Characteristics Of Choroidal Neovascularization Research Articles

Choroidal neovascularization in children: Etiology, diagnosis, and clinical manifestations

Few studies have analyzed choroidal neovascularization (CNV) in children because of the low incidence of this complication in pediatric ophthalmology. However, given the significant effect on visual acuity and diagnostic difficulties in children, the study of this complication is relevant.
 AIM: This study aimed to analyze the etiological structure and clinical features of CNV in children.
 MATERIAL AND METHODS: From 2014 to 2022, 61 eyes of 54 children (26 girls and 28 boys) had CNV. The patients underwent standard ophthalmologic examination and optical coherence tomography (OCT) and OCT angiography (OCTA) of the macular zone and optic disc using the RS-3000 Advance 2 Tomograph (Nidek, Japan).
 RESULTS: At the time of CNV diagnosis, the children were 5–17 years old, with a mean of 11±3 years. In 30 children (55.6%), CNV was caused by inflammatory lesions of the retina and choroid. Of these cases, 11 occurred during remission, whereas 21 occurred alongside pathologies of the retina, choroid, and optic nerve of noninflammatory genesis (8 of which were associated with Best’s disease). In three children, CNV was considered idiopathic. The development time of postinflammatory CNV ranged from 1 month to 12 years, with an average of 7.3±5 months from disease onset. Type 2 CNV was found in most cases (48 eyes, 78.7%).
 CONCLUSION: CNV is a rare complication of various ocular diseases in children. In our cohort, it was most frequently observed in children with inflammatory lesions of the retina and choroid, even during remission. Patients at risk of CNV must be actively monitored because it occurs in various forms.

Characterization of Vascular Morphology of Neovascular Age-Related Macular Degeneration by Indocyanine Green Angiography.

Age-related macular degeneration (AMD) is a leading cause of blindness among older individuals, and its prevalence is rapidly increasing due to the aging population. Choroidal neovascularization (CNV) or wet AMD, which accounts for 10%-20% of all AMD cases, is responsible for an alarming 80%-90% of AMD-related blindness. Current anti-VEGF therapies show suboptimal responses in approximately 50% of patients. Resistance to anti-VEGF treatment in CNV patients is often associated with arteriolar CNV, while responders tend to have capillary CNV. While fluorescein angiography (FA) is commonly used to assess leakage patterns in wet AMD patients and animal models, it does not provide information about CNV vascular morphology (arteriolar CNV vs. capillary CNV). This protocol introduces the use of indocyanine green angiography (ICGA) to characterize lesion types in laser-induced CNV mouse models. This method is crucial for investigating the mechanisms and treatment strategies for anti-VEGF resistance in wet AMD. It is recommended to incorporate ICGA alongside FA for comprehensive assessment of both leakage and vascular features of CNV in mechanistic and therapeutic studies.

LONG-TERM PROGNOSIS OF CHOROIDAL NEOVASCULARIZATION COMPLICATING ANGIOID STREAKS.

To report the very long-term visual prognosis of choroidal neovascularization complicating angioid streaks in the antivascular endothelial growth factor era. Retrospective monocentric study aimed at analyzing patients' demographics, choroidal neovascularization features, angioid streak-associated conditions, and previous and current therapies for choroidal neovascularization. The main outcome measures were the quantitative measurement of central retinal pigment epithelial atrophy enlargement by comparing the ratio of pixels involved on automated infrared images acquired by spectral-domain optical coherence tomography and the changes in best-corrected visual acuity. The secondary outcome measures were the number of intravitreal injections and the changes in central choroidal thickness and central retinal thickness. Subgroup analyzes were performed to compare macular atrophy extent between eyes of patients with or without proven pseudoxanthoma elasticum ("PXE" or "no PXE") and between eyes previously treated or not with photodynamic therapy ("PDT" or "no PDT"). Thirty-three eyes of 23 patients were included. The mean best-corrected visual acuity decreased significantly from 66 ± 19 Early Treatment Diabetic Retinopathy Study letters at the time of the first antivascular endothelial growth factor injection to 52 ± 23 Early Treatment Diabetic Retinopathy Study letters at the end of the follow-up (mean follow-up duration: 109 ± 42 months, range: 47-175 months). The ratio of central retinal pigment epithelial atrophy enlargement was 201%, 110%, 240%, and 111% in the PXE, no PXE, PDT, and no PDT groups, respectively. Despite the use of antivascular endothelial growth factor agents, the very long-term prognosis appeared relatively poor, especially in patients with PXE. This study also suggests that PDT should be used with caution in the management of choroidal neovascularization in eyes with angioid streaks.

CNV-Net: Segmentation, Classification and Activity Score Measurement of Choroidal Neovascularization (CNV) Using Optical Coherence Tomography Angiography (OCTA)

This paper aims to present an artificial intelligence-based algorithm for the automated segmentation of Choroidal Neovascularization (CNV) areas and to identify the presence or absence of CNV activity criteria (branching, peripheral arcade, dark halo, shape, loop and anastomoses) in OCTA images. Methods: This retrospective and cross-sectional study includes 130 OCTA images from 101 patients with treatment-naïve CNV. At baseline, OCTA volumes of 6 × 6 mm2 were obtained to develop an AI-based algorithm to evaluate the CNV activity based on five activity criteria, including tiny branching vessels, anastomoses and loops, peripheral arcades, and perilesional hypointense halos. The proposed algorithm comprises two steps. The first block includes the pre-processing and segmentation of CNVs in OCTA images using a modified U-Net network. The second block consists of five binary classification networks, each implemented with various models from scratch, and using transfer learning from pre-trained networks. Results: The proposed segmentation network yielded an averaged Dice coefficient of 0.86. The individual classifiers corresponding to the five activity criteria (branch, peripheral arcade, dark halo, shape, loop, and anastomoses) showed accuracies of 0.84, 0.81, 0.86, 0.85, and 0.82, respectively. The AI-based algorithm potentially allows the reliable detection and segmentation of CNV from OCTA alone, without the need for imaging with contrast agents. The evaluation of the activity criteria in CNV lesions obtains acceptable results, and this algorithm could enable the objective, repeatable assessment of CNV features.

Multimodal Imaging Based Predictors for the Development of Choroidal Neovascularization in Patients with Central Serous Chorioretinopathy

This study evaluated predictors for choroidal neovascularization (CNV) associated with central serous chorioretinopathy (CSCR) based on multimodal imaging. A retrospective multicenter chart review was conducted on 134 eyes of 132 consecutive patients with CSCR. Eyes were classified as per the multimodal imaging-based classification of CSCR at baseline into simple/complex CSCR and primary episode/recurrent/resolved CSCR. Baseline characteristics of CNV and predictors were evaluated with ANOVA. In 134 eyes with CSCR, 32.8% had CNV (n = 44) with 72.7% having complex CSCR (n = 32), 22.7% having simple (n = 10) and 4.5% having atypical (n = 2). Primary CSCR with CNV were older (58 vs. 47, p = 0.00003), with worse visual acuity (0.56 vs. 0.75, p = 0.01) and of longer duration (median 7 vs. 1, p = 0.0002) than those without CNV. Similarly, recurrent CSCR with CNV were older (61 vs. 52, p = 0.004) than those without CNV. Patients with complex CSCR were 2.72 times more likely to have CNV than patients with simple CSCR. In conclusion, CNV associated with CSCR was more likely in complex CSCR and older age of presentation. Both primary and recurrent CSCR are implicated in CNV development. Patients with complex CSCR were 2.72 times more likely to have CNV than patients with simple CSCR. Multimodal imaging-based classification of CSCR supports detailed analysis of associated CNV.

Characteristics of choroidal neovascularization in elderly eyes with high myopia not meeting the pathologic myopia definition

The META-Analysis of Pathologic Myopia Study group proposed a new classification system for myopic maculopathy (MM) with pathologic myopia (PM) defined as MM equal to/more serious than diffuse atrophy or the presence of plus lesions and myopic choroidal neovascularization (mCNV) defined as CNV in the eye with PM. However, CNV in elderly eyes with high myopia (HM) not meeting the PM definition (high-myopia CNV) are not classified as age-related macular degeneration (nAMD) or mCNV. This retrospective study included 39 eyes with high-myopia CNV, 20 eyes with mCNV, and 20 eyes with AMD. All patients were at least 40 years old. We compared the clinical characteristics and treatment outcomes among three groups. The high-myopia CNV group had significantly more CNV types, shorter axial length and fewer lacquer cracks (P < 0.0001, respectively); larger baseline greatest linear dimension (P = 0.0002), more fellow-eye drusen (P = 0.0106), more men (P = 0.0029), and more treatments (24 months, P = 0.0098) compared to the mCNV group. Compared with the nAMD group, the high-myopia CNV group was significantly younger (P = 0.0041), and had fewer CNV types (P = 0.0316), more lacquer cracks (P = 0.0079) and fewer drusen (affected-eye, P = 0.0006 and fellow-eye, P = 0.0222), and fewer treatments (24 months, P = 0.0030). Because the CNV in elderly eyes with HM not meeting the PM definition is classified as combined mCNV and nAMD, the clinical and angiographic findings are critical to determine the treatment strategy.

Subthreshold Exudative Choroidal Neovascularization (CNV): Presentation of This Uncommon Subtype and Other CNVs in Age-Related Macular Degeneration (AMD).

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in people over the age of 50 worldwide. Exudative or neovascular AMD is a more severe subset of AMD which is characterized by the presence of choroidal neovascularization (CNV). Recent advancements in multimodal ophthalmic imaging, including optical coherence tomography (OCT) and OCT-angiography (OCT-A), have facilitated the detection and characterization of previously undetectable neovascular lesions and have enabled a more refined classification of CNV in exudative as well as nonexudative AMD patients. Subthreshold exudative CNV is a novel subtype of exudative AMD that typically presents asymptomatically with good visual acuity and is characterized by stable persistent or intermittent subretinal fluid (SRF). This review aims to provide an overview of the clinical as well as multimodal imaging characteristics of CNV in AMD, including this new clinical phenotype, and propose effective approaches for management.

Malondialdehyde-Modified Photoreceptor Outer Segments Promote Choroidal Neovascularization in Mice.

PurposeThis study aimed to establish a novel choroidal neovascularization (CNV) mouse model through subretinally injecting malondialdehyde (MDA)-modified photoreceptor outer segments (POS), which was more consistent with the pathogenesis of wet age-related macular degeneration (AMD).MethodsMDA-modified POS were subretinally injected in C57BL/6J mice. Four weeks later, to assess the volume of CNV and the morphology of retinal pigment epithelium (RPE), isolectin B4 and zonula occludens-1 antibody were used for immunostaining. Fundus fluorescent angiography and optical coherence tomography imaging were used to describe the morphologic features of CNV. Transepithelial resistance was measured on polarized ARPE-19 cells. Vascular endothelial growth factor levels in the cell culture medium were detected by enzyme-linked immunosorbent assay. The protein and messenger RNA expression levels of autophagy markers were measured using Western blot and quantitative polymerase chain reaction.ResultsCNV and RPE atrophy were successfully induced in the mouse model. MDA-modified POS also significantly increased the expression of vascular endothelial growth factor and disrupted cell junctions in RPE cells. In addition, MDA-modified POS induced autophagy–lysosomal impairment in RPE cells.ConclusionsSubretinal injection of MDA-modified POS may generate a feasible CNV model that simulates the AMD pathological process.Translational RelevanceThis study expands the understanding of the role of MDA in AMD pathogenesis, which provides a potential therapeutic target of AMD.

OPTICAL COHERENCE TOMOGRAPHY FEATURES OF CHOROIDAL NEOVASCULARIZATION AND THEIR CORRELATION WITH AGE, GENDER, AND UNDERLYING DISEASE.

To investigate the influence of age, gender, and underlying disease on the optical coherence tomography (OCT) features of choroidal neovascularization (CNV) secondary to inflammation, myopia (mCNV), and age-related macular degeneration (AMD-CNV). Demographic and clinical data of eyes with treatment-naive inflammatory CNV, mCNV, and Type 2 AMD-CNV were collected. Optical coherence tomography images were reviewed to determine the presence of pitchfork sign, pigment epithelial detachment, subretinal fluid (SRF), intraretinal cysts, subretinal hyperreflective material, atrophy, and outer retinal disruption graded 1 to 4. The influence of demographics and underlying etiology on OCT signs was investigated. One hundred and eighty-five eyes from 179 patients were enrolled. The mean [SD] age was 36 [±14.4], 62 [±18], and 77 [±8] for the inflammatory CNV, mCNV, and AMD-CNV, respectively (P < 0.001). Multiple linear regression showed that the presence of pitchfork sign was negatively associated with age (P < 0.0001), regardless of underlying disease. By contrast, the SRF, pigment epithelial detachment, intraretinal cysts, and the outer retinal disruption were all positively influenced by age, regardless of gender and underlying disease (all P < 0.01). Logistic regression showed that none of the OCT signs increased the likelihood for diagnosis of inflammatory CNV. By contrast, the absence of SRF was suggestive for mCNVs, and the presence of pigment epithelial detachment and SRF was suggestive for AMD-CNVs. The age of the patient had a significant effect on the OCT appearance of the CNV, particularly the presence of a pitchfork sign, regardless of the underlying etiology. The absence of SRF was suggestive for a diagnosis of mCNVs. The presence of SRF and pigment epithelial detachment was suggestive for AMD-CNVs.

The morphology of choroidal neovascularization in chronic central serous chorioretinopathy presenting with flat, irregular pigment epithelium detachment

PurposeTo evaluate morphological characteristics of choroidal neovascularization in chronic central serous chorioretinopathy (CSC) presenting with flat and irregular pigment epithelium detachment (FIPED) by means of innovative multimodal imaging.MethodsIn this observational cross-sectional study, we examined 10 consecutive patients affected by chronic CSC and FIPED using fluorescein angiography (FA), indocyanine-green angiography (ICGA) and optical coherence tomography angiography (OCTA). A qualitative analysis of the nature and characteristics of neovascular membrane was performed, combining available multimodal imaging and literature data.ResultsMultiple areas of retinal pigment epithelium alterations, macular hypo- and hyperpigmentation and atrophic areas were identified. Spectral domain OCT (SD-OCT) showed subretinal fluid in 80% of eyes and the ‘double layer sign’ in all patients. Late FA phases showed staining areas without leakage in all eyes; ICGA showed a hyperfluorescent plaque with surrounding hypofluorescence in 80% of patients. OCTA detected characteristic neovascular networks in the outer retina within the FIPEDs, classified as filamentous vessels with a pruned tree-like pattern in five eyes and a tangled pattern in three eyes. The choriocapillaris network showed dark areas in 80% of eyes and diffuse dark spots in all eyes.ConclusionMultimodal imaging completes clinical characterization of FIPEDs in chronic CSC. This study using OCTA technology describes the phenotype of hidden neovascular lesions in shape and morphology.

Choroidal neovascularization fusion visualization for spectral-domain optical coherence tomography and optical coherence tomography angiography images.

The spectral-domain optical coherence tomography (SD-OCT) images and OCT angiography (OCTA) images can provide complementary information for choroidal neovascularization (CNV) visualization. We expected to simultaneously display multifaceted characteristics of CNV in a single projection image. We proposed a fusion method for CNV visualization by combining structural and angiographic images, which mainly involves four steps: (a) Generate SD-OCT and OCTA projection images from original volumetric data with retinal layer restriction. (b) For SD-OCT projection images, enhance retinal vessels and CNV. (c) For OCTA images, detect CNV region based on multimodal data and display the neovascularization in false color. (d) A maximum fusion strategy was adopted to generate the fused images. Experimental results with 30 cases from 30 patients demonstrate that the fused images are more effective in displaying CNV than single-modality projection images. The average information entropy and the mean gradient in the CNV regions for SD-OCT projection images, OCTA images, and the fusion images are 4.66/0.21, 5.45/0.45, and 6.8/0.58, respectively. The proposed method is more effective for CNV visualization than the conventional single-modality image-based method. The proposed method can combine complementary information from multimodal images and provide a satisfying visual effect.

OCTA evaluation of treatment-naïve flat irregular PED (FIPED)-associated CNV in chronic central serous chorioretinopathy before and after half-dose PDT.

To qualitatively and quantitatively evaluate the features of treatment-naïve flat irregular pigment epithelial detachment (FIPED)-associated choroidal neovascularization (CNV) in chronic central serous chorioretinopathy (CSC) using swept-source (SS) optical coherence tomography angiography (OCTA) before and after half-dose photodynamic therapy (PDT). Retrospective case series. The multimodal imaging data of the eyes with FIPED-associated CNV in chronic CSC were reviewed. The features of FIPED-associated CNVs were evaluated by SS-OCTA. Records of twenty-one patients (21 eyes) were reviewed. The mean age was 56.62 ± 6.87 years. After half-dose PDT, all patients have improved best spectacle-corrected visual acuity from 0.49 at baseline to 0.25 at 6-month visit, and subfoveal choroidal thickness decreased with subretinal fluids absorbed. By OCTA, the features of CNV at baseline included long filamentous linear vessels (21/21), branching into other large mature vessels with rare anastomoses (21/21); and/or a 'dead tree' appearance at the vessel's termini (20/21); and no perilesional hypointense halo (21/21). Compared to those at baseline, the mean vessel density of CNV showed no significant change at 1-,3-,6-month follow-up, while the mean area of CNV was significantly larger at the 6-month follow-up (p = 0.013). OCT angiography allows to qualitatively and quantitatively evaluate CNV in chronic CSC. The features of FIPED-associated CNV on OCTA illustrated its quiescent characteristic and further guided therapy. Half-dose PDT showed favorable effects on chronic CSC complicated with FIPED-associated CNV.

Angiofluorographic Characteristics of Choroidal Neovascularization associated with Pathologic Myopia.

Purpose: To evaluate the incidence of choroidal neovascularization (CNV) in high myopic patients who experienced recent visual loss and to describe the characteristics of CNV that develop as a complication of pathologic myopia and were detected by fluorescein angiography (FA).Material and methods: The fluorescein angiograms of 89 patients with high myopia, who registered a recent decrease of visual acuity were reviewed. The incidence of CNV was evaluated and its angiofluorographic appearance described. Results: 172 eyes of 89 patients (six eyes were excluded for different reasons: anophthalmia, dense cataract, history of retinal detachment surgery) were analyzed. Among 89 patients (63 females, 26 males), in 58 cases (~65%), the angiofluorography revealed the presence of a neovascular membrane, and 8 cases presented bilateral CNV. That made a total of 66 eyes. The majority of CNVs were classic (56%), 20% had an occult pattern and 24% were cicatricial. The location was predominantly subfoveal.Conclusions: Considering that the main cause for visual loss in myopic patients is the new-onset myopic CNV, fluorescein angiography should be performed in cases with recent visual loss. When CNV is suspected, FA can demonstrate the presence of myopic CNV, bringing information regarding the type, area, and activity of the CNV and helping exclude other disorders. Due to its location, predominantly sub- or juxtafoveal and to the extended retinal lesions associated with pathologic myopia, the visual prognosis of these patients is poor despite new active treatments.

Особенности хориоидальной неоваскуляризации при патологической миопии

Особенности хориоидальной неоваскуляризации при патологической миопии

IA-net: informative attention convolutional neural network for choroidal neovascularization segmentation in OCT images.

Choroidal neovascularization (CNV) is a characteristic feature of wet age-related macular degeneration (AMD). Quantification of CNV is useful to clinicians in the diagnosis and treatment of CNV disease. Before quantification, CNV lesion should be delineated by automatic CNV segmentation technology. Recently, deep learning methods have achieved significant success for medical image segmentation. However, some CNVs are small objects which are hard to discriminate, resulting in performance degradation. In addition, it's difficult to train an effective network for accurate segmentation due to the complicated characteristics of CNV in OCT images. In order to tackle these two challenges, this paper proposed a novel Informative Attention Convolutional Neural Network (IA-net) for automatic CNV segmentation in OCT images. Considering that the attention mechanism has the ability to enhance the discriminative power of the interesting regions in the feature maps, the attention enhancement block is developed by introducing the additional attention constraint. It has the ability to force the model to pay high attention on CNV in the learned feature maps, improving the discriminative ability of the learned CNV features, which is useful to improve the segmentation performance on small CNV. For accurate pixel classification, the novel informative loss is proposed with the incorporation of an informative attention map. It can focus training on a set of informative samples that are difficult to be predicted. Therefore, the trained model has the ability to learn enough information to classify these informative samples, further improving the performance. The experimental results on our database demonstrate that the proposed method outperforms traditional CNV segmentation methods.

Outcomes by Baseline Choroidal Neovascularization Features in Age-Related Macular Degeneration: A Post Hoc Analysis of the VIEW Studies

To assess the influence of baseline choroidal neovascularization (CNV) features on visual change and fluid resolution after anti-vascular endothelial growth factor (VEGF) treatment of eyes with neovascular age-related macular degeneration (nAMD). Post hoc analysis of 52-week data from the phase 3 Vascular Endothelial Growth Factor VEGF Trap-Eye: Investigation of Efficacy and Safety in Wet Age-Related Macular Degeneration (AMD) Studies (VIEW) 1 and 2 clinical trials. One thousand eight hundred four patients with nAMD. Integrated data from VIEW 1 and 2 of 1804 eyes receiving intravitreal aflibercept injections (IAIs) 2 mg every 4 weeks, IAIs 2 mg every 8 weeks after 3 initial monthly doses, and ranibizumab every 4 weeks with documented baseline CNV type, total area, and leakage area were analyzed. Time to an event and cumulative incidence were evaluated by Kaplan-Meier analysis, and relative risks were estimated using proportional hazards analysis. Cumulative incidence of time to first sustained vision gain of 15 or more Early Treatment Diabetic Retinopathy Study letters, vision loss of more than 5 Early Treatment Diabetic Retinopathy Study letters from baseline, as well as first sustained absence of retinal fluid and intraretinal fluid as evaluated by OCT with respect to CNV type, total CNV, and leakage area. Eyes with predominantly classic CNV (mean best-corrected visual acuity [BCVA], 48.2 letters at baseline) showed a higher incidence rate of first sustained gain of 15 letters or more than eyes with occult CNV (mean BCVA, 57.9 letters at baseline; P < 0.01). Eyes with occult CNV at baseline showed higher incidence rates of first sustained absence of retinal fluid and of intraretinal fluid than eyes with predominantly classic CNV (both P < 0.01). With increasing baseline CNV total area and leakage area, the incidence rate of first sustained gain of 15 letters or more decreased. This post hoc analysis provided additional evidence for the role of baseline CNV features (CNV type, total area, and leakage area) in influencing visual and anatomic outcomes in eyes with nAMD after anti-VEGF treatment.

Choroidal nevus and polypoidal vasculopathy: case series

BackgroundTo report an association between choroidal nevus and polypoidal choroidal vasculopathy (PCV) in three patients.Case presentationWe have encountered 3 isolated patients in our center presenting with subretinal exudation and a choroidal nevus that were thoroughly evaluated by slit lamp biomicroscopy, fundus photos, Fluorescein angiography (FA), indocyanine green angiography (ICG), B-scan ultrasound, and optical coherence tomography (SD-OCT—Heidelberg). The classic features of choroidal neovascularization seen on PVC were present in all 3 patients, all of whom had a substantial response to intravitreous antiangiogenic agent. OCT, Fluorescein and ICG Angiography, and Fundus autofluorescence (FAF) revealed similar findings in all cases.Discussion and conclusionsWe have identified a clinical pattern of PCV and choroidal nevus that can be diagnosed early using fluorescein angiography, ICG and OCT.

A new rat model of treatment-naive quiescent choroidal neovascularization induced by human VEGF165 overexpression.

ABSTRACTVascular endothelial growth factor (VEGF) is a crucial stimulator for choroidal neovascularization (CNV). Our aim was to develop a reproducible and valid treatment-naive quiescent CNV (i.e. without signs of exudation and with normal visual acuity) rat model by subretinal injection of an adeno-associated virus (AAV)-VEGFA165 vector. The CNV development was longitudinally followed up in vivo by scanning laser ophthalmoscopy/optical coherence tomography, fluorescein and Indocyanine Green angiographies and ex vivo by electron microscopy (EM) and immunohistochemistry. In total, 57 eyes were analysed. In vivo, a quiescent CNV was observed in 93% of the eyes 6 weeks post-transduction. In EM, CNV vessels with few fenestrations, multi-layered basement membranes and bifurcation of endothelial cells were observed sharing the human CNV features. Human VEGF overexpression, multi-layered retinal pigment epithelium (RPE) (RPE65) and macrophages/activated microglia (Iba1) were also detected. In addition, 19 CNV eyes were treated for up to 3 weeks with bevacizumab. The retinal and CNV lesion thickness decreased significantly in bevacizumab-treated CNV eyes compared with untreated CNV eyes 1 week after the treatment. In conclusion, our experimental CNV resembles those seen in patients suffering from treatment-naive quiescent CNV in wet age-related macular degeneration (AMD), and responds to short-term treatment with bevacizumab. Our new model can, therefore, be used to test the long-term effect of new drugs targeting CNV under precisely-defined conditions.

Detection of Choroidal Neovascularization by Optical Coherence Tomography Angiography with Assistance from Use of the Image Segmentation Method

Optical coherence tomography angiography (OCTA) is a popular medical imaging technology that can quickly establish a three-dimensional model of the fundus without dye injection. However the number of images in a model is quite large, so finding the lesions through image processing technology can greatly reduce the time required for the judgment of the condition. This paper proposes a method for finding choroidal neovascularization (CNV) in OCTA images. Among the several characteristics of CNV, the larger turning angle of blood vessels is a relatively clear feature, so we will use this property to find out whether there is CNV in an OCTA image. We will transform the color space to CIELAB space, and extract the L-channel prior to preceding to the next step. We will then use some image segmentation methods to find the clearer vessel region. Finally, we will detect the CNV through certain morphology methods. The experimental result shows that our proposed method can effectively find the CNV in the OCTA image, meaning that we can make automated judgments through this method in the future and reduce the time necessary for human judgment.

Optical coherence tomography angiography characteristics of choroidal neovascularization requiring varied dosing frequencies in treat-and-extend management: An analysis of the AVATAR study.

PurposeTo evaluate optical coherence tomography angiography (OCTA) characteristics of choroidal neovascularization (CNV) in eyes requiring different treatment frequency of anti-vascular endothelial growth factor (VEGF) therapy for neovascular age-related macular degeneration (NVAMD).DesignProspective observational case series.MethodsSubjects who had undergone anti-VEGF treatment for NVAMD in the AVATAR study were subdivided into 3 groups depending on required anti-VEGF dosing: (i) treat-and-extend requiring every 4–6 weeks dosing (TEq4-6w), (ii) treat-and-extend requiring every 7–12 weeks dosing (TEq7-12w), (iii) eyes not requiring injection within last 12 months (PRN >12mo). OCTA images were evaluated for the morphological characteristics of CNV and the choriocapillaris flow void.ResultsStudy consisted 40 eyes of 31 patients with a mean age of 79.9 ± 6.2 years. CNV morphology analysis on OCTA was feasible in 29 (73%) eyes. Ninety percent of CNVs in TEq7-12w group were irregular in shape involving foveal center, while 67% of CNVs in PRN>12mo group were circular in shape sparing foveal center. Among three groups, statistical difference was found in CNV shape (P = .012) and CNV location (P = .003), while no statistical difference was found in the CNV area (P = .14), vessel density (P = .19), presence of core vessels (P = .23), the presence of small margin loops (P = .20), large margin loops (P = .14), CNV maturity (P = .40), or the mean percentage of choriocapillaris area with flow void (P = .66).ConclusionThe combination of CNV sparing the foveal center with higher circularity may suggest a clinically inactive CNV following initial anti-VEGF therapy. We found minimal distinguishing OCTA characteristics between those eyes that required ongoing therapy with the treat-and-extend regimen. More research is needed to identify specific CNV characteristics on OCTA that may become a useful tool for the management of NVAMD and timing of treatment.