Widefield Swept-source Optical Coherence Tomography Angiography Research Articles

Decreased choriocapillaris vessel density in the ipsilateral eye after carotid artery revascularization detected by widefield SS-OCTA.

ObjectiveTo investigate the short-term blood flow changes and image features of the retina and choroid in patients undergo carotid artery revascularization (CAR) for severe carotid artery stenosis (SCAS) using widefield swept-source optical coherence tomography angiography (SS-OCTA). DesignProspective study. ParticipantsThis prospective study included 112 eyes (56 eyes of the ipsilateral side and 56 eyes of the contralateral side) of 56 participants with severe carotid artery stenosis. MethodsParticipants were examined using widefield SS-OCTA covering an area of 16*16mm centered on the fovea before and after carotid artery revascularization. Retinal parameters including central macular thickness (CMT), vessel density of the retinal superficial vascular complex (VDRSVC), vessel density of the retinal deep vascular complex (VDRDVC), and vessel density of the retina (VDR) and choroidal parameters including central choroidal thickness (CCT), vessel density of the choriocapillaris (VDCC), vessel density of the medium and large choroidal vessels (VDMLC), choroidal vessel volume ratio (CVV/a), and three-dimensional choroidal vascularity index (3D-CVI) were measured. Besides, preoperative and postoperative OCTA images were screened and compared. Main Outcome MeasuresRetinal and choroidal parameters obtained from SS-OCTA. ResultsIn the ipsilateral eye (56 eyes), increase of VDRSVC, VDR, CVV/a, CCT, and 3D-CVI and decrease of VDCC was found after CAR. 13 patients were identified with postoperative ipsilateral choriocapillaris flow voids (PICCFVs) with OCTA images, and presence of PICCFVs was associated with greater postoperative VDCC decrease. In the contralateral eye (56 eyes), we found increase of VDRSVC, VDRDVC, VDR, while no difference of choroidal parameters after CAR and no findings of PICCFVs. ConclusionsFindings of this study suggest that ocular microvascular perfusion is improved after CAR in the ipsilateral eye and the contralateral eye within a wide field of the fundus. The VDCC is decreased in the ipsilateral eye, which may indicate infarctions of choriocapillaris or ischemia-reperfusion injury of the choriocapillaris after CAR.

Vascular Changes and Irreversible Complications in 120° Fundus Using Widefield SS-OCTA in Vogt-Koyanagi-Harada Disease.

To characterize the changes of fundus corresponding to 120° field of view in chronic Vogt-Koyanagi-Harada (VKH) disease in the quiescent phase, and explore the associations with irreversible complications in the fundus utilizing widefield swept source optical coherence tomography angiography (SS-OCTA). Prospective cross-sectional study. Sixty-nine chronic VKH patients (115 eyes) and 55 healthy controls (110 eyes) were included and underwent widefield SS-OCTA. Univariate analyses of variations in retinal and choroidal vessel density (VD), choroidal volume, and choroidal vascularity index (CVI) in VKH patients with different disease durations and the controls were conducted. Logistic regression analysis was employed to identify the associations with irreversible complications including choroidal neovascularization, vasoproliferative tumour of the retina, and chorioretinal atrophy. The Welch's analysis of variance showed lower VD of superficial retina, deep retina, choriocapillaris, and large-sized and medium-sized vessels of the choroid (LMVC), and choroidal volume and CVI in the patients with disease duration > 24 months compared to those with disease duration ≤ 24 months (all P≤0.011). The regression analysis revealed the disease duration (P=0.008; OR=1.02, 95%CI=1.005-1.035) and VD of LMVC (P=0.001; OR=0.707, 95%CI=0.575-0.87) were significantly correlated with the irreversible complications. Chronic VKH patients in the quiescent phase with disease duration > 24 months exhibit more severe decreased VD in each layer of the retina and choroid, reduced choroidal volume and sparse choroidal vascularity compared to those with disease duration ≤ 24 months. Prolonged duration and decreased VD of LMVC were associated with irreversible complications in the fundus.

Wide-field swept-source optical coherence tomography angiography (SS-OCTA) in the assessment of retinal vessel density and thickness in 4-to 16-year-old myopic children

PurposeTo analyze the characteristics of macular retinal vessel density and thickness in children with myopia. MethodsA cross-sectional study was conducted. A total of 228 children aged 4–16 years who visited the Ineye Hospital of Chengdu University of Traditional Chinese Medicine from September 2022 to November 2023 were included. Those with −0.5D < spherical equivalent (SE) < +2.0D were included in the non-myopia group (150 eyes), those with −3.0D < SE ≤ −0.5D were included in the low myopia group (246 eyes), and those with SE ≤ −3.0D were included in the moderate-to-high myopia group (60 eyes). All subjects underwent cycloplegic refraction, IOLmaster500, and Wide-field SS-OCTA (to exclude some peripheral retinal degeneration). Multiple linear regression analysis was used to analyze the correlation between macular ETDRS subfield of full retinal thickness (FRT), outer, inner retinal thickness (ORT, IRT), retinal vessel density (VD), deep and superficial retinal vessel density (DVD, SVD), and SE, axial length (AL). ResultsThere were statistically significant differences (P < 0.05) in FRT in the central fovea (1 mm diameter)and perifovea (Diameter 3 to 6 mm) among the non-myopia group, low myopia group, and moderate-to-high myopia group. The three groups also showed statistically significant differences (P < 0.05) in VD in the central fovea and parafovea with a diameter of 1 to 3 mm (except the lower part). In multiple linear regression analysis adjusted for gender and age, SE and AL were found to be correlated with FRT in all ETDRS regions (except the central fovea) (P < 0.01), and SE and AL were correlated with IRT in the central fovea and perifovea, respectively (β range −2.302 to 1.652; P < 0.05). SE and AL were also correlated with ORT in the parafovea and perifovea, respectively (β range −4.371 to −2.344; P < 0.05). AL was negatively correlated with VD in the central fovea and parafovea (except the inferior region) (P < 0.05), as well as with DVD in all ETDRS regions (β range −1.314 to −1.031; P < 0.05). AL was only negatively correlated with SVD in the parafoveal nasal region (β = −0.633, P < 0.05). Additionally, the correlation between AL and DVD, ORT was higher than that with SVD, IRT. ConclusionThe more severe the myopia, the longer the AL, the thinner the FRT in the perifovea, and the lower the VD in both the fovea and parafovea in children. In addition, DVD and ORT were more significantly correlated with AL, suggesting that they may be more closely related to the growth of AL.

Acute spontaneous vortex vein occlusion: clinical features, multimodal imaging and natural course

AimsTo describe the clinical features, multimodal imaging, treatments and natural course of acute spontaneous vortex vein occlusion.MethodsClinical data were collected on nine patients with acute vortex vein occlusion. The symptoms...

Analysis of retinal and choroidal characteristics in patients with early diabetic retinopathy using WSS-OCTA.

Diabetic retinopathy (DR) is one of the most common and destructive microvascular complications of DM, and has become a major cause of irreversible visual impairment. The purpose of this study was to evaluate the changes in fundus microcirculation in non-diabetic retinopathy (NDR) and mild non-proliferative diabetic retinopathy (NPDR) in patients with type 2 diabetic mellitus (T2DM) using widefield swept-source optical coherence tomography angiography (WSSOCTA), and to investigate the correlation with laboratory indices of T2DM. Eighty nine, 58 and 28 eyes were included in the NDR, NPDR and Control groups, respectively, were enrolled in this study. The 12mm×12mm fundus images obtained by WSS-OCTA were divided into 9 regions (supratemporal, ST; temporal, T; inferotemporal, IT; superior, S; central macular area, C; inferior, I; supranasal, SN; nasal, N; inferonasal, IN) to evaluate changes in vessel density (VD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris, and mid-large choroidal vessel (MLCV), as well as changes in inner retinal thickness (IRT), outer retinal thickness (ORT), and choroidal thickness (CT). Results: Compared with control group, MLCV VD (I, N, IN) was significantly decreased in NDR group, SCP VD (IT, C, I) and DCP VD (T, IT, I) were significantly decreased in NPDR group. In NPDR group, DCP VD (IT) was significantly decreased compared with that in NDR group. Compared with control group, CT (ST, T, IT, S, SN, IN) was significantly declined in NDR group, and IRT (ST, IT) and ORT (ST, N) were significantly increased in NPDR group. In NPDR group, IRT (ST) and ORT (T, S) were significantly increased compared with NDR group. Correlation analysis showed that age, body mass index, fasting blood glucose, fasting insulin, fasting C-peptide, and estimated glomerular filtration rate in T2DM patients were statistically correlated with retinal and choroidal thickness/VD. Structural and blood flow changes in the choroid occur before the onset of DR and precede changes in the retinal microcirculation, and MLCV thickness/VD is a more sensitive imaging biomarker for the clinical detection of DR. WSS-OCTA enables large-scale non-invasive visual screening and follow-up of the retinal and choroidal vasculature in DR patients, providing a new strategy for the prevention and monitoring of DR in patients with T2DM.

Classification of Vogt-Koyanagi-Harada disease using feature selection and classification based on wide-field swept-source optical coherence tomography angiography.

Background: Vogt-Koyanagi-Harada (VKH) disease is a common and easily blinded uveitis entity, with choroid being the main involved site. Classification of VKH disease and its different stages is crucial because they differ in clinical manifestations and therapeutic interventions. Wide-field swept-source optical coherence tomography angiography (WSS-OCTA) provides the advantages of non-invasiveness, large-field-of-view, high resolution, and ease of measuring and calculating choroid, offering the potential feasibility of simplified VKH classification assessment based on WSS-OCTA. Methods: 15 healthy controls (HC), 13 acute-phase and 17 convalescent-phase VKH patients were included, undertaken WSS-OCTA examination with a scanning field of 15 × 9mm2. 20 WSS-OCTA parameters were then extracted from WSS-OCTA images. To classify HC and VKH patients in acute and convalescent phases, two 2-class VKH datasets (HC and VKH) and two 3-class VKH datasets (HC, acute-phase VKH, and convalescent-phase VKH) were established by the WSS-OCTA parameters alone or in combination with best-corrected visual acuity (logMAR BCVA) and intraocular pressure (IOP), respectively. A new feature selection and classification method that combines an equilibrium optimizer and a support vector machine (called SVM-EO) was adopted to select classification-sensitive parameters among the massive datasets and to achieve outstanding classification performance. The interpretability of the VKH classification models was demonstrated based on SHapley Additive exPlanations (SHAP). Results: Based on pure WSS-OCTA parameters, we achieved classification accuracies of 91.61% ± 12.17% and 86.69% ± 8.30% for 2- and 3-class VKH classification tasks. By combining the WSS-OCTA parameters and logMAR BCVA, we achieved better classification performance of 98.82% ± 2.63% and 96.16% ± 5.88%, respectively. Through SHAP analysis, we found that logMAR BCVA and vascular perfusion density (VPD) calculated from the whole field of view region in the choriocapillaris (whole FOV CC-VPD) were the most important features for VKH classification in our models. Conclusion: We achieved excellent VKH classification performance based on a non-invasive WSS-OCTA examination, which provides the possibility for future clinical VKH classification with high sensitivity and specificity.

Analysis of Vascular Changes of Fundus in Behcet's Uveitis by Widefield Swept-source Optical Coherence Tomography Angiography and Fundus Fluorescein Angiography.

To investigate vascular changes of fundus in quiescent Behçet's uveitis(BU) based on widefield swept-source optical coherence tomography angiography(SS-OCTA) and fluorescein angiography (FA). This case-control study included 33 quiescent BU patients(57eyes)and 35 healthy people(60 eyes) as the control. All participants underwent the widefield SS-OCTA, and BU patients additionally underwent the FA. The quantitative analysis of the widefield SS-OCTA assessed the vessel density(VD) of 9 anatomic locations in the fundus. Vascular leakage and retinal nonperfusion on FA were assessed in BU patients. Compared with the control group using Mann-Whitney U test, BU patients had enlargement of foveal avascular zone (FAZ) (P=0.005, P=0.04, respectively) and decreased VD within a 300μm width around the FAZ(FAZ300μm) (P=0.001, P<0.0001, respectively) both in the superficial and deep retina. Larger FAZ size and lower FAZ300μm were correlated with higher logarithm of the minimum angle of resolution best-corrected visual acuity in BU (P≤0.003, P<0.0001, respectively). VD of choriocapillaris(CC), as the most widely involved of all layers of the retina and choroid, was lower in 6 locations(P≤ 0.03∼0.0001) in the peripheral fundus of BU compared to the controls. Vascular leakage and retinal nonperfusion in the peripheral fundus was observed in 54.4% and 66.7% of the patients on FA. Fovea and peripheral fundus were prone to the damage of ischemia as evidenced by significantly decreased VD of capillaries. Combination of SS-OCTA with FA could accurately evaluate the changes in the retinal and choroidal vasculature in BU.

Feasibility and Clinical Utility of Wide-Field Optical Coherence Tomography Angiography Compared to Ultrawide-Field Fluorescein Angiography in Patients with Diabetic Retinopathy

To test the diagnostic performance of a novel wide-field swept-source optical coherence tomography angiography (WF-OCTA) device in detecting retinal non-perfusion (NP) and neovascularization (NV) in eyes with diabetic retinopathy (DR) and to compare this with the standard-of-care imaging method, ultrawide-field fluorescein angiography (UWFFA). Prospective, observational, cross-sectional single-center study evaluating patients with DR imaged with WF-OCTA (Xephilio OCT-S1; Canon Inc., Tokyo, Japan) and UWFFA (Optos California; Optos plc, Dunfermline, United Kingdom). WF-OCTA images of the superficial capillary plexus (SCP) consisted of single capture 23 × 20 mm scans centered on the fovea. In UWFFA and WF-OCTA, qualitative and quantitative measurements were assessed to analyze retinal NP and NV. Vessel density (VD) in WF-OCTA and ischemic index (ISI) in UWFFA were calculated. Qualitatively, the presence of NV and NP was assessed in both WF-OCTA (posterior pole/midperipheral retina) and UWFFA (posterior pole/midperipheral retina/far peripheral retina). Ten consecutive patients with variable DR severity stages (17 eyes) were evaluated. Two eyes had to be excluded due to low quality of the WF-OCTA images. Therefore, 15 eyes were included for final analysis. Mean age was 57 years (± SD: 15.2) and the male : female ratio was 4 : 6. UWFFA identified retinal NP in 11 eyes (73%). Posterior pole NP was present in eight eyes, midperiphery NP was present in eight eyes, and far periphery NP was present in seven eyes. Retinal NV was detected in four eyes using UWFFA (two eyes with only midperiphery NV). WF-OCTA detected retinal NP in 11 eyes (9 cases with both posterior pole and midperiphery NP). NV was detected in three eyes (two with posterior pole and midperipheral NV, four with only midperipheral NV). Mean VD evaluated using WF-OCTA of the SCP was 0.40 (± SD: 0.1), and mean ISI in UWFFA was 0.09 (± SD: 1.3). Spearman's test did not show a significant correlation between the ISI in UWFFA and VD in WF-OCTA (p = 0.803). Noninvasive WF-OCTA has great potential for the management of patients with DR. This new imaging modality might be useful in daily clinical routine in order to lower the number of invasive examinations. However, in a small percentage of patients, OCTA images cannot be reliably graded for the presence of NP and NV. In these cases, conventional FA needs to be performed.

SUDDEN MONOCULAR VISION LOSS AFTER SNEEZING AS CAPTURED ON WIDEFIELD SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY-ANGIOGRAPHY.

We report an unusual case of likely combined retinal artery occlusion and retinal vein occlusion after a sneeze. Widefield swept-source optical coherence tomography-angiography was used to analyze retinal changes at one-month follow-up. The patient reported visual symptoms in his left eye immediately after sneezing five times in a row. Fundus examination showed an embolus along the superior arcade. Stroke workup revealed moderate carotid artery stenosis and a subtherapeutic INR. At one-month follow-up, fundus photography and swept-source optical coherence tomography-angiography were obtained. Fundus photography showed superior retinal whitening and arteriole attenuation, an inferior perifoveal cotton wool spot, and inferotemporal intraretinal hemorrhages. Swept-source optical coherence tomography-angiography showed loss of the deep capillary plexus superiorly and inferotemporally, most consistent with combined retinal artery and retinal vein occlusion. We report the first case of sneeze-induced combined retinal artery and retinal vein occlusion. The retina is a uniquely accessible window that provides insight into human physiology, and swept-source optical coherence tomography-angiography is a powerful tool that can give further insight into the pathophysiology of an occlusion.

Wide-field swept-source OCTA in the assessment of retinal microvasculature in early-stage diabetic retinopathy

BackgroundTo perform a quantitative analysis of retinal microvasculature in patients with early-stage diabetic retinopathy (DR) using wide-field swept-source optical coherence tomography angiography (SS-OCTA). MethodsOne hundred nineteen eyes of 119 patents (67 eyes with no DR and 52 eyes with mild-moderate nonproliferative diabetic retinopathy (NPDR)) were enrolled in this observational and cross-sectional cohort study, and an age-matched group consisting of 39 eyes of 39 non-diabetic subjects were set as the control. Each participant underwent a full ophthalmic examination, including wide-field SS-OCTA imaging. On OCTA scans (12 mm * 12 mm), the mean perfusion area (PA) and vessel density (VD) were independently measured in all 16 Early Treatment Diabetic Retinopathy Study (ETDRS) sectors. Linear regression analyses were conducted to evaluate the influences of PA.ResultsIn the central ring, there were no significant differences in the average PA and VD among the groups. In the 3 mm radius, the PA and VD of the no DR and mild-moderate NPDR were significantly decreased compared with the control group in superior and inferior quadrants. In the wide-field scans (9 and 12 mm radius), there was no significant difference in average PA and VD between the groups in each sectors (p > 0.05). Regression analysis found that the effect of VD on PA was statistically different (b = 1.311, p < 0.001).ConclusionWide-field OCTA imaging is useful for evaluating peripheral capillary perfusion in eyes with early-stage DR. Decrease in PA and VD was greater in the S3 and I3 sectors, and reductions in PA and VD were uneven in wide-filed sectors (9 and 12 mm radius).

Comparison of widefield swept-source optical coherence tomography angiography with ultra-widefield fluorescein angiography for the evaluation of lesions in retinal vein occlusion

BackgroundTo compare widefield swept-source optical coherence tomography angiography (SS-OCTA) with ultra-widefield fundus fluorescein angiography (UWF-FA) for detecting retinal vein occlusion (RVO) lesions.MethodsThirty-four eyes of 32 patients with treatment-naïve RVO were enrolled at Peking University People’s Hospital from September 2021 to March 2022. Patients were imaged with a UWF-FA (200°) and a widefield SS-OCTA using 24 × 20 mm scan single capture. Quantitative assessments of RVO lesions such as foveal avascular zone (FAZ) area and perimeter, non-perfusion areas (NPA), number of microaneurysms (MAs), capillary changes and collateral vessels were performed.ResultsThe measurement of FAZ area and perimeter were comparable between SS-OCTA and UWF-FA (0.373 (range, 0.277–0.48) mm2 vs. 0.370 (range, 0.277–0.48) mm2, P = 0.818 and 2.480 (range, 2.011–2.998) vs. 2.330 (range, 2.027–2.807) mm, P = 0.536, respectively). Intraclass correlation coefficients (ICCs) of FAZ area and perimeter between SS-OCTA and UWF-FA was high (0.999, [0.997–0.999] and 0.996 [0.991–0.996], respectively), suggesting good agreement. The mean NPA area was larger on SS-OCTA than that on UWF-FA (89.977 ± 78.805 mm2vs. 87.944 ± 77.444 mm2, P = 0.037). The ICC of NPA area was also high (0.999, [0.999–1.000]). The median of total MA count was less on SS-OCTA than on UWF-FA (7 (range, 0–19) vs.12 (range, 0–23), P < 0.001). Agreement in detecting MAs between SS-OCTA and UWF-FA was found to be good (ICC = 0.920, [0.555–0.974]).The total capillary changes and collateral vessels count were less on UWF-FA than SS-OCTA (11 ± 9 vs 6 ± 7, P < 0.001 and 4 (range, 0–6) vs 0 (range, 0–0), P < 0.001, respectively). Agreement in detecting capillary changes and collateral vessels between OCTA and UWF-FA was found to be fair (ICC = 0.733, [0.081–0.905] and 0.564, [0.039–0.805], respectively).ConclusionCompared with UWF-FA, widefield SS-OCTA was found comparable or even superior in detecting FAZ, NPA, capillary changes and collateral vessels except MAs in RVO. Widefield SS-OCTA may offer a more efficient alternative to FA for diagnosis and monitoring RVO.

Wide-field swept-source OCT angiography (23 × 20mm) for detecting retinal neovascularization in eyes with proliferative diabetic retinopathy.

Xephilio OCT-S1 can capture single-acquisition 23 × 20-mm wide-field swept-source optical coherence tomography angiography (SS-OCTA) images and high-resolution images using artificial intelligence. We aimed to evaluate the ability of wide-field SS-OCTA in the detection of retinal neovascularizations (NVs) in eyes with proliferative diabetic retinopathy (PDR). This retrospective study included 64 eyes of 36 patients (age, 57 ± 10years; 10 female, 26 male) with PDR. All patients underwent a comprehensive ophthalmological examination, including fluorescein angiography (FA), as well as fovea- and disc-centered 23 × 20-mm OCTA imaging (A-scan/B-scan, 928/807). We compared and examined the number of NV sites identified using conventional methods (merging the findings from biomicroscopy/color fundus photography, FA) and the number of NV sites identified using vitreoretinal interface and superficial retinal slabs of wide-field SS-OCTA images, including the position of NVs (nasal upper, nasal lower, temporal upper, temporal lower, or disc). We identified 168 NVs (32/40/45/35/16, in the abovementioned order) using the conventional method. Fovea-centered 23 × 20-mm OCTA images revealed 162 (96%) NVs (27/39/45/35/16). This method tended to miss nasal NV. In contrast, disc-centered 23 × 20-mm OCTA images identified nearly all NVs, detecting 166 (99%) NVs (32/40/44/34/16) in total. All NVs could be visualized using two wide-field OCTA images: fovea- and disc-centered. Wide-field (23 × 20mm) SS-OCTA-especially disc-centered-using Xephilio OCT-S1 identified nearly all NVs in eyes with PDR, with a single acquisition, thereby demonstrating its potential clinical application.

WIDEFIELD SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FINDINGS IN WAGNER SYNDROME.

To describe novel clinical and angiographic findings in Wagner syndrome. A retrospective case series of three related patients with Wagner syndrome. Patients underwent standard optical coherence tomography (OCT), B-scan ultrasonography, and fluorescein angiography in addition to wide field swept-source OCT angiography (WF SS-OCTA) (PLEX Elite 9000, Carl Zeiss Meditec Inc). Patients underwent genetic testing for a panel of hereditary vitreoretinopathies. Three related patients with Wagner syndrome were identified. All were found to have prominent vitreous strands, abnormal vitreoretinal adhesions, peripheral retinal holes, and varying degrees of myopia. A mid-peripheral tractional ridge was identified in all six eyes. All patients were positive for a known pathologic intron variant in the VCAN gene (4004-5T-A). Wide field swept-source OCT angiography (12 mm × 12 mm) was performed in two patients and demonstrated perivascular capillary loss in the superficial capillary plexus along the arcades bilaterally. One patient demonstrated associated retinal atrophy within the area of capillary loss. The capillary loss extended beyond the margin of retinal atrophy. The unusual finding of a mid-peripheral tractional ridge of the retina associated with myopia led to a genetic diagnosis of Wagner syndrome. Widefield swept-source OCT angiography demonstrated a novel feature of perivascular loss of the superficial retinal capillary plexus. This result suggests that vitreous traction may cause localized microvasculature dysfunction and subsequent retinal atrophy in Wagner syndrome. This is the first known evaluation of Wagner syndrome using OCT angiography.

Wide-field swept source optical coherence tomography angiography for peripheral polyps in peripheral exudative hemorrhagic chorioretinopathy - A case report

We depict the novel use of wide-field swept-source optical coherence tomography angiography (SSOCTA) to image and longitudinally follow peripheral polyps in peripheral exudative hemorrhagic chorioretinopathy (PEHCR). A 65-year-old man with hemorrhagic mounds in the temporal mid-periphery of his left eye underwent wide-field en face and cross-sectional SSOCTA at the baseline and 3 monthly with a total follow-up of 10 months. We were able to image the peripheral polyps and branching vascular network (BVN) on wide-field SSOCTA and document its response to treatment. The SSOCTA findings correlated well to the gold standard indocyanine green angiography (ICGA).

Role of Optical Coherence Tomography Angiography to differentiate Intraretinal microvascular abnormalities and retinal neovascularization in Diabetic Retinopathy.

ABSTRACTObjective:To assess proliferative diabetic retinopathy (PDR) and to describe the difference in angiographic representation of new vessels (NVs) and Intra retinal microvascular abnormalities (IRMA) on optical coherence tomography angiography (OCTA).Methods:A cross-sectional observational study was performed at ISRA Postgraduate Institute of Ophthalmology, Karachi, from March 2018 to September 2018. Forty-two eyes of 21 patients with history of diabetes mellitus (DM) were examined. Twenty-eight eyes with a clinical diagnosis of severe non proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR) according to early treatment diabetic retinopathy study (ETDRS) were included and evaluated using Swept source optical coherence tomography angiography (SS-OCTA). Then face wide field SS-OCTA images and co registered structural optical coherence tomography (OCT) with flow overlay were used to distinguish the features of IRMA and retinal NVs.Results:Forty-two eyes (21 patients) were examined clinically. Fourteen eyes had moderate NPDR, 15 had severe NPDR and 13 eyes had changes consistent with PDR. After clinical diagnosis, we included 28 eyes in our study based on inclusion criteria. These 28 eyes went through SS-OCTA evaluation and we observed 15 cases with PDR and 13 with severe NPDR changes. The OCTA and clinical diagnosis were similar except in 2 eyes, which is critical but not statically significant showing the importance of this noninvasive technology.Conclusions:Widefield OCTA can work as an alternative to fundus fluorescein angiography (FFA) in the diagnosis of diabetic retinopathy (DR). As it is a non-invasive and depth encoded technique so can be used frequently to monitor the retinal changes and their progression.

Microvasculature Features of Vogt-Koyanagi-Harada Disease Revealed by Widefield Swept-Source Optical Coherence Tomography Angiography.

Background: Vogt-Koyanagi-Harada (VKH) disease is a multisystem autoimmune disorder which could induce bilateral panuveitis involving the posterior pole and peripheral fundus. Optical coherence tomography angiography (OCTA) provides several advantages over traditional fluorescence angiography for revealing pathological abnormalities of the retinal vasculature. Until recently, however, the OCTA field of view (FOV) was limited to 6 × 6 mm2 scans.Purpose: This study examined retinal vasculature and choriocapillaris abnormalities across multiple regions of the retina (15 × 9 mm2 wide field, macular, peripapillary regions) among acute and convalescent VKH patients using a novel widefield swept-source OCTA (WSS-OCTA) device and assessed correlations between imaging features and best-corrected visual acuity (BCVA).Methods: Twenty eyes of 13 VHK disease patients in the acute phase, 30 eyes of 17 patients in the convalescent phase, and 30 eyes of 15 healthy controls (HCs) were included in this study. Vascular length density (VLD) in superficial and deep vascular plexuses (SVP, DVP), vascular perfusion density (VPD) in SVP, DVP, and choriocapillaris (CC), and flow voids (FV) in CC were measured across multiple retinal regions via WSS-OCTA (PLEX Elite 9000, Carl Zeiss Meditec Inc., USA) using the 15 × 9 mm2 scan pattern centered on the fovea and quantified by ImageJ.Results: Compared to HCs, acute phase VKH patients exhibited significantly reduced SVP-VLD, SVP-VPD, and CC-VPD across multiple retinal regions (all p < 0.01). Notably, the FV area was more extensive in VKH patients, especially those in the acute phase (p < 0.01). These changes were reversed in the convalescent phase. Stepwise multiple linear regression analysis demonstrated that macular DVP-VLD and macular CC-VPD were the best predictive factors for BCVA in the acute and convalescent VKH groups.Conclusion: The wider field of SS-OCAT provides more comprehensive and detailed images of the microvasculature abnormalities characterizing VKH disease. The quantifiable and layer-specific information from OCTA allows for the identification of sensitive and specific imaging markers for prognosis and treatment guidance, highlighting WSS-OCTA as a promising modality for the clinical management of VKH disease.

Widefield Swept-Source Optical Coherence Tomography Angiography Assessment of Choroidal Changes in Vogt-Koyanagi-Harada Disease.

Purpose: To investigate choroidal changes in patients with Vogt-Koyanagi-Harada disease (VKH) using widefield swept-source optical coherence tomography angiography (SS-OCTA).Methods: In this cross-sectional study, 133 eyes of 69 patients with VKH (52 eyes of 28 active VKH patients and 81 eyes of 41 inactive VKH patients) and 104 eyes of 52 age and sex matched healthy volunteers were imaged using a widefield SS-OCTA instrument. On 12 mm × 12 mm OCTA scans, mean choroidal thickness (MCT), choroidal vascularity index (CVI), choriocapillaris (CC) flow area, and mean retinal thickness (MRT) were separately calculated in the fovea (diameter of 1 mm) and in concentric rings with different radii (1–3, 3–6, 6–9, and 9–12 mm).Results: Eyes with active VKH showed significant increases in MCT, CVI, and MRT, and decreased CC flow area in all central and peripheral regions (0–1, 1–3, 3–6, 6–9, and 9–12 mm) than in the healthy eyes (p ≤ 0.01) and inactive VKH eyes (p < 0.05). Inactive VKH eyes only showed marked decrease in CC flow area in all regions compared with controls (p < 0.05). Flow voids were observed in 51 of 52 (98.1%) active VKH eyes and 50 of 81 (61.7%) inactive VKH eyes on 12 mm × 12 mm OCTA. The MCT of all regions was significantly correlated with age, disease duration, and disease activity, whereas CVI was associated with age and disease activity. The CC flow void was related to visual acuity in all regions (p < 0.05).Conclusion: Widefield SS-OCTA enables a more comprehensive evaluation of chorioretinal changes in patients with VKH disease. Structural and vascular abnormalities are observed in both the central and peripheral choroid and are closely correlated with disease activity.

WIDE-FIELD SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF DIABETIC TRACTIONAL RETINAL DETACHMENTS BEFORE AND AFTER SURGICAL REPAIR.

Wide-field (WF) swept-source (SS) optical coherence tomography angiography (SS-OCTA) was used to image diabetic tractional retinal detachments (TRDs) before and after pars plana vitrectomy. The clinical utility of SS-OCTA was assessed. Patients with diabetic TRDs were imaged prospectively with SS-OCTA. Ultrawide-field imaging was obtained when possible. Postoperative WF SS-OCTA imaging was performed. From January 2018 through December 2019, 31 eyes of 21 patients with diabetic TRDs were imaged. Wide-field SS-OCTA en-face images captured all areas of TRD and fibrovascular proliferation within the posterior pole that were visualized on ultrawide-field imaging. Optical coherence tomography angiography B-scans revealed the vascularity of preretinal membranes and identified areas of vitreoretinal traction and posterior vitreous detachment. Ten eyes underwent pars plana vitrectomy. Postoperative SS-OCTA imaging demonstrated removal of fibrovascular membranes, relief of traction, and resolution of TRDs. Retinal ischemia before and after surgical repair appeared similar. All clinically relevant features of diabetic TRDs were identified at baseline and assessed longitudinally after pars plana vitrectomy using WF SS-OCTA, which showed resolution of vitreoretinal traction and no apparent change in the status of retinal perfusion after surgery. If the media are clear and fixation is adequate, WF SS-OCTA is likely the only imaging modality needed for the diagnosis and longitudinal evaluation of diabetic TRDs.

Early Vascular and Functional Changes after Vitreoretinal Surgery: A Comparison between the Macular Hole and Epiretinal Membrane.

(1) Background: The aim of this observational comparative study was to investigate early retinal vascular and functional changes in patients undergoing vitreoretinal surgery for idiopathic epiretinal membrane (iERM) or macular hole (MH) using a widefield swept-source optical coherence tomography angiography (WSS-OCTA). (2) Methods: Forty one diseased eyes were enrolled in the study. Twenty three eyes with iERM diagnosis (ERM group) underwent 25-gauge vitrectomy with inner limiting membrane (ILM) and MER peeling, while eighteen eyes with MH (MH group) underwent 25-gauge vitrectomy with inverted flap technique. Functional and anatomical/perfusion parameters were evaluated pre- and postoperatively in all eyes by means of WSS-OCTA system, microperimetry (MP3), best corrected visual acuity assessment, central macular thickness (CMT) and MH diameter calculation. For each eye, 12 × 12 mm OCTA volume scans were acquired by a retinal specialist and a semi-automated algorithm was used for a quantitative vessel analysis of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC). In detail, perfusion density (PD) of the SCP, DCP and CC was evaluated in four circles (one central in the macular area of 5 mm diameter; three midperiphery circles (temporal, superior and inferior) of 3 mm). In addition, the vessel length density (VLD) of the SCP and DCP for the same circles was quantified. (3) Results: In the MH group, PD of the SCP significantly increased in the macular area (p = 0.018) and in the superior ring (p = 0.016); PD of the DCP significantly increased in the macular area (p = 0.015) and in the superior and inferior ring (p = 0.016) 3 months after surgery. In the ERM group, PD of the SCP and DCP significantly increased in the macular area and superior ring, respectively (p = 0.001; p = 0.032), 3 months after surgery. During follow-up there was a significant improvement in terms of functional (Best corrected visual acuity, p = 0.007 and p = 0.029; microperimetry ((MP3) 10°, p = 0.003 and p = 0.004; MP3 2°, p = 0.028 and p = 0.003 in MH group and ERM group respectively) and anatomical parameters (CMT, p = 0.049 in ERM group; hole complete closure in MH group). (4) Conclusions: After vitreoretinal surgery, early retinal vascular and functional changes can be promptly observed and quantified to monitor and potentially predict surgery outcomes. Widefield OCTA devices allow for a detailed microvasculature analysis of retina and choriocapillaris in the macular area and in the periphery, showing a different behaviour of retinal sectors in two distinct vitreoretinal disorders.

Convolutional Network With Twofold Feature Augmentation for Diabetic Retinopathy Recognition From Multi-Modal Images.

With the scenario of limited labeled dataset, this paper introduces a deep learning-based approach that leverages Diabetic Retinopathy (DR) severity recognition performance using fundus images combined with wide-field swept-source optical coherence tomography angiography (SS-OCTA). The proposed architecture comprises a backbone convolutional network associated with a Twofold Feature Augmentation mechanism, namely TFA-Net. The former includes multiple convolution blocks extracting representational features at various scales. The latter is constructed in a two-stage manner, i.e., the utilization of weight-sharing convolution kernels and the deployment of a Reverse Cross-Attention (RCA) stream. The proposed model achieves a Quadratic Weighted Kappa rate of 90.2% on the small-sized internal KHUMC dataset. The robustness of the RCA stream is also evaluated by the single-modal Messidor dataset, of which the obtained mean Accuracy (94.8%) and Area Under Receiver Operating Characteristic (99.4%) outperform those of the state-of-the-arts significantly. Utilizing a network strongly regularized at feature space to learn the amalgamation of different modalities is of proven effectiveness. Thanks to the widespread availability of multi-modal retinal imaging for each diabetes patient nowadays, such approach can reduce the heavy reliance on large quantity of labeled visual data. Our TFA-Net is able to coordinate hybrid information of fundus photos and wide-field SS-OCTA for exhaustively exploiting DR-oriented biomarkers. Moreover, the embedded feature-wise augmentation scheme can enrich generalization ability efficiently despite learning from small-scale labeled data.