-adjacent nonperfusion divided by venous-adjacent nonperfusion) were quantified. Results: Twenty-two eyes with moderate NPDR, 16 eyes with severe NPDR, and 25 eyes with PDR were scanned. Total nonperfusion area in PDR (median: 8.93%) was greater than in moderate NPDR (3.49%, P < 0.01). Arterial-adjacent nonperfusion was greater than venous-adjacent nonperfusion for all stages of DR (P < 0.001). The median A/V ratios were 1.93 in moderate NPDR, 1.84 in severe NPDR, and 1.78 in PDR. The A/V ratio was negatively correlated with the total nonperfusion area (r = -0.600, P < 0.0001). The results from the widefield montages showed similar patterns. Conclusions: OCTA images with arteries and veins traced allowed us to estimate the nonperfusion distribution. In DR, smaller nonperfusion tends to be arterial-adjacent, while larger nonperfusion tends toward veins.

Impact of Baseline Retinal Nonperfusion and Macular Retinal Capillary Nonperfusion on Outcomes in the COPERNICUS and GALILEO Studies.

PURPOSE: To evaluate the impact of baseline retinal capillary nonperfusion (RNP) and macular retinal capillary nonperfusion (MNP) status on outcomes at week 24 (W24). DESIGN: Post hoc analyses of 2 phase 3, randomized, double-masked, multicenter, sham-controlled studies. PARTICIPANTS: Three hundred sixty-six patients with macular edema secondary to central retinal vein occlusion randomized in COPERNICUS and GALILEO. METHODS: We randomized patients 3:2 to receive intravitreal aflibercept 2 mg every 4 weeks or sham injections until W24. RNP and MNP were assessed by a masked independent reading center. MAIN OUTCOME MEASURES: Proportion of patients with 10 disc areas (DA) or more of RNP and any degree of MNP at W24, relative risks of 10 DA or more of RNP or any degree of MNP at W24 developing, change from baseline in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) by baseline RNP and MNP status, and relationship between baseline RNP and MNP status. RESULTS: At baseline, 24.6% of patients showed 10 DA or more of RNP and 72.6% showed MNP, regardless of baseline RNP status. At W24, the pooled proportions of patients in the intravitreal aflibercept and sham groups with 10 DA or more of RNP were 11.6% and 29.0%, respectively (P = 0.0001); the respective proportions with any degree of MNP were 61.2% and 79.5% (P = 0.0008). Relative risks and 95% confidence intervals for intravitreal aflibercept versus sham were 0.4 (0.25-0.62) for 10 DA or more of RNP and 0.8 (0.68-0.90) for MNP, indicating a lower risk for these outcomes with intravitreal aflibercept than with sham. Mean BCVA change was greater in intravitreal aflibercept- versus sham-treated eyes, with less than 10 DA and 10 DA or more of RNP at baseline (+17.5 vs. +0.8 letters and +18.3 vs. -4.1 letters, respectively) and with and without baseline MNP (+15.7 vs. +0.3 letters and +17.1 vs. +0.4 letters, respectively). Agreement between baseline RNP and MNP status was low (κ = 0.12). The proportions of patients with 1 or more ocular serious adverse event in the intravitreal aflibercept- and sham-treated groups, respectively, were 3.2% and 11.3%. CONCLUSIONS: At W24, visual and anatomic improvements, including perfusion status, were greater in eyes treated with intravitreal aflibercept than in eyes treated with sham, regardless of baseline RNP or MNP status.

Associations of retinal microvascular caliber with intermediate phenotypes of large arterial function and structure: A systematic review and meta-analysis.

OBJECTIVE: Intermediate phenotypes of microcirculation (retinal microvascular caliber) are associated with cardiovascular (CV) risk factors and independently predict CV events. However, the effect of microcirculation variation on the vascular system is unclear. We conducted a systematic review and meta-analysis of observational studies to quantify associations of retinal microvascular caliber (arteriolar, venular caliber, arteriole-to-venule ratio) and preclinical CV measures (large arterial function and structure). METHODS: We identified studies in MEDLINE, EMBASE, and PubMed (1946 to March 2018) studying (a) general population samples and (b) patients with cardiometabolic disease. Study-specific correlation estimates were combined into meta-analysis where possible. RESULTS: Of 1294 studies identified, 26 met inclusion criteria (general population 16, patients 10), of which five studies were included in meta-analysis. Most studied middle-aged adults cross-sectionally, with one childhood study. Large arterial function and structure were predominantly assessed by pulse wave velocity and carotid intima-media thickness, respectively. Only arteriolar caliber was consistently associated with arterial function and structure, with stronger associations observed in cardiometabolic patients. Narrower (worse) arteriolar caliber was associated with faster (poorer) pulse wave velocity (correlation coefficient (r) -0.17, 95% CI -0.25 to -0.10) and greater (poorer) intima-media thickness (r -0.05, 95%CI -0.09 to -0.02) across all adult participants. CONCLUSIONS: Retinal arteriolar, but not venular caliber, was modestly associated with large arterial function and weakly associated with large arterial structure, with stronger evidence in patients with cardiometabolic disease. This suggests that preclinical changes in large arteries and the microcirculation have some shared but mainly unique pathways to associate with cardiovascular disease.

Evaluation of retinal nonperfusion in branch retinal vein occlusion using wide-field optical coherence tomography angiography.

PURPOSE: To characterize wide-field optical coherence tomography angiography (OCTA) features of retinal nonperfusion in eyes with branch retinal vein occlusion (BRVO). METHODS: Automated scanning of five 12 × 12-mm areas of swept-source OCTA and wide-field fluorescein angiography (FA) images was performed in a consecutive case series of 27 eyes in 27 patients with BRVO in this institutional cross-sectional study. The correlation between the areas of retinal nonperfusion detected by both examinations was assessed. Panoramic images obtained in five 12 × 12-mm OCTA scans in eyes with retinal nonperfusion were binarized or skeletonized, and the associations between vascular parameters such as vascular density (VD) and vascular length (VL) with the wide-field FA characteristics were evaluated. RESULTS: The mean area of retinal nonperfusion in the OCTA images was 81.0 ± 66.8 mm2 (range, 0.0-188.8). The mean areas of retinal nonperfusion in FA and the total FA images were, respectively, 84.7 ± 72.5 mm2 (range, 0.0-221.9) and 184.1 ± 167.7 mm2 (range, 0.0-515.0). The mean VD was 27.6 ± 3.5% (range, 19.6-33.7), and the mean VL was 12.4 ± 8.5% (range, 5.4-31.3). Separate regression analyses of the areas of retinal nonperfusion in FA (p = 0.0004, R2  = 0.4627) and the total FA (p = 0.0008, R2  = 0.4214) images showed a significant association with the VL. CONCLUSIONS: OCTA images based on wide-field technologies can quantitatively evaluate retinal nonperfusion in eyes with BRVO.

RELATION BETWEEN FLUORESCEIN ANGIOGRAPHIC AND SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY FINDINGS OF BLOOD FLOW TURBULENCE AT ARTERIOVENOUS CROSSINGS IN THE RETINA.

PURPOSE: To examine retinal blood flow at arteriovenous crossings using spectral-domain optical coherence tomography (SD-OCT). METHODS: Retrospective observational case series of 11 arteriovenous crossings in 10 eyes examined by SD-OCT and fluorescein angiography on suspicion of manifest or imminent branch retinal vein occlusion. RESULTS: Fluorescein angiographic evidence of turbulence was seen at 5 of 11 arteriovenous crossings, whereas laminar angiographic flow was intact at the crossing and downstream thereof at the remaining 6 crossings. On SD-OCT, chaotic reflectivity patterns were seen at the point of crossing and downstream thereof in all 5 cases with angiographic turbulence, whereas an intravascular trilayer SD-OCT pattern consistent with laminar flow was seen throughout the examined course of the vein in the eyes with laminar angiographic flow. CONCLUSION: We examined retinal blood flow at and near arteriovenous crossings and found that SD-OCT may rival fluorescein angiography in the ability to demonstrate turbulent venous blood flow.

Association of Optical Coherence Tomography Angiography of Collaterals in Retinal Vein Occlusion With Major Venous Outflow Through the Deep Vascular Complex.

Importance: Analysis of collateral vessel formation following retinal vein occlusion may advance our understanding of the venous outflow anatomy in the macula. Objective: To determine the location of collateral vessels with optical coherence tomography (OCT) angiography imaging. Design, Setting, and Participants: Observational retrospective cohort study. Collateral vessel formation was studied with OCT angiography (OCTA) in patients with retinal vein occlusion (RVO). The study took place at 2 retinal practices (Vitreous Retina Macula Consultants of New York and Stein Eye Institute, University of California, Los Angeles), with patient records retrieved from March 2015 to August 2017. Data analysis was completed in November 2017. Exposures: Collaterals identified with fundus photography and/or fluorescein angiography were analyzed with OCTA to determine their course through the superficial vascular plexus (SVP) and the deep vascular complex (DVC). Main Outcomes and Measures: Collateral vessel pathways through the SVP and DVC were analyzed with cross-sectional and en face OCT and OCTA segmentation and color-coded volume renderings prepared from raw OCTA voxel data. Results: From 23 eyes (22 branch and 1 hemispheric retinal vein occlusion ) of 23 patients (mean [SD] age, 73 [11] years), 101 collateral vessels were identified and analyzed (mean [SD], 4.4 [2.0]; range, 2-9 collateral per eye). On OCTA, the collaterals appeared as curvilinear dilated flow signals that connected veins across the horizontal raphe or veins on opposite sides of an occluded venous segment within the same retinal hemisphere. Of the 101 collaterals analyzed, all showed greater flow signal in the DVC, and all had some portion of their course identified within the DVC. No collaterals were found exclusively in the SVP. Volume renderings for 3 cases confirmed qualitatively that retinal collateral vessels course through the retina predominantly at the level of the DVC. Conclusions and Relevance: Based on a limited number of cases, all collateral vessels associated with retinal vein occlusion were found to course through the DVC. The absence of collaterals isolated to the SVP supports a serial arrangement of the SVP and DVC, with venous drainage predominantly coursing through the DVC.

Vasoactivity of retinal veins: A potential involvement of endothelin-1 (ET-1) in the pathogenesis of retinal vein occlusion (RVO).

PURPOSE: Whilst the pathogenesis of retinal vein occlusion (RVO) is still unclear, systemic hypertension and increased level of endothelin-1 (ET-1) are known risk factors. Therefore, we studied the influence of ET-1 on the retinal veins in hypertensive rats. METHODS: We focused on the behavior of retinal veins in spontaneous hypertensive rats (SHR). To determine whether ET-1 was associated with the blood flow in eyes of SHRs, the chorioretinal blood flow in the rats was assessed using laser speckle flowgraphy (LSFG-Micro, Softcare, Fukuoka, Japan) before and after an intravenous injection of ET-1 under general anesthesia. In addition, retinas from SHRs and age-matched normotensive Wistar-Kyoto rats (WKYs) were removed, and retinal sections were immunostained for the ET-A and ET-B receptors. The protein levels of both ET-1 receptors and hypoxia-inducible factor 1 (HIF-1) in the retinal tissues were also determined by western blot analysis. RESULTS: One of the retinal veins became exceptionally constricted and was nearly occluded, and the chorioretinal blood flow significantly decreased in the retinas of SHRs following the injection of ET-1. Immunoreactivity to ET-A receptor was higher in SHR retinas than in WKY retinas. The protein levels of ET-A receptor and HIF-1 were also significantly higher in SHR retinas than in WKY retinas. CONCLUSIONS: An increase of ET-1 in circulating blood leads to the local constriction of retinal veins and this effect is accentuated in hypertensive rats by an upregulation of ET-A receptor. It is plausible that such a constriction of retinal veins increases retinal venous pressure, and may even contribute to the pathogenesis of RVO.

Retinal microcirculation imaging in sickle cell disease patients.

OBJECTIVES: To explore the feasibility of a new quantitative method for microvascular function: non-invasive retinal function imaging (RFI). in sickle cell disease (SCD) patients and healthy controls and have it benchmarked against Laser Speckle Contrast Imaging (LSCI) measurements. METHODS: The variability of Microvascular measurements was assessed in 8 SCD patients and 8 healthy matched controls. Measurements were conducted twice on two different study days. RFI was performed for assessment of arterial and venous retinal blood flow. LSCI measurements included post occlusive reactive hyperemia and IBH challenges. Measured variables included basal flow, flow upon occlusion-reperfusion and flow during an IBH. RESULTS: RFI arterial flow and venous flow and LSCI basal flow and peak flow showed excellent intra subject repeatability between days (CVC of 8.5% 9.5%, 7.6% and 7.7% respectively) and between measurements on one day (CVC of 7.0%, 7.7%, 7.6% and 4.7% respectively). RFI arterial flow (p<0.002), and RFI venous flow (p=0.007) differed significantly between SCD patients and controls in as did LSCI basal flow, maximal flow and delta flow during IBH (p<0.0001). CONCLUSIONS: RFI showed low variability for all readout measures, comparable with most microvascular measures from LSCI. The discriminating power of the RFI between SCD patients and controls demonstrate the feasibility of this device for quantitative assessment of the microcirculation in clinical research.

Normalization of Congenital Venous Stasis Retinopathy Following Sclerotherapy of a Macrocystic Lymphatic Malformation.

The authors describe, for the first time to their knowledge, a case of a congenital macrocystic lymphatic malformation of the orbit with associated venous stasis retinopathy that acutely normalized after drainage and sclerotherapy of the lesion. Prenatal ultrasound revealed prominence of the left orbital soft tissue, and at birth, the patient was noted to have unilateral proptosis, tortuous retinal vessels, and intraretinal hemorrhages in all 4 quadrants in the left eye. MRI demonstrated a primarily intraconal, multiloculated, T2-hyperintense mass consistent with a lymphatic malformation. Ultrasound-guided cyst aspiration and sclerotherapy was performed, with subsequent improvement of the proptosis and resolution of the vessel tortuosity and intraretinal hemorrhages. Although venous stasis retinopathy is usually related to central retinal vein occlusion or carotid artery occlusive disease, any entity that increases orbital venous resistance can generate retinal venous dilation and intraretinal hemorrhages, including an orbital lymphatic malformation.

ARTERIAL OXYGEN SATURATION IN NEOVASCULARIZATIONS IN PROLIFERATIVE DIABETIC RETINOPATHY.

PURPOSE: Retinal neovascularizations in proliferative diabetic retinopathy have been proposed to develop from larger retinal venules. However, angiographic evidence suggests that the new vessels may originate from both arterioles and venules, and the vitreous oxygen tension near retinal neovascularizations is similar to that of retinal arterioles. An assessment of the oxygen saturation in neovascularizations may help characterizing the vascular origin of these vessels in proliferative diabetic retinopathy. METHODS: Dual wavelength oximetry was used to study the oxygen saturation in arterioles, venules, and retinal neovascularizations in 40 eyes from 40 patients with proliferative diabetic retinopathy. RESULTS: The oxygen saturation was significantly lower in retinal venules than in arterioles and neovascularizations (P < 0.0001), and after a correction for the influence of vessel diameter, there was no significant difference between the oxygen saturation in retinal arterioles and neovascularizations (P = 0.71). Age at onset and duration of diabetes mellitus contributed significantly to the variation in oxygen saturation of the venules, whereas none of the clinical background parameters contributed to the variation in oxygen saturation in arterioles and neovascularizations. CONCLUSION: The oxygen saturation in retinal neovascularizations in proliferative diabetic retinopathy is similar to that of the arterioles. Neovascularizations may act as shunts to bypass areas of capillary occlusion.

Oxygen venular saturation correlates with a functional loss in primary open-angle glaucoma and normal-tension glaucoma patients.

PURPOSE: To investigate whether there are differences in retinal oxygen saturation in upper and lower visual field hemispheres in primary open-angle glaucoma (POAG) and in normal-tension glaucoma (NTG). METHODS: This study enrolled POAG and NTG patients exhibiting differences between the upper and lower total deviation (TD) that were either more than 10 or <5 dB. Retinal oxygen saturation measurements in these patients with glaucoma were performed by a non-invasive spectrophotometric retinal oximeter. The Student's t-test was used for statistical analysis. RESULTS: Evaluations of the worse and better hemifields in the patients with POAG who exhibited differences in the upper and lower hemifield TD that was <5 dB (n = 25) showed that there were no statistically significant differences for the retinal venous saturation of oxygen (SaO2 ). However, there was a higher mean SaO2 in the worse (57.0 ± 7.5%) versus the better (54.3 ± 7.0%) hemifield in the patients with NTG (n = 22; p = 0.007). Evaluations of the patients with more than a 10-dB difference in the upper and lower hemifield TD showed statistically significant differences for the retinal venous SaO2 in the venous vessels between the POAG (n = 19) and the NTG (n = 26) patients. CONCLUSION: Although there was no significant difference in retinal SaO2 in the venules between the better and worse hemifield when the difference between the better and worse hemifield in the patients with POAG was <5 dB, there was a higher SaO2 in the venous vessels in the worse hemifield in the patients with NTG.

Spontaneous Retinal Venous Pulsation in Unilateral Primary Open-angle Glaucoma With Low Intraocular Pressure.

PURPOSE: The aim of this study was to investigate the presence of spontaneous retinal venous pulsation (SVP) in patients with unilateral primary open-angle glaucoma (POAG) and low intraocular pressure (IOP). MATERIALS AND METHODS: The SVP of 93 POAG patients with unilateral glaucoma and untreated IOP of ≤21 mm Hg was assessed using the movie tool of a confocal scanning laser ophthalmoscope (Spectralis HRA; Heidelberg Engineering). The frequency of SVP was compared between the glaucomatous and fellow eyes. Intereye differences in the frequency of SVP were assessed using McNemar test. A linear mixed-effect model was used to determine the factors associated with glaucomatous eyes, taking into account clustering of eyes within subjects. RESULTS: Forty-five patients had SVP in both eyes and 15 had SVP in neither eye. Of the remaining 33 patients who showed SVP only in 1 eye, 31 had SVP only in the fellow eye, and 2 had SVP only in the glaucomatous eye. The SVP was significantly less prevalent in glaucomatous eyes (50.5%) than in fellow control eyes (81.7%) (P<0.001). In the linear mixed-effect model, the presence of SVP (P<0.001) and higher untreated IOP (P=0.001) were the significant predictors for glaucoma. CONCLUSIONS: SVP was less frequently found in glaucomatous eyes than healthy fellow eyes in unilateral POAG patients with low IOP.

Angiografía mediante tomografía de coherencia óptica en patología macular vascular / Optical coherence tomography angiography in macular vascular pathology

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Morphologic and Functional Retinal Vessel Changes in Branch Retinal Vein Occlusion: An Optical Coherence Tomography Angiography Study.

PURPOSE: The present study aimed to investigate the morphology of the retinal vasculature in eyes with branch retinal vein occlusion (BRVO) using optical coherence tomography (OCT) angiography. DESIGN: Observational case series. METHODS: Fluorescein angiography (FA) and OCT angiography were used to examine macular area and the retinal vasculature at the affected arteriovenous (AV) crossing in 46 patients with BRVO. RESULTS: FA revealed that the affected AV crossing pattern involved arterial overcrossing in 23 eyes (50.0%) and venous overcrossing in 11 eyes (23.9%). However, FA failed to detect the crossing pattern in 10 eyes (21.7%). OCT angiography was significantly more effective for identification of the AV crossing pattern than FA (44 eyes; 95.7%; P = .013). The number of eyes with venous overcrossing detected via OCT angiography (20 eyes, 43.5%) was also higher than that detected via FA (P = .047). OCT angiography revealed that venous narrowing (25.5 ± 21.1 µm) was significantly greater in instances of venous overcrossing than in those of arterial overcrossing (46.4 ± 23.7 µm, P = .005). Macular nonperfusion areas (NPAs) were larger in eyes with venous overcrossing than in those with arterial overcrossing (P = .011 for superficial plexus, P = .049 for deep plexus). The peripheral NPA was significantly larger in eyes with venous overcrossing (65.1 ± 35.3 disc area [DA]) than in those with arterial overcrossing (17.2 ± 24.1 DA; P < .001). CONCLUSIONS: Our findings suggest that BRVO characterized by venous overcrossing may be more prevalent than previously reported, and that there is a significant association between NPA size and AV crossing pattern.