Assessment of Exudative Activity of Choroidal Neovascularization in Age-Related Macular Degeneration by OCT Angiography

DEEP LEARNING FOR AUTOMATIC PREDICTION OF EARLY ACTIVATION OF TREATMENT-NAIVE NONEXUDATIVE MACULAR NEOVASCULARIZATIONS IN AGE-RELATED MACULAR DEGENERATION

BACKGROUND

Around 30% of nonexudative macular neovascularizations exudate within 2 years from diagnosis in patients with age-related macular degeneration. The aim of this study is to develop a deep learning classifier based on optical coherence tomography (OCT) and OCT angiography (OCTA) to identify nonexudative macular neovascularizations at risk of exudation.

METHODS

Patients with age-related macular degeneration showing OCTA and fluorescein angiography-documented nonexudative macular neovascularization with a 2-year minimum imaging follow-up were retrospectively selected. Patients showing OCT B-scan-documented macular neovascularization exudation within the first 2 years formed the EX GROUP while the others formed the QU GROUP. ResNet-101, Inception-ResNet-v2, and DenseNet-201 were independently trained on OCTA and OCT B-scan images. Combinations of the six models were evaluated with major and soft voting techniques.

RESULTS

Eighty-nine eyes of 89 patients with a follow-up of 5.7 ± 1.5 years were recruited (35 EX GROUP and 54 QU GROUP). Inception-ResNet-v2 was the best performing among the three single convolutional neural networks. The major voting model resulting from the association of the three different convolutional neural networks resulted in an improvement of performance both for OCTA and OCT B-scan (both significantly higher than human graders' performance). The soft voting model resulting from the combination of OCTA and OCT B-scan-based major voting models showed a testing accuracy of 94.4%. Peripheral arcades and large vessels on OCTA en face imaging were more prevalent in the QU GROUP.

CONCLUSION

Artificial intelligence shows high performances in identifications of nonexudative macular neovascularizations at risk for exudation within the first 2 years of follow-up, allowing better customization of follow-up timing and avoiding treatment delay. Better results are obtained with the combination of OCTA and OCT B-scan image analysis.

Analyzing Formation and Absorption of Avascular Subretinal Hyperreflective Material in nAMD From OCTA-Based Insights

PURPOSE

To investigate the formation and absorption of avascular subretinal hyperreflective material (avSHRM) in neovascular age-related macular degeneration (nAMD) based on optical coherence tomography angiography (OCTA) characteristics.

DESIGN

Prospective cohort study.

METHODS

This study included patients with treatment-naive nAMD who were followed up for 3 months. Subjects were classified into an avSHRM group and a non-avSHRM group based on the presence of avSHRM at baseline. Quantitative OCTA characteristics including explant area, perimeter, vessel area, density, length, junctions, endpoints, lacunarity, maximum vessel caliber, vessel dispersion, and fractal dimension were assessed, and 3-dimensional volume and optical density ratio (ODR) of avSHRM were measured. Comparison analyses, correlation coefficients, and regression models were applied to explore factors associated with avSHRM formation and absorption.

RESULTS

A total of 88 eyes from 88 patients (39 female) were enrolled. Compared to the non-avSHRM group, the avSHRM group exhibited a more intricate vasculature, characterized by higher values of macular neovascularization (MNV) perimeter, vessel area, total vessel length, total number of junctions, and total number of endpoints (all P < .05), as well as the maximum vessel caliber (P < .001). In the multivariate model, which was adjusted for age, sex, and types of medications, avSHRM absorption was correlated with baseline average vessel length, maximum vessel caliber, and avSHRM ODR (standardized β = 0.274, -0.367, and -0.334; P = .049, .010, and .018, respectively), with an adjusted R² of 0.453.

CONCLUSIONS

Quantitative OCTA measurements can be used for assessing the dynamics of avSHRM in nAMD. Patients with more complex vasculature are at higher risk for avSHRM formation. Average vessel length, maximum vessel diameter, and avSHRM ODR play a role in its absorption.

Comparative study of widefield swept-source optical coherence tomography angiography in eyes with concomitant age-related macular degeneration and diabetic retinopathy

BACKGROUND/AIMS

We sought to evaluate widefield swept-source optical coherence tomography angiography (WF SS-OCTA) among eyes with concomitant age-related macular degeneration (AMD) and diabetes mellitus or diabetic retinopathy (DM/DR).

METHODS

This cross-sectional, comparative study consisted of three study groups: eyes with (1) AMD and DM/DR, (2) AMD alone and (3) DM/DR alone. WF SS-OCTA (3×3, 6×6 and 12×12 mm) images were captured. Vascular metrics included foveal avascular zone (FAZ), vessel density (VD) and vessel skeletonised density (VSD). Mixed-effects multivariable regression models adjusted for age were performed by cohort and subgroup based on AMD and DR stages.

RESULTS

Our cohort included 287 eyes from 186 patients with an average age of 64±14.0 years old. Results revealed significantly reduced vascular metrics in concomitant AMD and DM/DR eyes (N=68) compared with AMD-only eyes (N=71) on all angiograms but not compared with DM/DR-only eyes (N=148). For example, when compared with AMD-only eyes, AMD and DM/DR eyes had significantly reduced VD (β=-0.03, p=0.016) and VSD (β=-1.09, p=0.022) on 12×12 mm angiograms, increased FAZ perimeter (β=0.51, p=0.025) and FAZ area (β=0.11, p=0.015) on 6×6 mm angiogram, and reductions in all VD and VSD metrics on 3×3 and 6×6 mm angiograms. However, only 3×3 mm angiogram FAZ metrics were significantly different when comparing DM/DR eyes with concomitant AMD and DM/DR eyes.

CONCLUSION

WF SS-OCTA revealed significant reductions in retinal microvasculature metrics in AMD and DM/DR eyes compared with AMD-only eyes but not compared with DM/DR-only eyes.

Quantitative response of macular neovascularisation to loading phase of aflibercept in neovascular age-related macular degeneration

PURPOSE

To evaluate quantitative morphological changes in macular neovascularisation (MNV) network after aflibercept therapy in neovascular age-related macular degeneration (nAMD) patients.

METHODS

Consecutive treatment-naïve patients with optical coherence tomography (OCT) angiography confirmed MNV due to nAMD who completed a loading phase of intravitreal aflibercept injections. A quantitative analysis of the vascular network remodelling was performed using a computational software (Angiotool).

RESULTS

A total of 53 eyes of 52 patients were included in the analysis. The total MNV area decreased significantly after three aflibercept injections (p = 0.003). Total vessel area and vessel density decreased respectively of 20% and 12% at V3 (p < 0.001 in both cases). Other parameters that reduced significantly were total vessel length, average vessel length and density of vascular junctions (p = 0.018, p = 0.002, and p = 0.044, respectively). The number of vascular endpoints (p = 0.001) and lacunarity (p = 0.011) increased significantly, whilst the number of vascular junctions did not vary significantly (p = 0.068). Changes in vascular metrics were predominantly driven by MNV type 1 and 2. No clear relationship was observed between any of the vascular metrics and the macular fluid status.

CONCLUSION

Although objective quantification of vascular parameters showed a significant remodelling of the MNV post-loading phase of aflibercept in type 1 and 2 MNV subtypes, none of the quantified vascular metrics correlated to the macular fluid response. These findings highlight a dissociation of anti-angiogenic and anti-permeability properties of aflibercept therapy during the loading phase.

Pachychoroid neovasculopathy versus macular neovascularization in age-related macular degeneration with and without shallow irregular pigment epithelial detachment

To compare the choroidal neovascular features of individuals with pachychoroid neovasculopathy (PNV) and neovascular age-related macular degeneration (nAMD) with and without shallow irregular pigment epithelial detachment (SIPED). Using optical coherence tomography angiography, the choroidal neovascular complexes of 27 patients with PNV, 34 patients with nAMD and SIPED, and 15 patients with nAMD without SIPED were analyzed with FIJI and AngioTool software. PNV compared to nAMD with SIPED had a greater vessel percentage area (P = 0.034), junction density (P = 0.045), average vessel length (P < 0.001), and fractal dimension (P < 0.001). PNV, compared to nAMD without SIPED, had a greater total vessel length (P = 0.002), total number of junctions (P < 0.001), junction density (P = 0.034), and fractal dimension (P = 0.005). nAMD with SIPED, compared to nAMD without SIPED, had greater vessel area, total number of junctions, total vessel length, and average vessel length (all P values < 0.001). Patients with nAMD plus SIPED and individuals with nAMD without SIPED have similar fractal dimension values (P = 0.703). Biomarkers of choroidal neovascular complexity, such as fractal dimension, can be used to differentiate PNV from nAMD with or without SIPED.

MULTIMODAL IMAGING IN NONEXUDATIVE CHOROIDAL NEOVASCULARIZATION: A Pilot Study of Status of Retinal Pigment Epithelium

PURPOSE

To study the status of retinal pigment epithelium in nonexudative and active choroidal neovascularization (CNV) in neovascular age-related macular degeneration.

METHODS

Only treatment-naïve neovascular age-related macular degeneration patients were enrolled in this prospective case-control study, including 17 eyes with nonexudative CNV (6 males and 11 females, 74.9 ± 10.0 years) and 28 eyes with active CNV (8 males and 20 females, 69.3 ± 6.8 years). All patients received a comprehensive ophthalmic examination, optical coherence tomography, dark-field scanning laser ophthalmoscopy, and fundus autofluorescence. The status of the retinal pigment epithelium was assessed with ImageJ software as the brightness of the CNV region on transillumination optical coherence tomography, dark-field scanning laser ophthalmoscopy, and fundus autofluorescence images. Choroidal neovascularization vessel density was measured based on optical coherence tomography angiography.

RESULTS

The brightness of CNV region in nonexudative CNV was statistically significantly lower than in active CNV with both optical coherence tomography transillumination ( P = 0.004) and dark-field scanning laser ophthalmoscopy ( P = 0.0015). No difference in brightness of the CNV region between nonexudative and active CNV was found based on fundus autofluorescence ( P = 0.44). The vessel density of nonexudative CNV was statistically significantly higher than that of active CNV with a median value of 64.5% (95% confidential interval [CI] 53.4-79.0%) and 55.3% (95% CI 52.2-60.0%), respectively ( P = 0.05).

CONCLUSION

Multimodal imaging revealed substantial alteration of the retinal pigment epithelium in active CNV but not in nonexudative CNV which correlates with the higher vessel density of nonexudative CNV.

Optical coherence tomography angiography biomarkers in a bi-monthly maintenance dosing aflibercept in patients with neovascular age-related macular degeneration

PURPOSE

To evaluate the correlations between swept-source optical coherence tomography angiography (SS-OCTA) parameters and clinical outcomes in eyes with neovascular age-related macular degeneration (nAMD) administered a bimonthly intravitreal aflibercept regimen.

METHODS

This prospective, single-arm, interventional study enrolled 33 patients with treatment-naïve nAMD. The eyes received three monthly aflibercept injections followed by five bi-monthly regimens (total 50 weeks). The structural parameters including central subfield thickness (CST) and 5 mm pigment epithelial detachment (PED) volume and microvascular parameters including macular neovascularization (MNV) area, vessel density (VD), and vessel length density (VLD) were recorded every before and 1 week after treatment.

RESULTS

Patients who gained > 5 letters of best-corrected visual acuity (BCVA) from the baseline showed greater decreases in VD and VLD during the loading phase. Patients without recurrent or persistent fluid during the maintenance phase showed greater decreases in CST and 5 mm PED volume after the first injection. The decrease in mean VD during the loading phase was significantly correlated with the final BCVA (r = -0.820, p = 0.004). Moreover, the decrease in mean VLD during the loading phase was significantly correlated with the improvement in the final BCVA (r = -0.726, p = 0.017).

CONCLUSIONS

The decrease in mean VD during the loading phase was significantly negatively correlated with the final BCVA at the last visit. The decrease in mean VLD during the loading phase, mean CST during the loading phase, and the improvement in final BCVA showed significant correlations. Therefore, early changes in OCTA microvascular and OCT structural parameters could help predict clinical outcomes in nAMD.

TRIAL REGISTRATION

The trial was registered with the Clinical Research Information Service (CRIS), which joined the WHO International Clinical Trials Registry Platform (ICTRP) (Registration number: KCT0007375, Date of first trial registration: 10/06/2022).

Growth of nonexudative macular neovascularization in age-related macular degeneration: an indicator of biological lesion activity

PURPOSE

To investigate the growth of nonexudative macular neovascularization (MNV) in age-related macular degeneration (AMD) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

Patients with treatment-naïve nonexudative AMD in one eye and exudative AMD in the fellow eye who underwent SS-OCTA imaging for at least 12 months were retrospectively reviewed. The MNV area measurement was quantified in eyes with treatment-naïve nonexudative MNV using ImageJ for analysing the correlation between MNV growth and the onset of exudation, as well as evaluating the consistency of the MNV growth rate during the subclinical and exudative stages. Kaplan-Meier survival analysis and logistic regression analyses were used.

RESULTS

In total, 45 eyes with treatment-naïve nonexudative AMD from 45 patients were enrolled. Treatment-naïve nonexudative MNV was identified in 21 eyes (46.67%) at baseline. The development of exudative findings was noted in eight eyes (17.78%), including six eyes with previously noted nonexudative MNV. Eyes with growing MNV (increase in area ≥50% within 12 months) had an increased risk of exudation and developed exudation earlier than eyes with stable MNV (13.60 [6.43-20.77] months versus 31.11 [26.61-35.62] months, P < 0.0001, Log-rank test). Consistent growth pattern of MNV lesions was further identified in eyes with growing MNV during anti-VEGF treatment.

CONCLUSION

SS-OCTA allows to qualitatively and quantitatively evaluate nonexudative MNV in AMD patients. Growing MNV involved higher probabilities and a faster onset of exudation compared to stable MNV. Identifying the growth of MNV on OCTA might be helpful for establishing treatment strategies and follow-up planning.

OCTA Biomarker Search in Patients with nAMD: Influence of Retinal Fluid on Time-Dependent Biomarker Response

PURPOSE

Previous studies have identified a link between optical coherence tomography (OCT)-derived and OCT angiography (OCTA)-based parameters in patients with neovascular AMD (nAMD); the latter may serve as direct biomarkers for macular neovascularization (MNV) activity. The aim of this study was to assess the individual influence of retinal thickness (RT) as well as intra- and sub-retinal fluid (IRF, SRF) presence on the treatment response over time as assessed by previously identified OCTA-derived MNV vascular parameters.

METHODS

During the first 3 months of anti-VEGF therapy patients were prospectively followed. RT, SRF and IRF were determined from SSOCT/A (PlexElite, Zeiss) images and using the semi-automated AngioTool software, vessel area (VA), total vessel length (TVL), total number of junctions (TNJ), junction density (JD), vessel density (VD) as well as MNV area were exported. IRF and SRF were identified manually on OCT volume scans .The associations between RT, IRF, and SRF and SSOCTA vascular parameters were analyzed using linear mixed models.

RESULTS

31 eyes of 31 patients with treatment-naïve and OCTA-positive nAMD MNV were included in this analysis. VA, TVL, TNJ, and MNV area show a statistically significant change over time in response to anti-VEGF treatment, even after correcting for the presence of SRF, IRF, or RT (all p < 0.05). This is not the case for JD and VD (both p > 0.05).

CONCLUSIONS

OCTA-based parameters VA, TVL, TNJ, and MNVarea show a strong response to anti-VEGF therapy over time, independent of the presence of IRF, SRF or RT. We conclude that the above listed OCTA parameters could contribute to our understanding of MNV biology and to guide individualized treatment in the future.

TRIAL REGISTRY

The authors confirm that all ongoing and related trials are registered. ClinicalTrials.gov Number: NCT02521142.

OCT and OCT Angiography Update: Clinical Application to Age-Related Macular Degeneration, Central Serous Chorioretinopathy, Macular Telangiectasia, and Diabetic Retinopathy

Similar to ultrasound adapting soundwaves to depict the inner structures and tissues, optical coherence tomography (OCT) utilizes low coherence light waves to assess characteristics in the eye. Compared to the previous gold standard diagnostic imaging fluorescein angiography, OCT is a noninvasive imaging modality that generates images of ocular tissues at a rapid speed. Two commonly used iterations of OCT include spectral-domain (SD) and swept-source (SS). Each comes with different wavelengths and tissue penetration capacities. OCT angiography (OCTA) is a functional extension of the OCT. It generates a large number of pixels to capture the tissue and underlying blood flow. This allows OCTA to measure ischemia and demarcation of the vasculature in a wide range of conditions. This review focused on the study of four commonly encountered diseases involving the retina including age-related macular degeneration (AMD), diabetic retinopathy (DR), central serous chorioretinopathy (CSC), and macular telangiectasia (MacTel). Modern imaging techniques including SD-OCT, TD-OCT, SS-OCT, and OCTA assist with understanding the disease pathogenesis and natural history of disease progression, in addition to routine diagnosis and management in the clinical setting. Finally, this review compares each imaging technique's limitations and potential refinements.

Predictive role of optical coherence tomography angiography for exudation recurrence in patients with type 1 neovascular age-related macular degeneration treated with pro-re-nata protocol

OBJECTIVES

We sought to identify the consecutive changes and predictive features for exudation recurrence in macular neovascularization (MNV) using optical coherence tomography angiography (OCTA) in type 1 neovascular age-related macular degeneration (NVAMD).

METHODS

A total of 291 OCTA images in consecutive visit of 45 patients newly diagnosed with type 1 NMV and treated with three loading intravitreal anti-vascular endothelial growth factor injections (IVIs) and a pro-re-nata (PRN) therapy regimen were analysed. Quantitative features of OCTA included the MNV area, MNV length, total number of endpoints (open-ended vessels) and junctions (internal branching) using AngioTool. Two subgroups were divided according to exudation recurrence time from the third IVI (group 1: ≤3 months vs. group 2: >3 months).

RESULTS

The area, length, number of total junctions, and endpoints decreased during three loading IVIs and increased at exudation recurrence (all p < 0.05). In a subgroup analysis of consecutive OCTA images, the number of total endpoints increased at two months prior to exudate recurrence in group 2 (the late recurrence group, p = 0.020). A higher total number of endpoints of MNV at baseline were found to be related with group 1 (early recurrence, p = 0.020 and 0.012 in univariate and multivariate regression analyses).

CONCLUSIONS

The MNV with higher open-ended vessels at the lesion periphery at baseline might be expected to show earlier recurrence of exudation after loading IVIs. By observing the number of open-ended vessels in consecutive OCTA images, exudation recurrence could be predicted.

Multimodal deep learning with feature level fusion for identification of choroidal neovascularization activity in age-related macular degeneration

PURPOSE

This study aimed to determine the efficacy of a multimodal deep learning (DL) model using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images for the assessment of choroidal neovascularization (CNV) in neovascular age-related macular degeneration (AMD).

METHODS

This retrospective and cross-sectional study was performed at a multicentre, and the inclusion criteria were age >50 years and a diagnosis of typical neovascular AMD. The OCT and OCTA data for an internal data set and two external data sets were collected. A DL model was developed with a novel feature-level fusion (FLF) method utilized to combine the multimodal data. The results were compared with identification performed by an ophthalmologist. The best model was tested on two external data sets to show its potential for clinical use.

RESULTS

Our best model achieved an accuracy of 95.5% and an area under the curve (AUC) of 0.9796 on multimodal data inputs for the internal data set, which is comparable to the performance of retinal specialists. The proposed model reached an accuracy of 100.00% and an AUC of 1.0 for the Ningbo data set, and these performance indicators were 90.48% and an AUC of 0.9727 for the Jinhua data set.

CONCLUSION

The FLF method is feasible and highly accurate, and could enhance the power of the existing computer-aided diagnosis systems. The bi-modal computer-aided diagnosis (CADx) system for the automated identification of CNV activity is an accurate and promising tool in the realm of public health.

Quantitative analysis of branching neovascular networks in polypoidal choroidal vasculopathy by optical coherence tomography angiography after photodynamic therapy and anti-vascular endothelial growth factor combination therapy

PURPOSE

To study serial changes in branching neovascular networks (BNN) by using optical coherence tomography angiography (OCTA) in patients with polypoidal choroidal vasculopathy (PCV) who underwent combined photodynamic therapy (PDT) and anti-vascular endothelial growth factor (anti-VEGF) therapy.

METHODS

In this retrospective study of 30 PCV patients who underwent combined therapy, OCTA images obtained at baseline and 1, 3, and 6 months after treatment were collected. The vessel area, vessel percentage area, average vessel length, and presence of polypoidal lesions on OCTA images as well as best-corrected visual acuity (BCVA), central retinal thickness (CRT), and central choroidal thickness (CCT) were recorded at each time point.

RESULTS

The BNN- and polypoidal lesion-detection rates on baseline OCTA images were 100% and 71%, respectively. The vessel area decreased during the first 3 months, and increased 6 months post-treatment, showing significant differences from baseline (p = 0.031). The vessel percentage area also reduced 1 and 3 months post-treatment (p = 0.025) and increased 6 months post-treatment. Continuous polypoidal lesion regression was observed from 1 to 3 and 6 months post-treatment (p = 0.031, p = 0.004, p = 0.002, respectively, in comparison with baseline). Patients with a decreasing vessel area over 6 months showed greater choroidal thickness than those with increasing vessel area (p = 0.004).

CONCLUSIONS

The BNN showed initial regression but were enlarged at 6 months after therapy. Patients showing continuous BNN regression showed a thicker choroid at baseline. This difference should be considered during treatment for PCV, and OCTA could be used for follow-up evaluations of PCV patients.

Quantitative OCT angiography findings according to pattern classification of type 1 neovascularization exudative age-related macular degeneration

OBJECTIVES

To define neovascularization (NV) patterns and their association with exudative activity in type 1 neovascular age-related macular degeneration (NVAMD).

METHODS

In optical coherence tomography angiography (OCTA) images of type 1 NVAMD, we stratified NV patterns according to whether they contained core vessel (C+/C-) and fine branching vessels (F+/F-) or not into C - F +, C + F +, and C + F - groups. Qualitative analyses assessing the status of peripheral tiny branching, inner branching capillaries, arcade, loop, and perilesional halo and quantitative analyses considering the NV area, length, density, and numbers of junctions and endpoints (open-ended vessels) in NV were conducted according to NV patterns and the presence of exudation on structural OCT.

RESULTS

Among 96 eyes, exudation was found in the C - F + (33.3%) and C + F + (47.6%) groups, related to peripheral tiny branching in both groups (p = 0.022 and p < 0.001) and perilesional halo in the C + F + group (p < 0.001). Peripheral arcades, inner branching capillaries, and loops were observed in more than half (68.3%, 58.7%, and 69.8%) in the C + F + group but not related with exudative activity in the C + F + group. In quantitative analysis, the number of endpoints was associated with exudation in univariate and multivariate analyses (p = 0.011 and p = 0.016) in C + F + group.

CONCLUSIONS

After pattern classification, type 1 NV patterns with fine branching vessels were considered to have exudative activity compared to NV without fine branching. The quantitative analysis of type 1 NV according to patterns showed the presence of peripheral tiny branching vessels was associated with NV activity.

Optical coherence tomography angiography features of macular neovascularization in wet age-related macular degeneration: A cross-sectional study

Background

OCT-A is a recent imaging technique allowing a non-invasive assessment of the retinal and choroidal microvasculature, providing valuable data for the diagnosis and monitoring of wet AMD. We aim to determine the diagnosis accuracy, describe the morphological features, and assess the clinical activity of MNV in wet AMD using OCT-A.

Materials and methods

We conducted a descriptive cross-sectional study over a 15-month period. We enrolled patients with treatment-naive and treated MNV secondary to wet AMD. Macular OCT-A images were obtained using a swept-source OCT-A device (Triton SS-OCT, Topcon, Tokyo, Japan). Morphologic characteristics and semi-automated measurements were analyzed on the en face projection OCT-Angiograms. For the qualitative analysis, determined the sensitivity of detection of the MNV using OCTA. When detected, we described its shape, branching pattern, anastomoses and loops, and vessel termination. We looked for the halo sign and the feeder vessel. We then defined the lesion's "pattern" reflecting its exudative activity. For the quantitative analysis, we measured the lesion's area in square millimeters, when its borders were clearly defined.

Results

70 eyes from 55 patients were enrolled in this study. Type 1 MNV was identified in 57,1% eyes, type 2 in 21,4%, mixed type 1 and2 in 1,4%, type 3 in 1,4% and unclassified fibrotic MNV in 18,6%. 55,7% were active and 44,3% were inactive. Sensitivity of detection was 85% for type 1 lesions, 100% for type 2, mixed and type 3 lesions, and 92% for unclassified fibrotic lesions. It was 84,6% for active lesions and 96,8% for inactive lesions. For each detected lesion, shape was well-defined (medusa, glomerulus, seafan), long liner vessels or ill-defined. Branching pattern was dense or loose. Anastomoses and vascular loops were numerous or few. Termination was in an anastomotic arcade or in a dead-tree aspect. Halo sign was present or absent and feeder vessel was detected or not. All types combined, 41,3% of the lesions were "pattern I" and 58,7% were pattern II. We reported a correlation rate of 84,8% between the lesion's activity on MI and « pattern I » on OCT-A, and of 96,6% between absence of activity signs on MI and « pattern II » on OCT-A The mean area of inactive lesions was slightly larger than that of active lesions with respective values of 3.86 mm² and 2.92 mm².

Conclusion

OCT-A is a non-invasive, safe, and reproducible retinal imaging technique with a high sensitivity of detection of MNV in AMD. It provides useful qualitative and quantitative data. The involvement of OCT-A in the treatment decision for MNV in AMD is linked to identifying the "pattern" of the lesion reflecting its active or inactive status.

Sensitivity and specificity of optical coherence tomography angiography in the diagnosis of active choroidal neovascularization: a systematic review and meta-analysis

PURPOSE

This meta-analysis was performed to evaluate the diagnostic value of optical coherence tomography angiography (OCTA) for active choroidal neovascularization (CNV) of all types and etiologies.

METHODS

We searched the Web of Science, PubMed, Cochrane Library, Medline, and Embase databases for all interrelated published studies from inception to August 2020. Meta-disc and STATA were used for the data analyses. We measured the diagnostic value by assessing the pooled diagnostic sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the summary receiver operating characteristic curve (sROC AUC). Sources of heterogeneity were also analyzed.

RESULTS

Nine studies involving 785 eyes were included in the meta-analysis. The pooled sensitivity was 0.83 (95% confidence interval [CI], 0.75-0.88), specificity was 0.89 (95% CI, 0.79-0.94), PLR was 7.4 (95% CI, 3.8-14.6), NLR was 0.20 (95% CI, 0.13-0.29), and DOR was 38 (95% CI, 16-91). The sROC AUC was 0.91 (95% CI, 0.89-0.94). With respect to heterogeneity, the sensitivity of the fluorescein angiography (FA) reference standard group (0.71 [0.64-0.78]) and developed country group (0.77 [0.70-0.84]) was both lower than the sensitivity of the FA combined with optical coherence tomography (OCT) reference standard group (0.89 [0.84-0.93], P < 0.001) and developing country group (0.90 [0.85-0.95], P < 0.001).

CONCLUSIONS

This meta-analysis suggests that OCTA is a non-invasive, convenient diagnostic method for active CNV and has high diagnostic value. Moreover, the accuracy of the diagnostic accuracy is independent of the types of device, algorithms, and the etiology of CNV.

Age-Related Macular Degeneration: Role of Oxidative Stress and Blood Vessels

Age-related macular degeneration (AMD) is a common irreversible ocular disease characterized by vision impairment among older people. Many risk factors are related to AMD and interact with each other in its pathogenesis. Notably, oxidative stress and choroidal vascular dysfunction were suggested to be critically involved in AMD pathogenesis. In this review, we give an overview on the factors contributing to the pathophysiology of this multifactorial disease and discuss the role of reactive oxygen species and vascular function in more detail. Moreover, we give an overview on therapeutic strategies for patients suffering from AMD.

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.

Incomplete response to Anti-VEGF therapy in neovascular AMD: Exploring disease mechanisms and therapeutic opportunities

Intravitreal anti-vascular endothelial growth factor (VEGF) drugs have revolutionized the treatment of neovascular age-related macular degeneration (NVAMD). However, many patients suffer from incomplete response to anti-VEGF therapy (IRT), which is defined as (1) persistent (plasma) fluid exudation; (2) unresolved or new hemorrhage; (3) progressive lesion fibrosis; and/or (4) suboptimal vision recovery. The first three of these collectively comprise the problem of persistent disease activity (PDA) in spite of anti-VEGF therapy. Meanwhile, the problem of suboptimal vision recovery (SVR) is defined as a failure to achieve excellent functional visual acuity of 20/40 or better in spite of sufficient anti-VEGF treatment. Thus, incomplete response to anti-VEGF therapy, and specifically PDA and SVR, represent significant clinical unmet needs. In this review, we will explore PDA and SVR in NVAMD, characterizing the clinical manifestations and exploring the pathobiology of each. We will demonstrate that PDA occurs most frequently in NVAMD patients who develop high-flow CNV lesions with arteriolarization, in contrast to patients with capillary CNV who are highly responsive to anti-VEGF therapy. We will review investigations of experimental CNV and demonstrate that both types of CNV can be modeled in mice. We will present and consider a provocative hypothesis: formation of arteriolar CNV occurs via a distinct pathobiology, termed neovascular remodeling (NVR), wherein blood-derived macrophages infiltrate the incipient CNV lesion, recruit bone marrow-derived mesenchymal precursor cells (MPCs) from the circulation, and activate MPCs to become vascular smooth muscle cells (VSMCs) and myofibroblasts, driving the development of high-flow CNV with arteriolarization and perivascular fibrosis. In considering SVR, we will discuss the concept that limited or poor vision in spite of anti-VEGF may not be caused simply by photoreceptor degeneration but instead may be associated with photoreceptor synaptic dysfunction in the neurosensory retina overlying CNV, triggered by infiltrating blood-derived macrophages and mediated by Müller cell activation Finally, for each of PDA and SVR, we will discuss current approaches to disease management and treatment and consider novel avenues for potential future therapies.

Imaging of Therapeutic Effects of Anti-Vascular Endothelial Growth Factor Inhibitors by Optical Coherence Tomography Angiography in a Rat Model

Purpose

The aim of the study was to investigate optical coherence tomography angiography (OCTA) as a high-resolution in vivo imaging modality for monitoring therapeutic response to different vascular endothelial growth factor inhibitors in the rat model of laser-induced choroidal neovascularization (CNV). Further, OCTA findings were compared with fluorescein angiography (FA) and fluorescence microscopy.

Methods

Laser treatment at day (D)0 was followed by intravitreal injection of aflibercept, AF564, and NaCl in dark agouti rats. Imaging with OCTA and FA was performed at D2, D7, D14, and D21. OCTA was compared to FA as well as confocal imaged flat mounts and analysis included quantification of CNV area, pixel intensity, vessel density, and number of vessel junctions.

Results

Within laser lesions, neovascularization were visible especially in deeper retinal layers on OCTA, but not on FA images. Using OCTA, mean CNV area (D21) at the level of the outer nuclear layer (ONL) was 0.017 mm² following aflibercept administration, 0.016 mm² following AF564 and 0.026 mm² following NaCl injection (P = 0.04 and P = 0.03). Similar differences between treatment groups were determined by FA and histology, although the overall CNV area was always larger on FA due to dye leakage (P ≤ 0.0001, all layers).

Conclusions

Compared to FA, OCTA imaging allows for a more precise and quantitative analysis of new blood vessel formation and therapeutic response to vascular endothelial growth factor (VEGF)-inhibitors, whereas it does not permit assessment of leakage.

Translational Relevance

These findings suggest that OCTA may be particularly useful for the investigation of new treatment targets in the animal model.