CHARACTERIZATION AND DIFFERENTIATION OF POLYPOIDAL CHOROIDAL VASCULOPATHY USING SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

Segmentation of retinal microaneurysms in fluorescein fundus angiography images by a novel three-step model

Introduction

Microaneurysms serve as early signs of diabetic retinopathy, and their accurate detection is critical for effective treatment. Due to their low contrast and similarity to retinal vessels, distinguishing microaneurysms from background noise and retinal vessels in fluorescein fundus angiography (FFA) images poses a significant challenge.

Methods

We present a model for automatic detection of microaneurysms. FFA images were pre-processed using Top-hat transformation, Gray-stretching, and Gaussian filter techniques to eliminate noise. The candidate microaneurysms were coarsely segmented using an improved matched filter algorithm. Real microaneurysms were segmented by a morphological strategy. To evaluate the segmentation performance, our proposed model was compared against other models, including Otsu's method, Region Growing, Global Threshold, Matched Filter, Fuzzy c-means, and K-means, using both self-constructed and publicly available datasets. Performance metrics such as accuracy, sensitivity, specificity, positive predictive value, and intersection-over-union were calculated.

Results

The proposed model outperforms other models in terms of accuracy, sensitivity, specificity, positive predictive value, and intersection-over-union. The segmentation results obtained with our model closely align with benchmark standard. Our model demonstrates significant advantages for microaneurysm segmentation in FFA images and holds promise for clinical application in the diagnosis of diabetic retinopathy.

Conclusion

The proposed model offers a robust and accurate approach to microaneurysm detection, outperforming existing methods and demonstrating potential for clinical application in the effective treatment of diabetic retinopathy.

Predicting treatment outcomes of intravitreal brolucizumab for polypoidal choroidal vasculopathy through noninvasive assessment of polypoidal lesion blood flow with optical coherence tomography angiography

We investigated the assessment of blood flow within polypoidal lesions using optical coherence tomography angiography (OCTA) to determine intravitreal brolucizumab (IVBr) efficacy for treating polypoidal choroidal vasculopathy (PCV). We retrospectively studied 46 eyes with PCV that completed 1-year IVBr treatment. Blood flow signals within polypoidal lesions were evaluated using OCTA after loading-phase treatment, and 1-year outcomes were compared between eyes in which blood flow signals disappeared versus persisting. After loading-phase treatment, blood flow signals within polypoidal lesions disappeared in 31 eyes and persisted in 15. In the former group, visual acuity improved significantly throughout the year (P < 0.01), while in the latter there was no significant difference between baseline and after 1 year. The total number of injections was significantly lower with than without disappearance of blood flow signals (6.0 vs. 6.9, P < 0.01). The intended injection interval at the last visit was significantly longer in the former than in the latter group (15.7 weeks vs. 12.5 weeks, P < 0.01). These results indicate that PCV cases showing disappearance of blood flow signals within polypoidal lesions by OCTA after loading-phase treatment had favorable 1-year outcomes of IVBr. Therefore, evaluating blood flow within polypoidal lesions by OCTA may allow noninvasive prediction of PCV treatment outcomes.

RISK OF EXUDATION IN EYES WITH NONEXUDATIVE POLYPOIDAL CHOROIDAL VASCULOPATHY

PURPOSE

To investigate the characteristics and natural history of treatment-naive nonexudative polypoidal choroidal vasculopathy (PCV) and to determine biomarkers predicting exudative conversion.

METHODS

Patients diagnosed with nonexudative PCV based on indocyanine green angiography and optical coherence tomography were included. Incidence of exudative conversion in nonexudative PCV patients and cumulative estimates for overall risk were assessed. Indocyanine green angiography and optical coherence tomography imaging-based features were analyzed to identify risk factors for exudative conversion.

RESULTS

The study included 42 eyes of 40 patients with nonexudative PCV. The mean follow-up duration was 54.3 ± 35.5 months. Of the 42 eyes with nonexudative PCV, exudative conversion developed in 23 eyes (54.8%) after 42.2 ± 28.3 months (range, 8-103 months). Kaplan-Meier analysis showed that the exudation-free survival at 5 years after baseline was estimated to be 53.6%. Multivariate regression analysis showed that sequentially increased protrusion of retinal pigment epithelium in the polyp area was a significant risk factor for exudation in nonexudative PCV (odds ratio = 10.16; 95% CI 1.78-57.81; P = 0.01).

CONCLUSION

Exudative conversion has been noted in nearly half of the nonexudative PCV cases in 5 years. The progressive protrusion of polypoidal lesions on optical coherence tomography examination may be a significant biomarker for predicting the near-term onset of exudation.

Factors Influencing Visual Acuity in Patients with Active Subfoveal Circumscribed Polypoidal Choroidal Vasculopathy and Changes in Imaging Parameters

We performed a retrospective, observational study of 51 eyes in 51 treatment-naïve patients with polypoidal choroidal vasculopathy (PCV), whose lesion ranged within the 6 × 6 mm scope of optical coherence tomography angiography (OCTA). The patients were divided into an ill-defined group and a well-defined group based on the pattern of branching vascular network (BVN) on OCTA. BVN morphology was not related to baseline best-corrected visual acuity (BCVA). However, the BCVA in the ill-defined BVN group (-0.18 [interquartile range: -0.40 to 0.00]) was significantly improved after anti-vascular endothelial growth factor (VEGF) injections, compared with that (0.00 [interquartile range: -0.18 to 0.00]) in the well-defined group (z = 2.143, p = 0.032). Multiple logistic regression analysis showed that male sex, fewer injections, and the presence of polypoidal lesions on OCTA images at baseline predicted a poor prognosis in patients with polypoidal lesions on OCTA images after anti-VEGF therapy (all p < 0.05). Finally, BCVA at baseline and the number of injections were protective factors for BCVA after anti-VEGF therapy (all p < 0.05). In contrast, a history of hypertension and macular edema at baseline were risk factors for BCVA after anti-VEGF injections (all p < 0.05). Our results revealed the visual and morphological prognosis of patients with active subfoveal circumscribed PCV after anti-VEGF therapy.

Recent Advances in Imaging Polypoidal Choroidal Vasculopathy with Swept-Source Optical Coherence Tomography Angiography

The gold standard for polypoidal choroidal vasculopathy (PCV) diagnosis is indocyanine green angiography (ICGA), but optical coherence tomography angiography (OCTA) has shown promise for PCV imaging in recent years. However, earlier generations of OCTA technology lacked the diagnostic efficacy to replace ICGA. Swept-source optical coherence tomography angiography (SS-OCTA), the latest generation of OCTA technology, has significantly improved penetrating ability, scanning speed, scanning range, and overall image quality compared with earlier generations of OCTA. SS-OCTA reveals a "tangled vasculature" pattern of polypoidal lesions (PLs), providing evidence that they are neovascular rather than aneurysmal structures. New choroidal biomarkers, such as the choriocapillaris flow void (FV), have been identified to explain the development of PCV lesions. Although no direct comparison between SS-OCTA and previous OCTA generations in terms of diagnostic capability has been performed, SS-OCTA has shown several advantages in differential diagnosis and monitoring early reactivation for PCV. These improvements make SS-OCTA a valuable tool for PCV diagnosis and follow-up, and it may become more important for this disease in the future. This review summarized recent advances in PCV morphology and structure, as well as the possible pathogenesis based on SS-OCTA findings. The value of SS-OCTA for PCV management is discussed, along with remaining issues, to provide an updated understanding of PCV and OCTA-guided management.

New Concepts for the Diagnosis of Polypoidal Choroidal Vasculopathy

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular age-related macular degeneration (nAMD) that is characterized by a branching neovascular network and polypoidal lesions. It is important to differentiate PCV from typical nAMD as there are differences in treatment response between subtypes. Indocyanine green angiography (ICGA) is the gold standard for diagnosing PCV; however, ICGA is an invasive detection method and impractical for extensive use for regular long-term monitoring. In addition, access to ICGA may be limited in some settings. The purpose of this review is to summarize the utilization of multimodal imaging modalities (color fundus photography, optical coherence tomography (OCT), OCT angiography (OCTA), and fundus autofluorescence (FAF)) in differentiating PCV from typical nAMD and predicting disease activity and prognosis. In particular, OCT shows tremendous potential in diagnosing PCV. Characteristics such as subretinal pigment epithelium (RPE) ring-like lesion, en face OCT-complex RPE elevation, and sharp-peaked pigment epithelial detachment provide high sensitivity and specificity for differentiating PCV from nAMD. With the use of more practical, non-ICGA imaging modalities, the diagnosis of PCV can be more easily made and treatment tailored as necessary for optimal outcomes.

Recent Advances in Clinical Applications of Imaging in Retinal Diseases

Many diseases that cause visual impairment, as well as systemic conditions, manifest in the posterior segment of the eye. With the advent of high-speed, high-resolution, reliable, and noninvasive imaging techniques, ophthalmologists are becoming more dependent on ocular imaging for disease diagnosis, classification, and management in clinical practice. There are rapid advances on the indications of multimodal retinal imaging techniques, including the application of ultra-widefield fundus angiography, fundus autofluorescence, optical coherence tomography, as well as optical coherence tomography angiography. This review summarizes and highlights the clinical applications, latest indications, and interpretations of multimodal imaging in age-related macular degeneration, polypoidal choroidal vasculopathy, diabetic macular edema, central serous chorioretinopathy, diabetic retinopathy, retinal vein occlusion, and uveitis.

Different Morphology of Branching Neovascular Network in Polypoidal Choroidal Vasculopathy: A Swept-Source Optical Coherence Tomography Angiography Study

Purpose: To evaluate the classification system of branching neovascular network (BNN) morphology in polypoidal choroidal vasculopathy (PCV) patients based on swept-source optical coherence tomography (SS-OCT) and swept-source optical coherence tomography angiography (SS-OCTA), and analyze the morphological features in each group as potential prognostic features. Methods: A total of 32 PCV eyes were included in this retrospective study. SS-OCT and SS-OCTA images of 6 mm × 6 mm centered on the foveal of each eye were analyzed. PCV cases were classified into three types ("trunk", "glomeruli", and "stick" type) based on the morphological features of BNN. OCT and OCTA features were compared among the three groups. The correlation of OCT/OCTA features with visual acuity at 12 months after anti-VEGF treatment was also analyzed. Results: Type 1 group had the largest BNN area and the largest numbers of polypoidal lesions. Type 2 group has the largest pigment epithelial detachment (PED) area, PED volume, subretinal fluid (SRF) area, and SRF volume. Type 3 group had better baseline BCVA, the smallest BNN area, the smallest PED size, and the smallest SRF size. Type 1 was also featured by a clear break on Bruch's membrane which corresponded to the origin of neovascular tissue. BCVA at 12 months was not significantly different among groups. Baseline BCVA and baseline central macular thickness were correlated with the final BCVA. Conclusions: The current classification system based on BNN morphology on SS-OCTA was highly applicable and revealed distinct characteristics in each group. The BNN type was not correlated with BCVA at 12 months after treatment.

Polypoidal Choroidal Vasculopathy: An Update on Diagnosis and Treatment

Polypoidal choroidal vasculopathy (PCV) is a vascular disease of the choroid that leads to hemorrhagic and exudative macular degeneration. It may cause significant vision loss and thus affect the quality-of-life and psychological well-being. Non-invasive, non-ICGA-based OCT criteria have shown reliable results to plan adjunct photodynamic therapy (PDT) treatment, with the complete and consistent coverage of polypoidal lesions (PL) and branching neovascular network (BNN). The safety and efficacy of anti-vascular endothelial growth factor (anti-VEGF) monotherapy and its combination with verteporfin PDT have been established. However, treatment is still challenging due to frequent follow-ups, non-availability of PDT, and need for multiple anti-VEGF injection visits that increase the treatment burden and lead to patients being lost to follow-up. Effective treatments that prolong intervals between injections while maintaining vision and anatomical gains remain a critical unmet need. Longer acting molecules, like brolucizumab, have shown non-inferiority in BCVA gains and superior anatomical outcomes compared to other anti-VEGF agents. Newer therapies in the pipeline to enhance the efficacy and longevity of treatment include Faricimab and a port delivery system (PDS). This review summarizes the most recent diagnostic and treatment approaches in PCV to offer better treatment avenues.

Small dome-shaped pigment epithelium detachment in polypoidal choroidal vasculopathy: an under-recognized sign of polypoidal lesions on optical coherence tomography?

PURPOSE

To evaluate the diagnostic accuracy of spectral-domain optical coherence tomography (SD-OCT) and swept-source optical coherence tomographic angiography (SS-OCTA) to identify polypoidal lesions in serous or serosanguinous maculopathy.

MATERIALS AND METHODS

A retrospective review of patients presenting pigment epithelial detachments (PEDs) with the diagnosis of polypoidal choroidal vasculopathy (PCV), neovascular age-related macular degeneration (nAMD), and central serous chorioretinopathy (CSC), all of which underwent SD-OCT, SS-OCTA, and indocyanine green angiography (ICGA). Typical features of polypoidal lesions on SD-OCT included sharply peaked PED, notched PED, and hyperreflective ring underneath PED. SS-OCTA feature was vascularized PEDs on cross-sectional images corresponding to cluster-like structures on en face images. The parameters of PEDs were measured for analysis.

RESULTS

Of 72 eyes, 30 had PCV, 22 had nAMD, and 20 had CSC. A total of 128 localized PEDs were detected on SD-OCT. Typical features on SD-OCT had a high specificity (94.0%) but a limited sensitivity (73.8%). SS-OCTA features provided a higher sensitivity (96.7%). PEDs of the polypoidal lesions unrecognized by SD-OCT were dome-shaped, with smaller ratio of height to base diameter and less area, and almost had heterogeneous internal reflectivity and a connected double-layer sign. Some lesions misidentified by SS-OCTA developed into ICGA-proven polypoidal lesions at follow-up visits.

CONCLUSION

A small dome-shaped PED with heterogeneous internal reflectivity and a connected double-layer sign on SD-OCT may suggest a polypoidal lesion of PCV. SS-OCTA may be a helpful tool to investigate preclinical PCV and observe the formation of polypoidal lesions.

Evolving treatment paradigms for PCV

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular AMD (nAMD) that accounts for a significant proportion of nAMD cases worldwide, and particularly in Asia. Contemporary PCV treatment strategies have closely followed those used in typical nAMD, though there are significant gaps in knowledge on PCV management and it remains unclear if these strategies are appropriate. Current clinical trial data suggest intravitreal anti-vascular endothelial growth factor (VEGF) therapy alone or in combination with photodynamic therapy is effective in managing haemorrhage and exudation in PCV, although the optimal treatment interval, including as-needed and treat-and-extend approaches, is unclear. Newer imaging modalities, including OCT angiography and high-resolution spectral domain OCT have enabled characterisation of unique PCV biomarkers that may provide guidance on how and when treatment and re-treatment should be initiated. Treatment burden for PCV is a major focus of future therapeutic research and several newly developed anti-VEGF agents, including brolucizumab, faricimab, and new modes of drug delivery like the port delivery system, offer hope for dramatically reduced treatment burden for PCV patients. Beyond anti-VEGF therapy, recent developments in our understanding of PCV pathophysiology, in particular the role of choroidal anatomy and lipid mediators in PCV pathogenesis, offer new treatment avenues that may become clinically relevant in the future. This article explores the current management of PCV and more recent approaches to PCV treatment based on an improved understanding of this unique disease process.

Polypoidal Choroidal Vasculopathy Diagnosis and Neovascular Activity Evaluation Using Optical Coherence Tomography Angiography

Purpose

To examine choroidal neovascularization (CNV) characteristics in patients with exudative age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV), using swept-source optical coherence tomography angiography (SS-OCTA), and investigate agreement with OCT B-scan, fundus fluorescein angiography (FFA), and indocyanine green angiography (ICGA) by two different examiners.

Methods

This is a retrospective multicentric study that involved patients with a history of AMD and PCV. Examiner A, who had access to OCTA, B-scan OCT, FFA, and ICGA imaging, had to differentiate between AMD and PCV, study the activity of AMD using Coscas' criteria (active vs. quiescent), and categorize PCV subtypes, while examiner B had only access to OCTA. Then, the diagnostic concordance was assessed between both examiners.

Results

A total of 27 patients (11 females (40.7%) and 16 males (59.3%), P = 0.231) were included in the analysis. Among those, 13 patients presented with neovascular AMD and 14 patients with PCV. There were 92.3% of correct answers regarding appropriate diagnosis and lesion characterization among AMD patients, against 61.5% of correct answers among PCV patients. The overall interrater reliability agreement between examiners, using Cohen's kappa coefficient (κ) was 0.70 (0.5082-0.8916). Disagreement was found with one active AMD misdiagnosed as inactive AMD, three inactive PCV misdiagnosed as inactive AMD, and one inactive PCV misdiagnosed as active AMD.

Conclusion

SS-OCTA alone remains limited in some specific phenotypes of PCV, which suggests the ongoing role of B-scan OCT associated with FFA and ICGA in the diagnosis of these conditions.

Appearance of Tumor Vessels in Patients With Choroidal Osteoma Using Swept-Source Optical Coherence Tomographic Angiography

Objective

To report the morphologic characteristics of tumor-related vasculatures and their association with secondary choroidal neovascularization (CNV), subretinal fluid (SRF), choroidal thickness, retinal pigment epithelium (RPE) alterations, subretinal hemorrhage, and tumor decalcification in eyes with choroidal osteoma (CO), using swept-source optical coherence tomographic angiography (SS-OCTA).

Design

Cross-sectional observational study.

Participants

We included 26 patients recruited from Beijing Tongren Hospital with a diagnosis of CO, based on the presence of yellow-orange mass deep to the RPE under indirect ophthalmoscopy and occupying the choroid with well-defined margins and bone density on ultrasonography or computed tomography and focal hyperfluorescent spots with no homogeneous pattern on fluorescein angiography/indocyanine green angiography (FA/ICGA). Data were collected from April 1, 2020, to April 1, 2021, and analyzed from April 30 through May 30, 2021.

Methods

Applying SS-OCTA systems operating at 1,050-nm wavelengths, eyes with CO were imaged.

Main Outcome and Measures

Tumor-related vasculature in eyes with CO was characterized using multimodal imaging that included fundus photography, FA/ICGA, SS-OCT, and SS-OCTA, and the images were anatomically aligned. CO thickness was manually measured as the distance between the upper boundary of the tumor and the underlying sclerochoroidal interface on the SS-OCT images. Subfoveal choroidal thickness was manually measured as the distance between the Bruch membrane and the sclerochoroidal interface on the SS-OCT images.

Results

Of the 26 Asian patients, 16 (62%) were women and 10 (38%) were men. The mean age was 26.8 years (median, 23; range, 8–45 years), and the mean best corrected visual acuity (BCVA) was 20/40. Thirty-three eyes underwent imaging and were diagnosed with CO. Indocyanine green angiography identified inhomogeneous hyperfluorescence due to tumor-related vasculature, and all corresponded to the structures that appeared as sea-fan vascular networks (SFVNs) combined with clusters of tangled vessels on SS-OCTA images. SFVNs were detected on SS-OCTA imaging in all eyes (100%), terminal tangled vascular structures in 32 of 33 eyes (97%), but not identified on ICGA. Of the 33 tangled vascular structures, 32 (97%) were located at the edge of or inside the tumor, and only 1 (3%) was associated with type 2 neovascularization. In addition, SS-OCT revealed SRF in 33 eyes (100%), 33 (100%) were located at the edge of CO, and only 1 was underlying macular. SRF with retinal edema was seen in 30 of 32 eyes (94%).

Conclusions

In eyes with CO undergoing SS-OCTA imaging, tumor-related vasculature appears as SFVNs combined with tangled vascular structures or few type 2 neovascularization. The identification of actual tumor vasculature in patients with CO as SFVNs with inner or terminal vascular tangles rather than previously described CNV may help facilitate understanding of their pathogenesis, tumor control, and response to treatment.

Multicentre, randomised clinical trial comparing intravitreal aflibercept monotherapy versus aflibercept combined with reduced-fluence photodynamic therapy (RF-PDT) for the treatment of polypoidal choroidal vasculopathy

PURPOSE

To compare the efficacy and safety of intravitreal aflibercept (IVA) monotherapy versus aflibercept combined with reduced-fluence photodynamic therapy (RF-PDT) (IVA+RF-PDT) for the treatment of polypoidal choroidal vasculopathy (PCV).

METHODS AND ANALYSIS

Multicentred, double-masked, randomised controlled trial to compare the two treatment modalities. The primary outcome of the study is to compare the 52-week visual outcome of IVA versus IVA+RF PDT. One hundred and sixty treatment-naïve patients with macular PCV confirmed on indocyanine green angiography will be recruited from three centres in Singapore. Eligible patients will be randomised (1:1 ratio) into one of the following groups: IVA monotherapy group-aflibercept monotherapy with sham photodynamic therapy (n=80); combination group-aflibercept with RF-PDT (n=80). Following baseline visit, all patients will be monitored at 4 weekly intervals during which disease activity will be assessed based on best-corrected visual acuity (BCVA), ophthalmic examination findings, optical coherence tomography (OCT) and angiography where indicated. Eyes that meet protocol-specified retreatment criteria will receive IVA and sham/RF-PDT according to their randomisation group. Primary endpoint will be assessed as change in BCVA at week 52 from baseline. Secondary endpoints will include anatomical changes based on OCT and dye angiography as well as safety assessment. Additionally, we will be collecting optical coherence tomography angiography data prospectively for exploratory analysis.

ETHICS AND DISSEMINATION

This study will be conducted in accordance with the ethical principles that have their origin in the Declaration of Helsinki and that are consistent with the ICH E6 guidelines of Good Clinical Practice and the applicable regulatory requirements. Approval from the SingHealth Centralised Institutional Review Board has been sought prior to commencement of the study.

TRIAL REGISTRATION NUMBER

NCT03941587.

Non-ICGA treatment criteria for Suboptimal Anti-VEGF Response for Polypoidal Choroidal Vasculopathy: APOIS PCV Workgroup Report 2

PURPOSE

To develop and validate OCT and color fundus photography (CFP) criteria in differentiating polypoidal choroidal vasculopathy (PCV) from typical neovascular age-related macular degeneration (nAMD) in eyes with suboptimal response to anti-vascular endothelial growth factor (VEGF) monotherapy and to determine whether OCT alone can be used to guide photodynamic therapy (PDT) treatment.

DESIGN

Clinical study evaluating diagnostic accuracy.

PARTICIPANTS

Patients with nAMD who received 3-month anti-VEGF monotherapy but had persistent activity defined as subretinal fluid or intraretinal fluid at month 3 assessments.

METHODS

In phase 1, international retina experts evaluated OCT and CFP of eyes with nAMD to identify the presence or absence of features due to PCV. The performance of individual and combinations of these features were compared with ICGA. In phase 2, these criteria were applied to an independent image set to assess generalizability. In a separate exercise, retinal experts drew proposed PDT treatment spots using only OCT and near-infrared (NIR) images in eyes with PCV and persistent activity. The location and size of proposed spot were compared with ICGA to determine the extent of coverage of polypoidal lesions (PLs) and branching neovascular network (BNN).

MAIN OUTCOME MEASURES

Sensitivity and specificity of CFP and OCT criteria to differentiate PCV from nAMD and accuracy of coverage of OCT-guided PDT compared with ICGA.

RESULTS

In eyes with persistent activity, the combination of 3 non-ICGA-based criteria (sharp-peaked pigment epithelial detachment [PED], subretinal pigment epithelium [RPE] ring-like lesion, and orange nodule) to detect PCV showed good agreement compared with ICGA, with an area under the receiver operating characteristic curve of 0.85. Validation using both an independent image set and assessors achieved an accuracy of 0.77. Compared with ICGA, the OCT-guided PDT treatment spot covered 100% of PL and 90% of the BNN.

CONCLUSIONS

In nAMD eyes with persistent activity, OCT and CFP can differentiate PCV from typical nAMD, which may allow the option of adjunct PDT treatment. Furthermore, OCT alone can be used to plan adjunct PDT treatment without the need for ICGA, with consistent and complete coverage of PL.

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.

Contribution of OCT angiography in angioid streaks

PURPOSE

To study the appearance of angioid streaks (AS) in swept source optical coherence tomography angiography.

METHODS

Retrospective observational study of 16 patients (31 eyes) with various stages of AS. All included patients underwent complete ophthalmologic examinations including best-corrected visual acuity (BCVA), slit-lamp examination, indirect ophthalmoscopy and fundus photography. Swept source optical coherence tomography (SS-OCT), OCT angiography (OCT-A) and fluorescein angiography were also performed.

RESULTS

En face OCT detected hyper-reflective points in 65% of cases, with a choriocapillaris (CC) shadow on the corresponding OCT-A. Diffuse CC rarefaction was detected in 94%. In eyes without neovascular complications, streaks were visible as a hyposignal in the outer retina. An irregular vascular network (IVN) was detected in 80% of eyes. It filled the spaces between the AS and corresponded to flat elevation of the retinal pigmentary epithelium. Twenty-four eyes had choroidal neovascularization (CNV). CNV was type 1 in 8%, type 2 in 43%, mixed in 20% and unclassified in 29% because of a large scar. We found multiple sites of CNV in 8% of cases. CNV shape was tangled in 66% and in 2 eyes with newly diagnosed CNV. OCT-A showed a perilesional halo around new CNV. The morphology and configuration of neovascular network follow the IVN and the path of the AS and arises in proximity to sites of BM disruption.

CONCLUSION

OCT-A allows early detection and monitoring of AS and their neovascular complications. It shows CC rarefaction, IVN and a predominantly tangled shape of CNV. However, there are some limitations associated with difficulty in characterizing signs of CNV activity.

Clinical characteristics of super stable polypoidal choroidal vasculopathy after initial remission with anti-VEGF monotherapy

PURPOSE

To define a "super stable" subset of polypoidal choroidal vasculopathy (PCV) patients that have a long period of remission following anti-vascular endothelial growth factor (VEGF) therapy.

METHODS

Twenty-one eyes that showed no recurrence for over 18 months following anti-VEGF monotherapy were included in the "super stable PCV group" and compared with 37 eyes with recurring disease. Patient demographics, visual acuity, and imaging data from optical coherence tomography (OCT) and fluorescein angiography/indocyanine green angiography were compared between the two groups at baseline and at 3 months after treatment initiation.

RESULTS

The super stable group maintained remission for a mean duration of 31.0 months following a mean of 4.1 anti-VEGF injections. The super stable group was younger at baseline (64.6 ± 8.8 vs. 71.4 ± 7.9 years, P < 0.05) with a higher ratio of females (52.4% vs. 24.3%, P < 0.05) compared with the control group. The super stable group had a higher percentage of eyes with a single polyp, as opposed to multiple polyps (66.7% vs. 32.4%, P < 0.05), and the diameter of the largest polyp was smaller (328.4 ± 98.2 vs. 398.3 ± 112.2 μm, P < 0.05). Baseline choroidal thickness was greater in the super stable group (357 ± 102.7 vs. 293.2 ± 94.6 μm, P < 0.05). At 3 months after treatment, OCT features including central retinal thickness, pigment epithelial detachment (PED) size, and presence of subretinal fluid showed superior response in the super stable group. The reduction in PED height was almost 3 times as large in the super stable group (- 250.1 ± 228.5 μm vs. - 84.4 ± 221.1 μm, P < 0.05). Binary logistic regression further showed that factors such as age, polyp configuration, PED diameter at 3 months, and change in PED height at 3 months were associated with super stable remission.

CONCLUSION

Identifying super stable PCV patients can prevent overtreatment and lessen treatment burden.

Quantitative Analysis of the Choriocapillaris in Uveitis Using En Face Swept-Source Optical Coherence Tomography Angiography

PURPOSE

To perform a quantitative analysis of choriocapillaris (CC) flow deficits (FDs) in patients with uveitis.

DESIGN

Retrospective cross-sectional study.

METHODS

Swept-source optical coherence tomography based angiography (SS-OCTA) macular volume scans (3 × 3 mm and 6 × 6 mm) were obtained using the Plex Elite 9000. En face CC images were generated and analyzed using an automated FD identification algorithm. Three quantitative metrics were determined for each eye: FD number (FDN), mean FD size (MFDS), and FD density (FDD). Quantitative metrics were compared between uveitis and control eyes. The uveitis cohort was further subdivided by the presence or absence of choroidal involvement, and quantitative metrics were compared between subgroups and normal control subjects.

RESULTS

A total of 38 eyes from 38 control subjects and 73 eyes from 73 uveitis subjects were included in this study. Eyes with uveitis have significantly larger CC MFDS (3- × 3-mm scans; P < .0001; 6- × 6-mm scans; P < .0001) and higher FDD (P = .0002; P = .0076, respectively) compared to control eyes. Additional analysis determined that these differences were due to the choroidal disease subgroup, which demonstrates significantly larger MFDS (3 × 3 = 1,108 μm²; 6 × 6 = 1,104 μm²) compared to both normal control eyes (752 μm²; P < .0001; 802 μm²; P < .0001, respectively) and uveitis patients without choroidal involvement (785 μm²; P < .0001; 821 μm²; P < .0001, respectively). No significant differences were found between the quantitative metrics of control subjects and patients without choroidal involvement.

CONCLUSIONS

Automated quantification of CC can identify pathological FDs and provide quantitative metrics describing such lesions in patients with uveitis. Posterior uveitis patients have significantly larger CC FDs than patients with other forms of uveitis.

A Comparison Study of Polypoidal Choroidal Vasculopathy Imaged with Indocyanine Green Angiography and Swept-Source Optical Coherence Tomography Angiography

PURPOSE

Indocyanine green angiography (ICGA) was compared with swept-source optical coherence tomography angiography (SS-OCTA) for the detection of polypoidal choroidal vasculopathy (PCV).

DESIGN

Retrospective, cross-sectional.

METHODS

Patients with treatment-naïve PCV based on ICGA imaging underwent same-day SS-OCTA imaging at Kyung Hee University Medical Center between April 2017 and November 2018. ICGA and SS-OCTA images were graded independently. SS-OCTA images were graded using both flow and structural information. Images were graded for the number of polypoidal lesions and the total lesion area, which included both the polypoidal lesions and the branching vascular networks (BVNs).

RESULTS

A total of 31 eyes from 30 patients were enrolled. Polypoidal lesions were identified in all eyes using both modalities, and there was agreement on the number of polypoidal lesions in 17 eyes (55%). In 12 eyes (39%), SS-OCTA graders identified a greater number of polypoidal lesions, and in 2 eyes (6%) ICGA graders identified more lesions. There was no significant difference in the lesion area measurements (standard deviation = 1.09, P = .08). The lesion with the largest difference in area measurements resulted from focal areas of atrophy, misdiagnosed as polypoidal lesions on ICGA, and a low-lying serous retinal pigment epithelial detachment erroneously identified as part of the BVN by ICGA graders. SS-OCTA imaging correctly diagnosed the focal areas of atrophy and the serous retinal pigment epitheial detachment.

CONCLUSIONS

SS-OCTA imaging was comparable to ICGA for the diagnosis of treatment-naïve PCV. However, SS-OCTA might be better than ICGA in correctly identifying both polypoidal lesions and BVNs in treatment-naïve PCV.

Polypoidal Choroidal Vasculopathy: Consensus Nomenclature and Non-Indocyanine Green Angiograph Diagnostic Criteria from the Asia-Pacific Ocular Imaging Society PCV Workgroup

PURPOSE

To develop consensus terminology in the setting of polypoidal choroidal vasculopathy (PCV) and to develop and validate a set of diagnostic criteria not requiring indocyanine green angiography (ICGA) for differentiating PCV from typical neovascular age-related macular degeneration (nAMD) based on a combination of OCT and color fundus photography findings.

DESIGN

Evaluation of diagnostic test results.

PARTICIPANTS

Panel of retina specialists.

METHODS

As part of the Asia-Pacific Ocular Imaging Society, an international group of experts surveyed and discussed the published literature regarding the current nomenclature and lesion components for PCV, and proposed an updated consensus nomenclature that reflects our latest understanding based on imaging and histologic reports. The workgroup evaluated a set of diagnostic features based on OCT images and color fundus photographs for PCV that may distinguish it from typical nAMD and assessed the performance of individual and combinations of these non-ICGA features, aiming to propose a new set of diagnostic criteria that does not require the use of ICGA. The final recommendation was validated in 80 eyes from 2 additional cohorts.

MAIN OUTCOME MEASURES

Consensus nomenclature system for PCV lesion components and non-ICGA-based criteria to differentiate PCV from typical nAMD.

RESULTS

The workgroup recommended the terms polypoidal lesion and branching neovascular network for the 2 key lesion components in PCV. For the diagnosis of PCV, the combination of 3 OCT-based major criteria (sub-retinal pigment epithelium [RPE] ring-like lesion, en face OCT complex RPE elevation, and sharp-peaked PED) achieved an area under the receiver operating characteristic curve of 0.90. Validation of this new scheme in a separate subset 80 eyes achieved an accuracy of 82%.

CONCLUSIONS

We propose updated terminology for PCV lesion components that better reflects the nature of these lesions and is based on international consensus. A set of practical diagnostic criteria applied easily to spectral-domain OCT results can be used for diagnosing PCV with high accuracy in clinical settings in which ICGA is not performed routinely.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY CHARACTERISTICS OF POLYPOIDAL CHOROIDAL VASCULOPATHY SECONDARY TO CHRONIC CENTRAL SEROUS CHORIORETINOPATHY

PURPOSE

To report diagnostic capability of optical coherence tomography angiography (OCTA) in detecting polypoidal choroidal vasculopathy and its morphologic characteristics in white patients with chronic central serous chorioretinopathy.

METHODS

Retrospective consecutive series of 20 eyes (17 consecutive patients) with a diagnosis of polypoidal choroidal vasculopathy secondary to chronic central serous chorioretinopathy based on clinical and multimodal imaging were included. All patients underwent a complete ophthalmologic examination, including best-correct visual acuity, fundus autofluorescence, fluorescein and indocyanine green angiography, spectral-domain optical coherence tomography, and OCTA.

RESULTS

In all eyes (100%), OCTA revealed the branching vascular network as a hyperflow lesion in both choriocapillaris and outer retina layers. Segmentation of the choriocapillaris in OCTA, in correspondence of the polypoidal dilation detected at indocyanine green angiography, showed a hyperflow round structure in 75% of cases and hypoflow round structure in 15%. Two of 20 eyes (10%) had no detectable polyps on OCTA.

CONCLUSION

Optical coherence tomography angiography is a noninvasive imaging modality allowing a good visualization of both branching vascular network and polyp dilations. Our findings suggest that OCTA is a useful tool in the investigation of chronic central serous chorioretinopathy complicated by polypoidal choroidal vasculopathy.

Using optical coherence tomography angiography in assessment of the anti-vascular endothelial growth factor effect for pathological vascular tissue in age-related macular degeneration and polypoidal choroidal vasculopathy

PURPOSE

Using optical coherence tomography angiography to assess and compare changes in pathological vascular tissue, including choroidal neovascularization in neovascular age-related macular degeneration and polypoidal complex in polypoidal choroidal vasculopathy, after treatment with anti-vascular endothelial growth factor.

METHODS

This is a retrospective observational case series study. Clinical data were collected, including that on the best-corrected visual acuity and images of spectrum domain optical coherence tomography and optical coherence tomography angiography of consecutive patients with macula-involved lesions, active pathological vascular tissue in neovascular age-related macular degeneration, and polypoidal complex in polypoidal choroidal vasculopathy who were treated with anti-vascular endothelial growth factor injection. The primary outcome measures were the lesion area, flow density, and flow area of the pathological vascular tissue obtained in optical coherence tomography angiography before treatment, as well as week-1 (W1) and week-5 (W5) after treatment. The secondary outcome measures were the best-corrected visual acuity and the anatomic changes in spectrum domain optical coherence tomography at the same periods.

RESULTS

A total of 86 eyes in 79 patients (mean age: 73.10 ± 10.10 (range = 50-91) years, 45 males (57%), of which two eyes were treatment-naïve) underwent one section of intravitreal treatment. Of which 44 eyes (40 patients) were diagnosed as typical neovascular age-related macular degeneration and 42 eyes (39 patients) as polypoidal choroidal vasculopathy. The sensitivity for detecting choroidal neovascularization in neovascular age-related macular degeneration and polypoidal complex in polypoidal choroidal vasculopathy was 75.00% (33/44) and 69.05% (29/42), respectively. There was no significant difference in the detection rate between neovascular age-related macular degeneration and polypoidal choroidal vasculopathy (p = 0.54). In the detectable group, there were significant decrease in lesion area and flow area in the optical coherence tomography angiography images after anti-vascular endothelial growth factor treatment in both the neovascular age-related macular degeneration group (lesion area: W1 = -26.94 ± 19.50%, W5 = -35.52 ± 30.85%, all ps < 0.001; flow area: W1 = -26.22 ± 25.23%, W5 = -32.24 ± 32.07%, all ps < 0.001) and the polypoidal choroidal vasculopathy group (lesion area: W1 = -25.19 ± 20.27%, W5 = -31.55 ± 27.04%, all ps < 0.001; flow area: W1 = -21.83 ± 26.29%, W5 = -28.31 ± 30.72%, all ps < 0.001). The central subfield retinal thickness in spectrum domain optical coherence tomography also showed similar amelioration in both groups. However, the flow density in optical coherence tomography angiography image and the visual outcome did not reveal any significant difference before or after intravitreal injections, and neither were there significant differences between the neovascular age-related macular degeneration and polypoidal choroidal vasculopathy groups. Concerning the effect on the optical coherence tomography angiography images of pathological vascular tissue, there were no statistical differences among different anti-vascular endothelial growth factor agents (i.e. aflibercept, ranibizumab, and bevacizumab).

CONCLUSION

Our study revealed that optical coherence tomography angiography can be used noninvasively and quantitatively to assess the detailed pathologic vascular structures in both neovascular age-related macular degeneration and polypoidal choroidal vasculopathy. Our study also demonstrated that anti-vascular endothelial growth factor could effectively decrease the lesion size and flow area of both the choroidal neovascularization in neovascular age-related macular degeneration cases and the polypoidal complex in polypoidal choroidal vasculopathy cases; the effects were similar in both diseases.

Appearance of Polypoidal Lesions in Patients With Polypoidal Choroidal Vasculopathy Using Swept-Source Optical Coherence Tomographic Angiography

Importance

Polypoidal choroidal vasculopathy (PCV) is a major cause of visual loss worldwide, particularly in Asia, and the appropriate understanding of the structures in PCV previously described as polypoidal lesions is important for understanding their pathogenesis, diagnosis, and prognosis.

Objective

To report the morphologic characteristics of polypoidal lesions and their association with branching vascular networks (BVNs) in eyes with PCV using swept-source optical coherence tomographic angiography (SS-OCTA).

Design, Setting, and Participants

This cross-sectional observational study included 20 participants recruited from Shanghai General Hospital with a diagnosis of PCV based on the presence of focal hyperfluorescent spots on indocyanine green angiography (ICGA). Data were collected from December 1, 2017, to September 1, 2018, and analyzed from June 1 through September 30, 2018.

Main Outcomes and Measures

Polypoidal lesions in eyes with PCV were characterized using multimodal imaging that included fundus photography, fluorescein angiography, ICGA, SS-OCT, and SS-OCTA, and the images were anatomically aligned. Subfoveal choroidal thickness was manually measured as the distance between the Bruch membrane and the sclerochoroidal interface on the SS-OCT images.

Results

Of the 20 Asian patients, 5 (25%) were women and 15 (75%) were men. The mean (SD) age was 61.1 (7.6) years, and the mean (SD) logMAR visual acuity was 0.358 (0.294) (Snellen equivalent, 20/50 [20/40]). Twenty-three eyes underwent imaging and were diagnosed with PCV. Indocyanine green angiography identified 43 polypoidal lesions, and all corresponded to the structures that appeared as clusters of tangled vessels on SS-OCTA images. In addition, SS-OCTA detected 16 tangled vascular structures not seen on ICGA. Branching vascular networks were detected on SS-OCTA imaging in all eyes, but ICGA identified BVNs in only 17 of 23 eyes (74%). Of the 43 tangled vascular structures, 40 (93%) were located at the edge of a BVN and 3 (7%) were associated with type 2 neovascularization.

Conclusions and Relevance

In eyes with PCV undergoing SS-OCTA imaging, previously described polypoidal lesions may appear as tangled vascular structures associated with BVN or type 2 neovascularization. The identification of polypoidal lesions in patients with PCV as neovascular tangles rather than actual polypoidal lesions or aneurysmal dilatations may help facilitate understanding of their pathogenesis and response to treatment.

Comparison of OCT and OCTA manifestations among untreated PCV, neovascular AMD, and CSC in Chinese population

AIM

To compare the qualitative and quantitative features among untreated polypoidal choroidal vasculopathy (PCV), neovascular age-related macular degeneration (nv-AMD) and central serous chorioretinopathy (CSC) using optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

This retrospective study included 16 eyes with thin-choroid PCV, 18 eyes with thick-choroid PCV, 16 eyes with nv-AMD and 17 eyes with CSC, respectively. The indicators were obtained by OCT and OCTA.

RESULTS

Sub-foveal choroidal thickness (SFCT) in CSC was thicker compared to other groups (all P<0.05). SFCT in nv-AMD was thicker compared to thin-choroid PCV, but thinner compared with thick-choroid PCV (both P<0.05). As the ratio of thickness of Haller's layer to thickness of SFCT, which of thin-choroid PCV was significantly higher than CSC (P<0.001). Likewise, thick-choroid PCV had significantly higher ratio than nv-AMD (P=0.016) or CSC (P<0.001). There were differences among them in pigment epithelium detachment (PED). The whole-superficial retinal vessel density (RVD), deep RVD and choroidal capillary vessel density (CCVD) in CSC were significantly higher compared to other three groups, respectively (all P<0.05). The whole CCVD in nv-AMD was higher compared to thick-choroid PCV (P=0.032). Cross-sectional local angiographic form was 87.50%, 83.33%, 0 and 35.29% in thin-choroid PCV, thick-choroid PCV, nv-AMD and CSC, respectively. Cross-sectional diffuse angiographic form was 12.50%, 16.67%, 100% and 5.88% in thin-choroid PCV, thick-choroid PCV, nv-AMD and CSC, respectively.

CONCLUSION

Combination of OCT and OCTA can effectively observe the significant alterations existed in PCV, CSC and nv-AMD, and there are distinctive differences among them. The pathogenesis is not exactly the same between PCV and nv-AMD, or PCV and CSC.

Detection Rate and Diagnostic Value of Optical Coherence Tomography Angiography in the Diagnosis of Polypoidal Choroidal Vasculopathy: A Systematic Review and Meta-Analysis

Purpose

This study aimed to evaluate the detection rate of polyps and branching vascular networks (BVNs) in polypoidal choroidal vasculopathy (PCV) by optical coherence tomography angiography (OCTA) and assess the sensitivity and specificity of OCTA in differentiating PCV from wet age-related macular degeneration (wAMD).

Materials and Methods

We searched PubMed, EMBASE, Cochrane Library, and other sources. The detection rates of polyps and BVNs in observational studies and the sensitivity and specificity of PCV diagnosis from wAMD in diagnostic studies were extracted.

Results

Twenty studies (573 eyes) were eligible. The combined detection rate of OCTA in PCV polyp lesion diagnosis was 0.67 (95% CI: 0.55–0.79), while that of BVNs was 0.86 (95% CI: 0.81–0.91). The detection rate of polyps was compared with that of BVNs in the same study, and the combined relative risk was 0.82 (95% CI: 0.72–0.92). The combined sensitivity of PCV diagnosis in wAMD patients using OCTA was 0.77 (95% CI: 0.55–0.90), combined specificity 0.84 (95% CI: 0.60–0.95), and area under the SROC curve 0.87 (95% CI: 0.84–0.90).

Conclusion

OCTA has a high PCV polyp and BVN detection rate, and the detection rate of BVNs is higher than that of the polyp. OCTA has acceptable sensitivity and specificity for diagnosing PCV from wAMD. Thus, OCTA may be helpful for clinical diagnosis of PCV.

Microvascular contributions to age-related macular degeneration (AMD): from mechanisms of choriocapillaris aging to novel interventions

Aging of the microcirculatory network plays a central role in the pathogenesis of a wide range of age-related diseases, from heart failure to Alzheimer's disease. In the eye, changes in the choroid and choroidal microcirculation (choriocapillaris) also occur with age, and these changes can play a critical role in the pathogenesis of age-related macular degeneration (AMD). In order to develop novel treatments for amelioration of choriocapillaris aging and prevention of AMD, it is essential to understand the cellular and functional changes that occur in the choroid and choriocapillaris during aging. In this review, recent advances in in vivo analysis of choroidal structure and function in AMD patients and patients at risk for AMD are discussed. The pathophysiological roles of fundamental cellular and molecular mechanisms of aging including oxidative stress, mitochondrial dysfunction, and impaired resistance to molecular stressors in the choriocapillaris are also considered in terms of their contribution to the pathogenesis of AMD. The pathogenic roles of cardiovascular risk factors that exacerbate microvascular aging processes, such as smoking, hypertension, and obesity as they relate to AMD and choroid and choriocapillaris changes in patients with these cardiovascular risk factors, are also discussed. Finally, future directions and opportunities to develop novel interventions to prevent/delay AMD by targeting fundamental cellular and molecular aging processes are presented.

Novel Findings of Polypoidal Choroidal Vasculopathy via Optical Coherence Tomography Angiography

Purpose

To introduce novel findings of polypoidal choroidal vasculopathy (PCV) via optical coherence tomography angiography (OCTA)

Methods

This study is a retrospective chart review of 16 patients (16 eyes) with PCV. OCTA (Avanti RTVue XR) findings were evaluated and selected for analysis after agreement by two retina specialists .

Results

Twenty one polyps in 16 eyes (16 patients) with PCV were included in this study. The mean patient age was 67 years (13 men and three women). The shape of polypoidal lesions on OCTA at initial were halo (five polyps), rosette (seven polyps), and vascular network (nine polyps). Eight months after anti-vascular endothelial growth factor treatment, in a total of four eyes, seven polyps could be followed up completely, the two halo type polypoidal lesions changed to rosette and vascular network type. The lesions of three rosette and two vascular network type lesions did not change in shape. In addition, the size of the polypoidal lesions (one among two halo types, two among three rosette types, and two among two vascular network types) decreased, but one halo type did not change and one rosette type increased in size on OCTA.

Conclusions

En-face OCTA enabled us to categorize novel types of PCV with polypoidal lesions.

Test performance of optical coherence tomography angiography in detecting retinal diseases: a systematic review and meta-analysis

OBJECTIVE

To investigate the diagnostic accuracy of optical coherence tomography angiography (OCTA) in detecting vascular characteristics of chorio-retinal disease.

METHODS

Evidence acquisition: We searched Web of Science, Scopus, and Medline by the citation of references and complemented these electronic searches by checking the list of references of included and review articles. Screening, selection, assessment, and extraction was performed in parallel by two authors.

RESULTS

Evidence synthesis: Systematic review and exploratory meta-analysis. The ten studies that contributed to the meta-analysis enrolled 440 eyes and allowed constructing ten two-by-two tables. The tables reported on detection of choroidal neovascularization (CNV) in eyes suffering from either age-related macular degeneration (4), central serous chorioretinopathy (2), myopia (2), foveomacular vitelliform dystrophy (1), or a mixed cohort suffering from multiple retinal diseases (1). Of the ten studies, six used a cohort and four a case-control design. We found a pooled sensitivity of 0.90 (95% confidence intervals (CIs): 0.82-0.95) and a pooled specificity of 0.97 (95% CI: 0.89-0.99). Corresponding positive and negative likelihood ratios were 32.3 (95% CI: 7.4-141.6) and 0.10 (95% CI: 0.06-0.20), respectively. No pooling was possible for retinal vascular parameters of diabetic retinopathy, polypoidal choroidal vasculopathy, or detection of CNV activity.

CONCLUSIONS

The results of highly biased and heterogeneous studies assessing the diagnostic performance of OCTA highlight the need for further analyses of methodologically sound and sufficiently sized clinical evaluations.

Characterizing Branching Vascular Network Morphology in Polypoidal Choroidal Vasculopathy by Optical Coherence Tomography Angiography

This study analyze the morphological characteristics of branching vascular networks (BVN) in polypoidal choroidal vasculopathy (PCV) using optical coherence tomography angiography (OCTA), and correlate imaging characteristics with clinical presentations. We presented a retrospective observational case series for fifty cases of PCV confirmed by indocyanine green angiography. Macular OCTA were done by the AngioVue. The PCV cases were classified by distinct morphologic patterns of BVN by two retina specialists and clinical features were analyzed. The sensitivity of polyp detection by OCTA was 86% after manual segmentation and that of BVN was 90%. Three distinct morphologic patterns of BVN were identified. (1) The “Trunk” pattern (47%) exhibited major vessel trunk with features including presence of drusens, thin choroid, and larger BVN area. (2) The “Glomeruli” pattern (33%) showed anastomotic vascular network without major trunk. (3) The “Stick” pattern (20%) had localized BVN and the thickest choroid. Subtypes 2 and 3 held higher recurrence rate. In conclusions, the precise visualization of BVN on OCTA supported that OCTA might be a noninvasive tool to study the morphology of BVN in PCV, which exhibits three different morphological types. Identifying the morphology of BVN has the potential to prognosticate outcomes in PCV patients.

Visualization of Choriocapillaris and Choroidal Vasculature in Healthy Eyes With En Face Swept-Source Optical Coherence Tomography Versus Angiography

Purpose

To compare the visualization of the choriocapillaris and deeper choroidal vessels in healthy eyes in en face swept-source optical coherence tomography (SS-OCT) versus SS-OCT angiography (SS-OCTA).

Methods

This is a cross-sectional study of consecutive eyes without chorioretinal disease. En face SS-OCT and SS-OCTA images of the choriocapillaris and choroid were assessed for visualization of the vasculature. Choroidal vessel densities (CVD) of the choriocapillaris, inner choroid, midchoroid, and outer choroid were calculated from binarized en face SS-OCT and SS-OCTA images. Paired t-tests and linear regression were used for statistical analysis.

Results

Twenty-seven eyes of 27 patients were included. There was no statistically significant difference between the CVDs of the midchoroid assessed with en face SS-OCT versus SS-OCTA (P = 0.21). However, there were statistically significant differences between the CVDs for the choriocapillaris (P < 0.001), inner choroid (P < 0.001), and outer choroid (P = 0.006). Qualitative analysis revealed incomplete visualization of vessels in the inner choroid and exaggeration of vessel lumens in the outer choroid with SS-OCTA.

Conclusions

Visualization of the choriocapillaris is superior with SS-OCTA, but it has numerous limitations that make visualization of deeper choroidal vessels less reliable when compared with en face SS-OCT. It is important to understand such limitations when using these technologies to study the choroidal vasculature in chorioretinal disease.

Translational Relevance

The presented study of optimal imaging techniques for the choroidal vessels of healthy eyes provides an important foundation for future investigations into the role of the choroidal vasculature in chorioretinal diseases.

Microperimetry and multimodal imaging in polypoidal choroidal vasculopathy

Polypoidal choroidal vasculopathy (PCV) is a degenerative macular disease. The study determined the topographical concordance in the areal extent of PCV, defined by indocyanine green angiography (ICGA), and the corresponding outcomes from spectral-domain optical coherence tomography (SD-OCT) and microperimetry, in 25 individuals (25 eyes) who had undergone 3 months of anti-vascular endothelial growth factor treatment. The differential light sensitivity within 10° eccentricity was evaluated by Pattern Deviation probability analysis. The concordances and proportional areal extents of the abnormality for ICGA, SD-OCT and microperimetry were compared. The concordance in the areal extent between all three modalities was 59%. The median concordance between ICGA and microperimetry was 60%; between ICGA and SD-OCT, 70%; and between SD-OCT and microperimetry, 72%. SD-OCT and microperimetry each identified a greater areal extent (>20%) compared to ICGA in 13 and 19 eyes, respectively. A greater areal extent (>20%) was present in 9 eyes for microperimetry compared to SD-OCT and in 5 eyes for SD-OCT compared to microperimetry. SD-OCT and microperimetry each identified a greater area of abnormality than ICGA which supports the clinical utility of SD-OCT. Strong concordance was present between SD-OCT and microperimetry; however, microperimetry identified additional areas of functional abnormality.

Incidence of Fellow Eye Involvement in Patients With Unilateral Exudative Age-Related Macular Degeneration

Importance

Since the advent of optical coherence tomography angiography (OCT-A), nonexudative neovascularization has been described in the fellow eyes of unilateral exudative age-related macular degeneration (AMD). However, there is limited literature describing the natural course and optimal management of these lesions.

Objective

To determine the incidence of fellow eye involvement in patients presenting with unilateral typical AMD or polypoidal choroidal vasculopathy and to evaluate the patterns of OCT-A changes within 6 months before the onset of exudative changes, especially focusing on nonexudative neovascularization.

Design, Setting, and Participants

Data for this study were taken from a prospective, observational cohort study involving Asian patients with exudative AMD in the Asian AMD Phenotyping Study between October 2015 and March 2016. Analyses began in June 2017. Only patients who had gradable OCT-A and indocyanine green angiography (ICGA) scans of the fellow eye at baseline and follow-up at least 6 months apart were included for the analysis. The contralateral eye was evaluated for presence of nonexudative neovascularization based on multimodal imaging, which included ICGA, spectral domain optical coherence tomography, and OCT-A.

Main Outcomes and Measures

The difference between the incidence of those with nonexudative choroidal neovascularization and those without as analyzed using log-rank test and qualitative analysis of OCT-A images.

Results

We included 95 fellow eyes of 95 patients who presented with unilateral exudative AMD with a mean (SD) age of 68.6 (8.6) years. Nonexudative neovascularization was present in 18 eyes (19%) (8 [22.9%] and 10 [19.0%] fellow eyes with typical AMD and polypoidal choroidal vasculopathy, respectively; 8 [44.4%] on OCT-A; 5 [27.8%] on ICGA; and 5 [27.8%] on both OCT-A and ICGA). Development of exudative changes was noted in 6 fellow eyes (6.3%). Four eyes developed exudation from previously noted nonexudative neovascularization, and 2 eyes arose exudative changes from de novo. The probability of developing exudation within 6 months was significantly higher in eyes with baseline nonexudative neovascularization (0.087; 95% CI, 0.0033-0.210) compared with eyes without (0.010; 95% CI, 0.0026-0.041) (P = .008). In all eyes whose OCT-A images were available immediately before the onset of exudative changes, there was an increase in the size of network vessels compared with baseline.

Conclusions and Relevance

The presence of nonexudative neovascularization may predispose to the development of exudative changes.

Clinical applications of optical coherence tomography angiography: What we have learnt in the first 3 years

A review of the literature from 2014 to 2016 was conducted, focusing on the results of optical coherence tomography angiography in different chorioretinal diseases. In only 3 years, optical coherence tomography angiography has been shown to be an effective tool for diagnosing choroidal neovascularization complicating age-related macular degeneration, pathologic myopia, and inflammatory conditions. The technique has sometimes been considered superior to conventional multimodal imaging, for example, in choroidal neovascularization associated with chronic central serous chorioretinopathy or multifocal choroiditis. In retinal vascular diseases, optical coherence tomography angiography has helped to understand the condition described as paracentral acute middle maculopathy and has been considered highly effective for the analysis of retinal vascular macular changes secondary to retinal vein occlusion or macular telangiectasia. Changes in the foveal avascular zone, also reported in diabetic maculopathy, have been shown to occur before any angiographic signs. A reduction in capillary vascular density has been reported in the fovea of eyes with malignant melanoma, but not in eyes with choroidal nevus. However, optical coherence tomography angiography is a recent technique that probably needs refinements and further studies. Nevertheless, the first 3 years of optical coherence tomography angiography use suggest its clinical relevance and useful applications in daily clinical practice.

An overview of the clinical applications of optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) has emerged as a novel, non-invasive imaging modality that allows the detailed study of flow within the vascular structures of the eye. Compared to conventional dye angiography, OCTA can produce more detailed, higher resolution images of the vasculature without the added risk of dye injection. In our review, we discuss the advantages and disadvantages of this new technology in comparison to conventional dye angiography. We provide an overview of the current OCTA technology available, compare the various commercial OCTA machines technical specifications and discuss some future software improvements. An approach to the interpretation of OCTA images by correlating images to other multimodal imaging with attention to identifying potential artefacts will be outlined and may be useful to ophthalmologists, particularly those who are currently still unfamiliar with this new technology. This review is based on a search of peer-reviewed published papers relevant to OCTA according to our current knowledge, up to January 2017, available on the PubMed database. Currently, many of the published studies have focused on OCTA imaging of the retina, in particular, the use of OCTA in the diagnosis and management of common retinal diseases such as age-related macular degeneration and retinal vascular diseases. In addition, we describe clinical applications for OCTA imaging in inflammatory diseases, optic nerve diseases and anterior segment diseases. This review is based on both the current literature and the clinical experience of our individual authors, with an emphasis on the clinical applications of this imaging technology.