En Face Optical Coherence Tomography Angiography Research Articles

Reduction of Optic Disc Microvasculature and Retinal Nerve Fiber Layer Thinning in Patients with Glaucoma

PurposeTo assess the relationship between the change of optic disc vessel density (ODVD) and retinal nerve fiber layer (RNFL) thinning in primary open-angle glaucoma (POAG) patients. DesignRetrospective case series. MethodsFor 105 POAG patients, ≥ 5 consecutive optical coherence tomography (OCT) and OCT angiography (OCTA) images were obtained during ≥ 2 years of follow-up.Based on enface OCTA imaging, ODVD was calculated as the ratio of pixels occupied by vessels below the internal limiting membrane within the temporal area of the optic cup, and ODVD reduction was determined when there was a statistically significant negative slope (P < 0.05) for any of the global, superior, or inferior sectors. The association between the rates of ODVD change and RNFL thinning was assessed by multivariable longitudinal linear mixed-effects model vs. time. ResultsDuring 2.9 ± 0.3 years of follow-up on the 105 participants with visual field mean deviation at baseline of 5.7 ± 4.8 dB, 46 (43.8%) showed ODVD reduction. Faster global RNFL thinning was associated with the smaller Bruch's membrane opening area (ß = 0.381; 95% confidence interval (CI), 0.120 to 0.646; P = 0.006), optic disc hemorrhage (ß = -0.567; 95% CI, -0.909 to -0.228; P = 0.002) and faster rate of global ODVD change (ß = -0.090; 95% CI, -0.139 to -0.042; P = 0.001). ConclusionsReduction of optic disc microvasculature was associated with rapid RNFL thinning in POAG. This suggests a role for deep ONH circulation in the glaucoma pathogenesis.

Multimodal imaging of a case of retinal cavernous hemangioma.

Herein, we reported a case of retinal cavernous hemangioma (RCH) and its multimodal imaging. Many grape-like lesions were incidentally found along the distal portion of the vascular arcade in a 23-year-old man's superonasal quadrant of the retina. The best-corrected visual acuity was 20/20 in both eyes. The fluorescein angiography showed saccular lesions that slowly filled with hypofluorescence in the early stage and clusters of aneurysms with hyperfluorescence and a special "fluorescein cap" appearance in the late stage. The optical coherence tomography angiography (OCTA) B-scan revealed multilocular cavernous spaces with different sizes in the inner retinal layers, varying signals, and an epiretinal membrane. The enface OCTA of retina showed grape-like changes and multiple highly reflective signal cavities with clear and complete boundaries. Different multimodal images are better for understanding the characteristics of RCH and more convenient for its diagnosis and follow-up.

Retinal capillary perfusion heterogeneity in diabetic retinopathy detected by optical coherence tomography angiography

BackgroundDiabetic retinopathy (DR) is a leading cause of blindness and involves retinal capillary damage, microaneurysms, and altered blood flow regulation. Optical coherence tomography angiography (OCTA) is a non-invasive way of visualizing retinal vasculature but has not been used extensively to study blood flow heterogeneity. The purpose of this study is to detect and quantify blood flow heterogeneity utilizing en-face swept source OCTA in patients with DR.MethodsThis is a prospective clinical study which examined patients with either type 1 or 2 diabetes mellitus. Each included eye was graded clinically as no DR, mild DR, or moderate-severe DR. Ten consecutive en face 6 × 6 mm foveal SS-OCTA images were obtained from each eye using a PLEX Elite 9000 (Zeiss Meditec, Dublin, CA). Built-in fixation-tracking, follow-up functions were utilized to reduce motion artifacts and ensure same location imaging in sequential frames. Images of the superficial and deep vascular complexes (SVC and DVC) were arranged in temporal stacks of 10 and registered to a reference frame for segmentation using a deep neural network. The vessel segmentation was then masked onto each stack to calculate the pixel intensity coefficient of variance (PICoV) and map the spatiotemporal perfusion heterogeneity of each stack.ResultsTwenty-nine eyes were included: 7 controls, 7 diabetics with no DR, 8 mild DR, and 7 moderate-severe DR. The PICoV correlated significantly and positively with DR severity. In patients with DR, the perfusion heterogeneity was higher in the temporal half of the macula, particularly in areas of capillary dropout. PICoV also correlates as expected with the established OCTA metrics of perfusion density and vessel density.ConclusionPICoV is a novel way to analyze OCTA imaging and quantify perfusion heterogeneity. Retinal capillary perfusion heterogeneity in both the SVC and DVC increased with DR severity. This may be related to the loss of retinal capillary perfusion autoregulation in diabetic retinopathy.

Evaluating the diagnostic performance with neurovascular segregation of the retinal nerve fibre layer in glaucoma

Aims/Purpose: To evaluate the diagnostic performance in detecting eyes with glaucoma by segregating the neuronal and vascular components in circumpapillary optical coherence tomography (OCT) and OCT angiography (OCTA) scans.Methods: In this study, 93 participants with glaucoma were age‐ and gender‐matched with normal controls with no ocular diseases. OCT and OCTA volumetric images of one eye from each participant were acquired using a prototype high resolution swept source OCT imaging system (Zeiss PlexElite) using a 6 mm x 6 mm imaging protocol centered at the optic nerve head. Circumpapillary OCT and OCTA images with a diameter of 3.46 mm were subsequently generated. Information from the circumpapillary and enface OCTA images were used to isolate and segregate the vascular components from the circumpapillary retinal nerve fibre layer (RNFL), which was obtained using a deep learning segmentation approach. Thicknesses of the RNFL with and without the vascular components were measured and diagnostic performance was evaluated using area under the receiving operating characteristic curve (AUC) analysis. Both global and quadrant (superior, inferior, nasal and temporal) measurements around the optic nerve head were considered.Results: Imaging data of one eye from 154 healthy and 143 glaucoma participants were acquired. Using only the global RNFL thickness, the detection of glaucoma achieved an AUC of 0.877 ± 0.021. With the vascular components excluded from the global RNFL thickness, an AUC of 0.890 ± 0.020 was obtained. When the vascular and non‐vascular components of the RNFL in the different quadrants were modelled separately, AUC improved to 0.927 ± 0.015, and was found to be significantly higher than the detection of glaucoma using global measures (p &lt; 0.001).Conclusions: Segregation of vascular and non‐vascular components in the retinal nerve fibre layer led to an improvement in glaucoma detection. Further improvements were observed when the contributions of the components in the RNFL quadrants were modelled separately.

Effects of diabetic retinopathy on longitudinal morphological changes in AMD-associated type 1 macular neovascularization

The purpose of this study was to investigate the effect of diabetic retinopathy (DR) on longitudinal morphological changes in AMD-associated type 1 macular neovascularization using optical coherence tomography angiography (OCTA). We enrolled fifty treatment-naïve eyes with a diagnosis of exudative AMD and type 1 MNV. Twenty of 50 eyes were affected by mild DR. En face OCT angiography were examined for the MNV lesion area (mm2), the MNV flow area (mm2), the central macular thickness (CMT) and the BCVA. The OCTA acquisition was performed at the following visits: (i) before the loading phase (LP) of intravitreal injection of aflibercept (T1), and (ii) 1 month after the last intravitreal injection of loading phase comprising 3 monthly injections (T2). All morpho-functional parameters showed a significantly change at T2 compared to T1 values in both groups. Furthermore, we found a greater MNV area reduction after LP in eyes without DR (P = 0.023). With regard to the remaining parameters, no significant changes were found between two groups (P > 0.05). Our analysis revealed a less MNV area reduction after loading dose of anti-VEGF therapy in eyes affected by diabetic retinopathy.

Optimizing the OCTA layer fusion option for deep learning classification of diabetic retinopathy.

The purpose of this study is to evaluate layer fusion options for deep learning classification of optical coherence tomography (OCT) angiography (OCTA) images. A convolutional neural network (CNN) end-to-end classifier was utilized to classify OCTA images from healthy control subjects and diabetic patients with no retinopathy (NoDR) and non-proliferative diabetic retinopathy (NPDR). For each eye, three en-face OCTA images were acquired from the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) layers. The performances of the CNN classifier with individual layer inputs and multi-layer fusion architectures, including early-fusion, intermediate-fusion, and late-fusion, were quantitatively compared. For individual layer inputs, the superficial OCTA was observed to have the best performance, with 87.25% accuracy, 78.26% sensitivity, and 90.10% specificity, to differentiate control, NoDR, and NPDR. For multi-layer fusion options, the best option is the intermediate-fusion architecture, which achieved 92.65% accuracy, 87.01% sensitivity, and 94.37% specificity. To interpret the deep learning performance, the Gradient-weighted Class Activation Mapping (Grad-CAM) was utilized to identify spatial characteristics for OCTA classification. Comparative analysis indicates that the layer data fusion options can affect the performance of deep learning classification, and the intermediate-fusion approach is optimal for OCTA classification of DR.

Effect of red-light therapy on retinal and choroidal blood perfusion in myopic children.

To investigate the effect of repeated low-level red-light therapy (RLRLT) on retinal and choroidal blood perfusion in myopic children. Forty-seven myopic children (mean spherical equivalent refractive error [SE]: -2.31 ± 1.26 D; age range: 8.0-11.0 years) were enrolled and received RLRLT (power 2 mW, wavelength 650 nm) for 3 min twice a day, while 20 myopic children (SE: -2.75 ± 0.84 D; age range: 7.0-10.0 years) were included as a control group. All participants wore single-vision distance glasses. Refractive error, axial length (AL) and other biometric parameters were measured at baseline and during follow-up visits in the first, second and fourth weeks after initiation of treatment. Retinal thickness, subfoveal choroidal thickness (SFCT), total choroidal area (TCA), luminal area (LA), stromal area (SA) and choroidal vascularity index (CVI) were obtained using optical coherence tomography (OCT). The percentage retinal vascular density (VD%) and choriocapillaris flow voids (FV%) were measured using en-face OCT angiography. After 4 weeks of treatment, a significant increase in SFCT was observed in the RLRLT group, with an average increase of 14.5 μm (95% confidence interval [CI]: 9.6-19.5 μm), compared with a decrease of -1.7 μm (95% CI: -9.1 to 5.7 μm) in the control group (p < 0.0001). However, no significant changes in retinal thickness or VD% were observed in either group (all p > 0.05). In the OCT images from the RLRLT group, no abnormal retinal morphology related to photodamage was observed. Thehorizontal scans revealed an increase in TCA, LA and CVI over time (all p < 0.05), while SA and FV% remained unchanged (both p > 0.05). These findings indicate that RLRLT can enhance choroidal blood perfusion in myopic children, demonstrating a cumulative effect over time.

The big warp: Registration of disparate retinal imaging modalities and an example overlay of ultrawide-field photos and en-face OCTA images.

To develop an algorithm and scripts to combine disparate multimodal imaging modalities and show its use by overlaying en-face optical coherence tomography angiography (OCTA) images and Optos ultra-widefield (UWF) retinal images using the Fiji (ImageJ) plugin BigWarp. Optos UWF images and Heidelberg en-face OCTA images were collected from various patients as part of their routine care. En-face OCTA images were generated and ten (10) images at varying retinal depths were exported. The Fiji plugin BigWarp was used to transform the Optos UWF image onto the en-face OCTA image using matching reference points in the retinal vasculature surrounding the macula. The images were then overlayed and stacked to create a series of ten combined Optos UWF and en-face OCTA images of increasing retinal depths. The first algorithm was modified to include two scripts that automatically aligned all the en-face OCTA images. The Optos UWF image could easily be transformed to the en-face OCTA images using BigWarp with common vessel branch point landmarks in the vasculature. The resulting warped Optos image was then successfully superimposed onto the ten Optos UWF images. The scripts more easily allowed for automatic overlay of the images. Optos UWF images can be successfully superimposed onto en-face OCTA images using freely available software that has been applied to ocular use. This synthesis of multimodal imaging may increase their potential diagnostic value. Script A is publicly available at https://doi.org/10.6084/m9.figshare.16879591.v1 and Script B is available at https://doi.org/10.6084/m9.figshare.17330048.

Unilateral Multifocal Focal Choroidal Excavation

Aim: To describe an unusual OCT image of FCE. Methods: This is retrospective research. 23 cases (25 eyes) of FCE were observed by SD-OCT and en-face OCT angiography (OCTA). Among all patients, there were 16 males and 7 females, and the age range is from 19 to 77 years old. Institutional review board approval and informed consent from patient was obtained. Results: Among the 23 patients assessed, unilateral multifocal focal choroidal excavation was found in 2 eyes of 2 patients. Multiple FCEs were distributed outside the fovea at varying distances from the fovea however did not involve the fovea. Unilateral multifocal FCEs can occur relatively far from the fovea and vary in size and depth. Unilateral multifocal FCEs correspond to each other on SD-OCT and en-face OCT images. Conclusion: FCE can appear simultaneously in the same fundus in a multifocal form and does not involve the fovea, which is rare in FCE.

En-face widefield optical coherence tomography angiography for understanding vascular networks changes in two cases of acute retinal necrosis

PurposeThe present study assesses the utility of en-face widefield optical coherence tomography angiography (OCTA) imaging for evaluating the retinal vascular network during the course of treatment in acute retinal necrosis(ARN).ObservationsOCTA images of two cases of acute retinal necrosis were analyzed. Case 1 was a 15-year-old male with visual crowding in his right eye who had best-corrected visual acuity of 16/20 and intraocular pressure of 25 mmHg in his right eye on initial evaluation. Case 2 was a 57-year-old male with visual crowding in his left eye who had best-corrected visual acuity of 20/20 in his left eye on initial examination and intraocular pressure of 19.3 mmHg.In both patients, dynamic changes could be tracked by en-face ultra-widefield OCTA imaging before and up to 1 year after surgical treatment. The images showed arteriovenous anastomosis and the nonperfused area on the surface of the retina.Conclusions and importanceEn-face widefield OCTA is useful for monitoring the structure of retinal vessels over time in acute retinal necrosis. Wide-angle OCTA is used to non-invasively examine retinal vascular dynamic changes in ARN. OCTA artifacts due to intraocular inflammation appeared, making interpretation difficult. These will remain as issues in the future. It seems difficult for a while to completely replace FA due to the problem of image clarity.

Retinal Vascular Tortuosity Index Change after Idiopathic Epiretinal Membrane Surgery: Does Internal Limiting Membrane Peeling Affect Retinal Vascular Tortuosity?

Idiopathic epiretinal membrane (iERM) surgery is one of the most commonly performed vitreoretinal surgeries, and the issue of internal limiting membrane (ILM) peeling in ERM surgery is still controversial. The aims of this study are to evaluate the changes in retinal vascular tortuosity index (RVTI) after pars plana vitrectomy for the iERM using optical coherence tomography angiography (OCTA) and to assess whether ILM peeling has an additional effect on RVTI reduction. This study included25 eyes of 25 iERM patients who underwent ERM surgery. The ERM was removed without ILM peeling in 10 eyes (40.0%), and the ILM was peeled in addition to the ERM in 15 eyes (60.0%). The existence of the ILM after ERM peeling was checked with second staining in all eyes. Best corrected visual acuity (BCVA) and 6 × 6 mm en-face OCTA images were recorded before surgery and at the first month postoperatively. A skeleton model of the retinal vascular structure was created following Otsu binarization of en-face OCTA images using ImageJ software (1.52U). RVTI was calculated as the ratio of each vessel length to its Euclidean distance on the skeleton model using the Analyze Skeleton plug-in. The mean RVTI declined from 1.220 ± 0.017 to 1.201 ± 0.020 (p = 0.036) in eyes with ILM peeling and from 1.230 ± 0.038 to 1.195 ± 0.024 in eyes without ILM peeling (p = 0.037). There was no difference between the groups in terms of postoperative RVTI (p = 0.494). A statistically significant correlation was found between postoperative RVTI and postoperative BCVA (rho = 0.408, p = 0.043). The RVTI is an indirect indicator of the traction created by the iERM on retinal microvascular structures, and it was effectively reduced after iERM surgery. The postoperative RVTIs were similar in cases who underwent iERM surgery with or without ILM peeling. Therefore, ILM peeling may not have an additive effect on the loosening of microvascular traction and thus may be reserved for recurrent ERM surgeries.

MULTI-MODAL IMAGING IN DIFFUSE SUBRETINAL FIBROSIS WITH UVEITIS SYNDROME.

To describe clinical features including multimodal imaging in a case of diffuse subretinal fibrosis and uveitis syndrome. A young patient presented with counting fingers in both eyes due to posterior uveitis and unresponsive to systemic corticosteroids. Ultra-wide field pseudo-color and autofluorescence imaging, optical coherence tomography angiography (OCT-A), en-face OCT-A, and spectral-domain optical coherence were performed. Clinical examination revealed a bilateral fibrosis plaque in both fovea and macular multifocal choroidal lesions associated, with no vitritis. Ultra-wide field-autofluorescence allowed us to determine activity showing a hyperfluorescent pattern. En-face OCT-A at the level of the ellipsoid layer showed multiple hyperreflective lesions surrounding a hyperreflective fibrosis plaque in both eyes, which improved and stabilized during the follow-up. Optical coherence tomography angiography at the level of retina pigmentary epithelium-choriocapillaris revealed neocapillary network changes along the chronification of the disease. The patient required the addition of intravitreal dexamethasone implants (Ozurdex) to control the acute rebounds and anti-TNFα to control the underlying inflammatory process. This is the first diffuse subretinal fibrosis with uveitis syndrome reported with a complete En-face OCT-A and OCT-A examination. This multi-modal imaging will improve the monitoring of the disease's activity and the chronicity changes.

Reconstruction and Visualization of 5μm Sectional Coronal Views for Macula Vasculature in OptoVue OCTA

A Computerized Medical Image Processing (CMIP) method is proposed to address the current challenges of optical coherence tomography angiography (OCTA): (1) the need for observing the macula vasculature concerning natural curvature of the macula region; (2) the need for generating OCTA frames at successive small depths in all macula layers; and (3) the need for enhancing the visibility of blood vessels, particularly below the outer retina region. The proposed CMIP method involves image preprocessing, reconstruction, and enhancement stages. Twenty subjects were obtained from the OCTA500 dataset, which was obtained from the OptoVue OCTA machine. The 20 subjects comprise the two OCTA fields of view (FOV), right and left eyes (OD and OS), and five common macula disorders. The sequential enface OCTA images at 5μm macula depths were displayed. The presentation of the macula vasculature was enhanced at all depths. The resulting new ophthalmic views enable: (1) avoiding the superimposition of macula vasculature into a projection map; (2) enhancing the OCTA presentation of blood vessels; and (3) inspecting the macula’s 3D oval-shaped. The proposed CMIP method can generate sectional macula coronal views (MCV) for every 5μm depth, clarifying the macula’s curvature in a way that has not been presented in OCTA machines. Therefore, “tracking” the 3D propagation of the blood vessel network at all macula depths becomes possible. Furthermore, the blood vessels’ display at all macula depths, including the deep choroid layers, is enhanced. The method yields futuristic ophthalmic advantages that would allow the physician to precisely inspect the 3D localization and diffusion of the macula disorders. The method is invariant to the OCTA’s FOVs, macula disorder, and OD or OS eye.

A Comparative Study of Choroidal Vascular and Structural Characteristics of Typical Polypoidal Choroidal Vasculopathy and Polypoidal Choroidal Neovascularization: OCTA-Based Evaluation of Intervortex Venous Anastomosis

The aim of this study was to compare the choroidal characteristics of typical polypoidal choroidal vasculopathy (T-PCV) and polypoidal choroidal neovascularization (P-CNV) cases, and to investigate the presence of intervortex venous anastomoses in these PCV subtypes by using en face optical coherence tomography angiography (OCTA). A total of 35 eyes of 33 PCV cases were included. The PCV cases were divided into T-PCV and P-CNV groups. The choroidal vascularity index (CVI) was calculated. En face OCTA images were evaluated for the presence of intervortex venous anastomoses. The diameter of the largest anastomotic Haller vessel was measured. T-PCV cases had significantly higher mean CVI values (73.9 ± 3.7 vs. 70.8 ± 4.5%) than P-CNV cases (p = 0.039). Intervortex venous anastomoses were observed in 85.7% of T-PCV eyes and in 91.7% of P-CNV eyes on en face OCTA (p = 1.000). In the cases with intervortex venous anastomosis, the mean diameter of the largest anastomotic vessel on en face OCTA was 341.2 ± 109.1 µm in the T-PCV and 280.4 ± 68.4 µm in the P-CNV group (p = 0.048). The higher CVI value in T-PCV may be an important feature concerning the pathogenesis and classification of PCV. Although there was no difference between the two subtypes in terms of intervortex anastomosis, more dilated anastomotic vessels were observed in the T-PCV.

Morphological Changes in the Foveal Avascular Zone after Panretinal Photocoagulation for Diabetic Retinopathy Using OCTA: A Study Focusing on Macular Ischemia

Background and objectives: This study aimed to analyze the morphological changes in the foveal avascular zone (FAZ) after panretinal photocoagulation (PRP) in patients with diabetic retinopathy, with a particular focus on the presence or absence of comorbid diabetic macular ischemia (DMI), using optical coherence tomography angiography (OCTA). Materials and Methods: Treatment-naïve 25 eyes of 16 patients who received PRP were examined in this retrospective case series. FAZ area, perimeter, and circularity were calculated on a 3 × 3-mm en-face OCTA image before PRP (baseline) and 1 and 3 months after PRP. The patients were divided into two groups according to coexisting DMI, and each group was statistically analyzed. Results: In patients with DMI (9 eyes), FAZ area significantly decreased from the baseline to 3 months after PRP (0.86 ± 0.56 to 0.61 ± 0.31 mm2, p = 0.018), whereas FAZ perimeter and circularity remained unchanged following treatment (p = 0.569 and 0.971, respectively). In patients without DMI (16 eyes), FAZ parameters did not show statistically significant changes across the 3-month follow-up period. Conclusion: PRP significantly reduces FAZ area in patients with DMI.

PERIVASCULAR FLOWER-BUD-LIKE LESIONS ON EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN PATIENTS WITH VITREORETINAL LYMPHOMA.

To describe perivascular flower-bud-like lesions (PFBLs) as novel characteristics of vitreoretinal lymphoma on en face optical coherence tomography (OCT) angiography. A retrospective chart review was performed on 23 consecutive patients (35 eyes), who had biopsy-proven vitreoretinal lymphoma between January 2018 and March 2021. En face OCT angiography images were analyzed before and after intervention. PFBLs were initially identified on midretinal slabs of en face OCT angiography, and were further characterized by other imaging modalities. Perivascular flower-bud-like lesions were detected in 12 eyes (34.3%) of 8 patients, of which 8 eyes had best-corrected visual acuity of 20/40 or better. In 10 of the 12 eyes, PFBLs were detected within 6 months of symptom onset. On en face OCT angiography, PFBLs presented as punctate points or confluent bands surrounding retinal vessels, with arterial and venous involvement. In 4 of the 12 eyes, arteries were mainly affected. On OCT B-scans, PFBLs commonly appeared as hyperreflective full-thickness intraretinal lesions that colocalized with subretinal pigment epithelium deposits (3 eyes, 25%) and retinal pigment epithelium irregularities (4 eyes, 33.3%). However, PFBLs could not always be identified on other imaging modalities such as fundus photographs and fundus fluorescein angiography. In all eyes with follow-up, PFBLs attenuated or resolved months after receiving chemotherapy or diagnostic vitrectomy. PFBLs are characteristic imaging findings of vitreoretinal lymphoma and may facilitate an early diagnosis of vitreoretinal lymphoma, which would in turn lead to more timely and effective treatment.

X-linked retinoschisis: OCT-angiography in two brothers from a four-generation family with a p.Arg197Cys pathogenic variant in the RS1 gene.

X-linked juvenile retinoschisis (XLRS) is a rare genetic disease causing retinal splitting. The aim of this work is to describe the optical coherence tomography angiography (OCTA) features in two brothers affected by an hemizygous c.589C>T (p.Arg197Cys) pathogenic variant in exon 6 of the RS1 gene. Each patient underwent a complete ophthalmological examination, including measurement of best corrected visual acuity, slit-lamp biomicroscopy, fundus color photographs, fundus autofluorescence and infrared imaging, fluorescein angiography, spectral-domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCTA). En Face SD-OCT and OCTA revealed the presence of two different pattern of cystic lesions, fusiform and oval, disposed on a petaloid or irregular manner in the perifoveolar area. A widening of the foveal avascular zone with interruption of the vascular arcades was clearly evident. Furthermore, a capillary drop-out was observed in the superficial plexus of the central retina, other than capillary ectasia in the deep capillary plexus. Straight gray lines were visible among the cysts. OCTA data herein described allow a detailed morphological evaluation of XLRS other than a quantitative assessment of retinal capillary flow in this disease. The retinal alterations that we have reported may be helpful to better understand this rare condition with OCTA being a sensitive technique to monitor the evolution of the disease and the response to potential future therapeutic approaches aimed to restore vision.

Correlation of Diabetic Disease Severity to Degree of Quadrant Asymmetry in En Face OCTA Metrics.

PurposeTo determine if diabetic retinopathy (DR) severity affects quadrant asymmetry (QA) of optical coherence tomography angiography (OCTA) metrics differentially.MethodsNinety eyes (60 patients) with no diabetes mellitus (DM) (n = 39) or varying levels of DR (n = 51) had OCTA images (3 × 3 mm, Cirrus5000) acquired five times and averaged. The vessel length density (VLD) and perfusion density (PD) of the superficial retinal layer (SRL) and deep retinal layer (DRL) were measured. QA was defined as the maximum minus minimum value among four parafoveal Early Treatment Diabetic Retinopathy quadrants, and compared with DR severity by linear regression including fixed effects for each individual and eye.ResultsThe mean patient age was 55.5 years (range, 24–88 years) and 60% were male. Comparing severe nonproliferative DR or proliferative DR versus no DM/DR eyes, QA was significantly higher for SRL VLD, and PD (+0.67 ± 0.16 and +0.014 ± 0.003; P < 0.001) and DRL VLD, and PD (+1.25 ± 0.16 and +0.032 ± 0.003; P < 0.001). When comparing mild or moderate nonproliferative DR versus no DM/DR, the DRL VLD, and PD were significantly higher (+0.51 ± 0.13 and +0.015 ± 0.003; P < 0.001). For every step increase in DR severity, there was a +0.20 QA for SRL VLD, +0.004 SRL PD, +0.33 DRL VLD and +0.009 DRL PD (P < 0.001). Regression analysis comparing intraquadrant effect on DR severity demonstrated that the superior quadrant was most affected for all OCTA metrics.ConclusionsDR severity affects VLD and PD more asymmetrically across Early Treatment Diabetic Retinopathy quadrants with a linear increase in QA for each worsening level of DR. Individual intraeye metrics such as QA can accurately quantify DR severity without concerns for intereye variabilities that could affect the reproducibility and reliability of OCTA quantification.

Pentosan Polysulfate Sodium-Associated Maculopathy: Early Detection Using OCT Angiography and Choriocapillaris Flow Deficit Analysis

To compare choriocapillaris flow deficit (CC-FD) analysis using optical coherence tomography angiography (OCTA) in eyes of patients treated with high cumulative dosages of pentosan polysulfate sodium (PPS) but no signs of retinal toxicity versus healthy age-matched controls. Retrospective clinical cohort study. Patients treated with PPS for interstitial cystitis with a cumulative dose of > 1000 g underwent multimodal imaging screening to exclude evidence of PPS maculopathy or other retinal findings. All study patients and age-matched healthy controls completed a 3×3 mm macular volume scan OCTA using the SOLIX full-range OCT. En face OCTA images at the level of the CC were exported and CC-FDs were computed and compared between groups. Fifteen patients treated with PPS and 15 age-matched controls were included. The mean PPS cumulative dose was 1974 ± 666 g over a mean of 17.6 ± 6.8 treatment years. All patients registered a visual acuity of 20/25 or better and normal fundus autofluorescence (FAF), OCT, multicolor, near-infrared reflectance (NIR), and ultra-widefield fundus color and autofluorescence images. The CC-FD was 32.7 ± 3.6% in the PPS group compared with 28.6 ± 4.3% in the control group (P=.023). Patients treated with PPS long enough to accumulate dosages > 1000 g showed significant CC flow impairment before the development of macular toxicity signs with OCT, NIR, and FAF compared with age-matched normal controls. Thus, the choroid may be the earliest manifestation of ocular toxicity, predating the development of clinically evident retinal pigment epithelium (RPE) injury. The subsequent RPE disruption may be the result of choriocapillaris impairment or primary PPS toxicity. Assessment of the CC on OCTA may be a useful tool for early detection of toxicity, although further longitudinal studies are required.

Normative Data and Determinants of Macular, Disc, and Peripapillary Vascular Density in Healthy Myopic Children Using Optical Coherence Tomography Angiography.

ObjectiveTo establish a normative database for the vascular density (VD) in macular, disc, and peripapillary regions in healthy myopic children and to evaluate associated ocular features with optical coherence tomography angiography (OCTA).MethodsThis was an observational, prospective and cross-sectional study. 776 Chinese healthy myopic children (375 boys and 401 girls) were enrolled, mean (±SD) age 9.84 ± 1.98 (range 6–16) years. En-face angiogram OCTA was performed on 6 mm × 6 mm retinal and 4.5 mm × 4.5 mm disc regions. VD measurements in the macular retina were segmented into the four regions: superficial capillary plexus (SCP), intermediate capillary plexus (ICP), deep capillary plexus (DCP), and choriocapillaris (CC). Correlations between macular, disc, and peripapillary VD and possible influencing factors [age, gender, axial length (AL), spherical equivalent refraction (SER), right/left eye, and signal strength index (SSI)] were assessed by Pearson’s correlation and multivariate regression analysis.ResultsFor macular scans, the corrected VD in the ICP region was (48.25 ± 4.24)% for the whole macular retina. The macular ICP VD in most sections was lower than the SCP, DCP, and CC (all P < 0.001). The corrected VD in CC was (72.96 ± 4.42)% for the whole macular retina. The macular CC VD in every section was all higher than the SCP, ICP, and DCP (all P < 0.001). The size of foveal avascular zone (FAZ) and foveal VD 300 (FD-300) was 0.28 mm2± 0.10 mm2 and (58.43 ± 4.17)% respectively. For disc scans, the corrected VD was (58.04 ± 2.73)% for the whole disc area. Both AL and SER were strongly correlated with ICP, DCP, and CC VD in all regions (all P < 0.01). Larger SSI was correlated with a lower VD in the SCP and ICP, and a higher VD in DCP and CC (all P < 0.01).ConclusionVascular density values provide large scale normative data on macular, disc, and peripapillary vascular parameters in a large sample of healthy myopic children with OCTA measured in the four different retinal plexuses and regions. The VD in different regions had various influencing factors; mainly a close correlation with AL and SSI.