A Comparison Between Optical Coherence Tomography Angiography and Fluorescein Angiography for the Imaging of Type 1 Neovascularization

Microvascular Density Analysis of Patients with Inactive Systemic Lupus Erythematosus-A Two-Year Follow-Up Optical Coherence Tomography Angiography Study

Background/Objectives: This study aims to investigate the long-term effect of inactive systemic lupus erythematosus (SLE) on the retinal microcirculation measured via optical coherence tomography angiography (OCT-A). Methods: Twenty-four eyes of 24 patients with inactive SLE under hydroxychloroquine (HCQ) therapy were included. The OCT-A data (mainly vessel density (VD) and foveal avascular zone (FAZ) data of the superficial and of the deep capillary plexus (SCP, DCP) and the choriocapillaris (CC)) were analyzed and compared between the baseline examination (t0) and 2 years later (t1). Results: At t1, VD in the whole en face SCP and in the CC was notably reduced compared to t0 (SCP: p = 0.001, CC: p = 0.013). VD in the DCP, CRT and FAZ area showed no difference at t1 compared to t0 (DCP: p = 0.128, FAZ: p = 0.332, CRT fovea: p = 0.296). Correlation analysis between the increase in cumulative doses of HCQ between t0 and t1 and the VD of the whole en face SCP did not show any correlation (Spearman r = 0.062 (95% CI -0.367; 0.477). Conclusions: SLE patients demonstrated a decrease in the retinal VD of the SCP and CC over a 2-year period. There was no correlation with the change in cumulative doses of HCQ. These results suggest an ongoing effect of the disease on the retinal and choriocapillary microcirculation.

Comparative quantitative analysis of optical coherence tomography angiography in varied morphologies of macular neovascularization following intravitreal conbercept and ranibizumab treatments for neovascular age‑related macular degeneration

The present study aimed to examine the optical coherence tomography angiography (OCTA) parameters associated with macular neovascularization (MNV) in patients diagnosed with neovascular age-related macular degeneration (nAMD) and treated with either intravitreal conbercept (IVC) or ranibizumab (IVR). It enrolled 39 nAMD patients presenting with MNV, including 23 in the IVC group and 16 in the IVR group. All participants were treatment-naïve with intravitreal therapy and they underwent treatment following a '3+PRN' regimen. The MNV patterns identified through OCTA were categorized as Medusa, tangled, seafan and other variations. Key outcome measures encompassed best-corrected visual acuity (BCVA), MNV vascular area (MNV-VA), MNV vascular density (MNV-VD) ratio and central macular thickness (CMT). In the present study, 44 eyes were included, with 28 eyes undergoing treatment with IVC and 18 eyes with IVR. On day 90, there was a statistically significant improvement in mean BCVA from baseline among all patients treated with IVC (P=0.002). Notably, improved outcomes were observed in those with the 'tangled' pattern compared with the other three patterns (P=0.007). CMT exhibited a significant decrease from baseline (P=0.007), with consistent improvement observed across all four patterns (P=0.052) on day 90. The mean MNV-VA decreased in all patients, reaching statistical significance for the Medusa pattern (P=0.008), although the improvement in visual acuity was deemed unsatisfactory. Patients with the seafan pattern treated with IVR improved significantly in BCVA (P=0.042). The mean CMT significantly improved from baseline (P=0.001), consistent across the four patterns (P=0.114). Significant improvements were noted in the mean MNV-VA for the seafan pattern and in the mean MNV-VD ratio for the other patterns. The two regimens had no significant differences regarding BCVA, CMT, and MNV parameters. Conbercept emerged as a viable treatment option for patients presenting with tangled MNV patterns. On the other hand, ranibizumab might be considered an effective intervention for individuals with seafan MNV patterns. Notably, the Medusa MNV pattern was associated with a morphologic configuration indicative of a poor prognosis.

Reduced Retinal Blood Vessel Densities Measured by Optical Coherence Tomography Angiography in Keratoconus Patients Are Negatively Correlated with Keratoconus Severity

Keratoconus (KC) is the most common corneal ectasia. Optical coherence tomography angiography (OCT-A) is a relatively new non-invasive imaging technique that allows the visualization and quantification of retinal and choriocapillary blood vessels. The aim of this study is to assess retinal and choriocapillary vessel density (VD) differences between KC patients and healthy controls and to investigate correlations between VD and KC severity. Fifty-two eyes were included in this exploratory study: twenty-six eyes from 26 KC patients and twenty-six eyes from 26 age- and gender-matched healthy controls. All patients underwent Scheimpflug corneal topography with Pentacam, axis lengths measurement and optical coherence tomography angiography (OCT-A). The thinnest spot in corneal pachymetry, maximum K (Kmax) and KC severity indices from the Belin/Ambrósio enhanced ectasia display (BAD) were also assessed. There was a distinct reduction particularly in the retinal VD of the superficial capillary plexus (SCP). Correlation analyses showed strong and moderate negative correlations between the VD in the macular SCP and BAD KC scores and between the SCP VD and Kmax. There was no difference in retinal thickness between the KC and healthy controls. With this study, further evidence for altered VD measurements by OCT-A in KC patients is given. For the first time, we demonstrated negative correlations between BAD KC scores and retinal blood vessel alterations. A major limitation of the study is the relatively small sample size. Since an artefactual reduction of the quantitative OCT-A measurements due to irregular corneal topography in KC must be assumed, it remains to be investigated whether there are also actual changes in the retinal microcirculation in KC.

Chronic renal failure as predictive factor for acute elevation of systolic blood pressure after fluorescein angiography in patients with retinal diseases

Purpose

To investigate the influence of fluorescein angiography (FA) on blood pressure (BP) in patients with retinal diseases, and analyze the predictive factors for acute elevation of systolic BP after FA.

Design

and Methods: A prospective study was conducted with 636 patients undergoing FA between April 2021 and October 2021. BP and pulse were measured in each patient before and 20 min after FA. The baseline characteristics of patients who developed an acute elevation in systolic BP (>10 mmHg) were compared with those of the remaining patients to detect factors that may predict this acute elevation.

Results

Overall, mean systolic BP changed from 142 ± 17 mmHg to 140 ± 20 mmHg after 20 min (p = 0.1). Mean diastolic BP changed from 79 ± 15 mmHg to 78 ± 13 mmHg after 20 min (p = 0.45). Mean pulse rate changed from 73 ± 14 bpm to 70 ± 12 bpm after 20 min (p = 0.001). 103 patients (16 %) had acute elevation of systolic BP (>10 mmHg). Mean systolic BP changed from 143 ± 17 mmHg to 162 ± 19 mmHg after 20 min in this group (p = 0.001). Patients in this group were significantly older compared to the rest (73 ± 12 vs 67 ± 15, p = 0.001). The rate of chronic renal failure was significantly higher in this group compared to the rest of the patients (42/7.8 % vs 15/14.6 %, p = 0.01).

Conclusions

This study demonstrated that fluorescein angiography is a relatively safe procedure with regards to blood pressure changes. However, chronic renal failure could be considered as predictive factor for acute elevation of systolic blood pressure after this procedure.

Endpoints for clinical trials in ophthalmology

With the identification of novel targets, the number of interventional clinical trials in ophthalmology has increased. Visual acuity has for a long time been considered the gold standard endpoint for clinical trials, but in the recent years it became evident that other endpoints are required for many indications including geographic atrophy and inherited retinal disease. In glaucoma the currently available drugs were approved based on their IOP lowering capacity. Some recent findings do, however, indicate that at the same level of IOP reduction, not all drugs have the same effect on visual field progression. For neuroprotection trials in glaucoma, novel surrogate endpoints are required, which may either include functional or structural parameters or a combination of both. A number of potential surrogate endpoints for ophthalmology clinical trials have been identified, but their validation is complicated and requires solid scientific evidence. In this article we summarize candidates for clinical endpoints in ophthalmology with a focus on retinal disease and glaucoma. Functional and structural biomarkers, as well as quality of life measures are discussed, and their potential to serve as endpoints in pivotal trials is critically evaluated.

Correlation of the OCT Double-Layer Sign with Type 1 Non-Exudative Neovascularization on OCT-A in Age-Related Macular Degeneration

Background and Objectives: Early diagnosis of the exudative form of age-related macular degeneration (AMD) is very important for a timely first treatment, which is directly related to the preservation of functional visual acuity over a long period. The goal of this paper was to examine the correlation between the double-layer sign (DLS) and the presence of non-exudative macular neovascularization (MNV). Materials and Methods: Our research included 60 patients with AMD, exudative in one eye and non-exudative in the other eye. We analyzed only the non-exudative form using optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A). The patients were classified into three groups, depending on the duration of the disease (<2 years, 2 to 5 years, >5 years). The onset of the disease was deemed the moment of establishing a diagnosis of exudative AMD in one eye. We defined the presence or absence of a DLS using OCT and the presence of non-exudative MNV using OCT-A, both on 3 × 3 mm and 6 × 6 mm sections. DLS was used as a projection biomarker for non-exudative MNV, with the aim of establishing a rapid diagnosis and achieving early treatment of the disease. Results: We found that there was a statistically significant correlation between the DLS diagnosed using OCT and non-exudative MNV diagnosed by OCT-A for both 3 × 3 mm (p < 0.001) and 6 × 6 mm (p < 0.001) imaging. There was a statistically significant difference between the frequencies of both DLS and MNV in Groups I and III on both 3 × 3 and 6 × 6 mm imaging. A statistically significant difference was also noted in the frequencies of DLS and MNV on 6 × 6 mm imaging, but not on 3 × 3 mm imaging, between Groups I and II. No differences were found between the frequencies of DLS and MNV between Groups II and III. Conclusions: The DLS on OCT can be used as a projection biomarker to assess the presence of a non-exudative MNV.

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).

Clinical Use of Optical Coherence Tomography Angiography in Retinal Diseases

The advent of optical coherence tomography angiography (OCTA) is one of the cornerstones of fundus imaging. Essentially, its mechanism depends on the visualization of blood vessels by using the flow of erythrocytes as an intrinsic contrast agent. Although it has only recently come into clinical use, OCTA has become a non-invasive diagnostic tool for the diagnosis and follow-up of many retinal diseases, and the integration of OCTA in multimodal imaging has provided a better understanding of many retinal disorders. Here, we provide a detailed overview of the current applications of OCTA technology in the diagnosis and follow-up of various retinal disorders.

Optometrists' attitudes toward using OCT angiography lag behind other retinal imaging types

PURPOSE

While optometrists' attitudes toward established retinal imaging types are generally positive, they are unknown for optical coherence tomography angiography (OCTA). We performed a cross-sectional survey to estimate attitudes toward OCTA and identify clinician and/or practice characteristics that influence them.

METHODS

A paper-based survey was mailed to 252 randomly selected optometrists in Australia. Five-point Likert-scale items from a previous survey assessing attitudes toward new technology were included to probe respondent characteristics and attitudes toward retinal imaging. Performance expectancy attitudes toward OCTA were elicited by the statement 'I believe OCTA is useful in daily practice'. Mean scores out of five (mean [SD]) were rounded and mapped to appropriate descriptive statements.

RESULTS

The response rate was 47% (118/252). The mean (SD) age of respondents was 44.0 (13.8) years and 50.8% (60/118) were female. Optometrists had 19.9 (14.0) years of clinical experience and 66.9% (79/118) worked at independent practices. In total, 8.5% (10/118) of respondents used OCTA to provide clinical care. Optometrists agreed that optical coherence tomography (OCT), colour fundus imaging, ultra-wide field imaging and fundus autofluorescence (mean scores 3.6-4.7 out of 5) were useful in daily practice but felt neutral about whether OCTA was useful (3.4 [0.8]). Optometrists believed that OCTA was less enjoyable to use (p < 0.0001), less endorsed by peers (p < 0.0001) and felt less confident that they had the knowledge to interpret OCTA (p < 0.0001) compared to other retinal imaging types.

CONCLUSIONS

Optometrists are undecided on whether OCTA is useful in daily practice and had lower expectations that using OCTA would confer job performance benefits compared to other retinal imaging types. Further work is needed to advocate the benefits of using OCTA across the profession.

Practical guidance for imaging biomarkers in exudative age-related macular degeneration

We provide an overview of current macular imaging techniques and identify and describe biomarkers that may be of use in the routine management of macular diseases, particularly exudative age-related macular degeneration (n-AMD). This perspective includes sections on macular imaging techniques including optical coherence tomography (OCT) and OCT angiography (OCTA), classification of exudative AMD, and biomarkers in structural OCT and OCTA. Fluorescein angiography remains a vital tool for assessing the activity of neovascular lesion, while indocyanine green angiography is the preferred option for choroidal vessels imaging in neovascular AMD. OCT provides a non-invasive three-dimensional visualization of retinal architecture in vivo and is useful in the diagnosis of many imaging biomarkers of AMD-related neovascular lesions including lesion activity. OCTA is a recent advance in OCT technology that allows accurate visualization of retinal and choroidal vascular flow. OCT and OCTA have led to an updated classification of exudative AMD lesions and provide several biomarkers that help to establish a diagnosis and the disease activity status of neovascular lesions. Individualization of therapy guided by OCT and OCTA biomarkers has the potential to further improve visual outcomes in exudative AMD. Moving forwards, integration of technologically advanced imaging equipment with AI software will help ophthalmologists to provide patients with the best possible care.

Optical coherence tomography angiography for the detection of macular neovascularization-comparison of en face versus cross-sectional view

PURPOSE

To evaluate sensitivity and specificity of swept source-optical coherence tomography angiography (SS-OCTA) en face images versus cross-sectional OCTA versus a combination of both for the detection of macular neovascularization (MNV).

DESIGN

Prospective cohort study.

PARTICIPANTS

Consecutive patients with various chorioretinal diseases and subretinal hyperreflective material (SHRM) and/or pigment epithelial detachment (PED) on OCT possibly corresponding to MNV in at least one eye.

METHODS

102 eyes of 63 patients with fluorescein angiography (FA), OCT and SS-OCTA performed on the same day were included. FA images, the outer retina to choriocapillaris (ORCC) OCTA en face slab, a manually modified en face slab ('custom slab'), cross-sectional OCTA and a combination of OCTA en face and cross-section were evaluated for presence of MNV.

MAIN OUTCOME MEASURES

Sensitivity and specificity for MNV detection, as well as the concordance was calculated using FA as the reference.

RESULTS

OCTA en face imaging alone yielded a sensitivity of 46.3% (automated)/78.1% (custom) and specificity of 93.4% (automated)/88.5% (custom) for MNV detection. Cross-sectional OCTA (combination with en face) resulted in a sensitivity of 85.4% (82.9%) and specificity of 82.0% (85.3%). Concordance to FA was moderate for automated en face OCTA (κ = 0.43), and substantial for custom en face OCTA (κ = 0.67), cross-sectional OCTA (κ = 0.66) and the combination (κ = 0.68).

CONCLUSION

Segmentation errors result in decreased sensitivity for MNV detection on automatically generated OCTA en face images. Cross-sectional OCTA allows detection of MNV without manual modification of segmentation lines and should be used for evaluation of MNV on OCTA.

Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives

When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.

Detection of pachychoroid neovasculopathy with optical coherence tomography angiography versus dye angiography imaging

BACKGROUND

To investigate the sensitivity and specificity of optical coherence tomography angiography (OCTA) versus dye angiography for detecting pachychoroid neovasculopathy (PNV) and to determine the morphological factors that affect PNV detection.

METHODS

Patients with pachychoroid phenotype were prospectively enrolled and underwent multimodal imaging examinations during the same visit. The diagnostic accuracy of fundus fluorescein angiography (FFA), FFA combined with indocyanine green angiography (ICGA) and OCTA for PNV was evaluated using multimodal imaging as the reference. Multimodal parameters of PNV were qualitatively and quantitatively assessed.

RESULTS

PNV was detected in 58 eyes (46 patients) out of 340 pachychoroid eyes (201 patients) according to reference standard. Patients with PNV eyes were significantly older (54.6±7.56 vs. 48.2±9.1 years), were more likely to have a chronic central serous chorioretinopathy history (CSC) (93.1% vs. 12.4%) and had a worse visual acuity (0.30±0.22 vs. 0.58±0.30) than those without PNV eyes (all P<0.001). The sensitivity of FFA, FFA combined with ICGA, and OCTA in detecting PNV in patients with the pachychoroid phenotype was 67.2%, 63.8% and 98.3%, respectively, and the specificity was 87.2%, 96.8% and 100.0%, respectively. PNV not identified by dye angiography was more manifested as the absence of late plaque hypercyanescence on ICGA (P<0.001) and overall smaller capillaries without a distinct pattern (P=0.001), fewer core vessels (P=0.002) and smaller area (P=0.044).

CONCLUSIONS

OCTA showed superior detection rate and accuracy for identifying PNV over dye angiography. In case multimodal imaging is unavailable, OCTA can be an effective and noninvasive method for monitoring PNV and guiding treatment decisions.

Undetectable Macular Neovascularization on OCT Angiography in Age Related Macular Degeneration: Comparison between Different Devices

Background and Objectives: The aim of this study was to report the characteristics of macular neovascularization (MNV) with undetectable flow on optical coherence tomography angiography (OCTA) in neovascular age related macular degeneration (nAMD), and compare them with the characteristics of detectable MNV. Materials and Methods: Patients with a diagnosis of nAMD who underwent dye imaging and OCTA in the same day were included and divided into two groups: undetectable and detectable flow on OCTA. Three OCTA devices were used, two with spectral-domain technology (AngioVue, RTVue 100xAvanti, Optovue, Freemont, CA, USA and Heidelberg OCT2 Beta Angiography Module, Heidelberg Engineering, Germany) and one swept-source OCTA (PlexElite 9000; Carl Zeiss Meditec, Inc., Dublin, CA, USA). We studied the demographics, neovascularization characteristics, and OCTA device and acquisition characteristics for both groups. Results: A global comparison between Group 1 and Group 2 was made, followed by an analysis of variables associated with (un)detectability for each OCTA device. A total of 108 eyes were included: 90 in the detectable group (Group 1) and 18 in the undetectable group (Group 2), corresponding to a global sensitivity of OCTA for the detection of MNV of 83.49%. There was a statistically significant difference between the two groups regarding MNV type (p = 0.02) and PED height (p = 0.017). For the three devices, detection sensitivity with automatic segmentation was significantly lower than with manual segmentation. For Heidelberg, PED Height and scan quality explained 68.3% of the undetectability. For AngioVue, PED Height and absence of hemorrhage explained 67.9% of undetectability. Conclusions: In this study, we found a global sensitivity of 83.49% for the three OCTA devices combined, with a range from 55.5% to 96.26% depending on the segmentation and OCTA device. This means that undetectable/undetected MNV can represent up to 45% of the examinations, eventually misdiagnosing choroidal neovascularization for 1 out every 2 patients.

Optical Coherence Tomography Angiography: Clinical Utility and Future Directions

Purpose

This work aims to review the principles of optical coherence tomography angiography (OCTA), to survey its clinical utility, and to highlight the strengths of this technology as well as barriers to adoption.

Methods

A literature review with editorial discussion of the current applications for OCTA is presented.

Results

There have been recent advances in multiple domains in OCTA imaging, including devices, algorithms, and new observations pertaining to a range of pathologies. New devices have improved the scanning speed, signal-to-noise ratio, and spatial resolution and offer an increased field of view. New algorithms have been proposed to optimize image processing and reduce artifacts. Numerous studies employing OCTA have been published describing changes to the microvasculature in diabetic retinopathy, age-related macular degeneration, central serous chorioretinopathy, retinal vein occlusion, and uveitis.

Conclusions

OCTA provides noninvasive, high-resolution volumetric scans of the retinal and choroidal vasculature. OCTA can provide valuable data to augment traditional dye-based angiography in a range of chorioretinal diseases.

Masking of macular neovascular membranes by subretinal hyperreflective material on optical coherence tomography angiography

PURPOSE

The purpose of this study was to determine whether subretinal hyperreflective material (SHRM) may mask the detection of macular neovascular membranes (MNV) on optical coherence tomography angiography (OCTA).

METHODS

In this observational study, eyes with active neovascular age-related macular degeneration (nAMD), co-existing SHRM & intraretinal or subretinal fluid or hemorrhage on structural OCT, underwent OCTA & fundus fluorescein angiography (FFA) imaging. 6 × 6 mm choriocapillaris and outer retinal slabs on OCTA were examined to determine the presence of MNV underneath the SHRM. The corresponding area on FFA was used as a reference arm to confirm activity.

RESULTS

Thirty eyes of thirty patients with SHRM and active nAMD were recruited. All eyes failed to show a MNV in the choriocapillaris & avascular slabs of the OCTA underneath the SHRM, but showed active hyperfluorescent MNVs that increased in size and intensity in the late stages of FFA. In one eye, parts of a MNV under the SHRM were undetectable due to signal attenuation, while parts extending beyond the SHRM were detected on the choriocapillaris en face slab with flow on the B scan.

CONCLUSIONS

SHRM may act as a reflecting surface that limits the passage of light waves in OCTA, creating areas of signal attenuation and diminishing its ability to detect underlying MNVs.

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.

Neovascular age-related macular degeneration: advancement in retinal imaging builds a bridge between histopathology and clinical findings

PURPOSE

To provide a review of the salient histological and imaging features in neovascular age-related macular degeneration (AMD) that will be integrated in order to have a better comprehension of the pathogenesis and clinical aspects of this disease.

METHODS

A literature review of histology and imaging features in neovascular AMD was conducted.

RESULTS

Histology has granted a detailed characterization of neovascular AMD ex vivo. In details, histological features in these eyes have offered important insights into the pathogenesis of neovascular AMD. In addition, histology donated a detailed characterization of the different types of macular neovascularization (MNV) that may complicate AMD. The introduction of optical coherence tomography angiography (OCTA) has enormously amplified our knowledge of neovascular AMD through in vivo assessment of the anatomical and pathological characteristics of this disease. New insights elucidating the morphological features of the choriocapillaris confirmed that this vascular structure plays a crucial role in the pathogenesis of neovascular AMD. OCTA also offered a detailed visualization of MNV complicating neovascular AMD.

CONCLUSIONS

New imaging technologies offer a remarkable chance to build a bridge between histology and clinical findings in neovascular AMD.

Advances and Current Clinical Applications of Anterior Segment Optical Coherence Tomography Angiography

Optical coherence tomography angiography (OCTA) is the most relevant evolution based on optical coherence tomography (OCT). OCTA can present ocular vasculature, show detailed morphology for assessment, and quantify vessel parameters without intravenous dye agent. Research on the anterior segment OCTA (AS-OCTA) is only in its initial phase, and its advances in clinical diagnosis and treatment efficacy evaluations require a detailed comparison to traditional imaging methods. In this review of AS-OCTA, we summarize its technical features, imaging advances, current clinical applications in various eye diseases, as well as its limitations and potential future directions. AS-OCTA offers potential advantages in ophthalmic imaging, and with further development it could become a common tool in the near future.

Redefining response in wet AMD to anti VEGF therapy based on non-OCTA versus OCTA evaluation

PURPOSE

Anti vascular endothelial growth factor (anti VEGF) has been the mainstay of treatment in wet age-related macular degeneration (AMD). Subsequent decision to continue anti VEGF therapy depends on the treatment response quantified by functional (visual acuity) and morphological (optical coherence tomography) parameters then categorized from good to poor.

METHODS

This study evaluates the agreement between OCT angiography (OCTA) and non-OCTA (logMAR VA plus OCT) to decide anti-VEGF treatment's continuity. After an anti VEGF treatment, on a follow up visit, a patient underwent non-OCTA evaluation (decision A) then OCTA evaluation (decision B) to judge the necessity of future anti VEGF application.

RESULTS

Out of 129 eyes, on 72 eyes (49%), there were agreements on both decision arms, but on 55 eyes (42%) there was disagreement. Particularly, disagreement on 47/55 eyes was important, where OCTA advised "continue anti VEGF" and non-OCTA advised "Stop anti VEGF" therapy. Cohen's Kappa for probability of agreement to continue anti VEGF was fair (0.33) and to stop anti VEGF therapy was none (0.1).

CONCLUSIONS

Based on resulting disagreements between the two modalities on deciding the continuity of anti VEGF, we conclude that OCTA must be considered in the conventional decision making algorithm in patients with wet AMD under anti VEGF therapy.

The Diagnostic Capability of Swept Source OCT Angiography in Treatment-Naive Exudative Neovascular Age-Related Macular Degeneration

Purpose

To evaluate the capability of swept source-optical coherence tomography angiography (SS-OCTA) in the detection and localization of treatment-naive macular neovascularization (MNV) secondary to exudative neovascular age-related macular degeneration (nAMD).

Methods

In this prospective, observational case series, 158 eyes of 142 patients were diagnosed with exudative nAMD using fluorescein (FA) and indocyanine green angiography (ICGA) and evaluated by SS-OCTA in a tertiary retina center (Rudolf Foundation Hospital Vienna, Austria). The main outcome measure was the sensitivity of SS-OCTA compared to the standard multimodal imaging approach. Secondary outcome measure was the anatomic analysis of MNV in relation to the retinal pigment epithelium.

Results

En-face SS-OCTA confirmed a MNV in 126 eyes (sensitivity: 79.8%), leaving 32 eyes (20.2%) undetected. In 23 of these 32 eyes (71.9%), abnormal flow in cross-sectional SS-OCTA B-scans was identified, giving an overall SS-OCTA sensitivity of 94.3%. Eyes with a pigment epithelium detachment (PED) ≥ 300 μm had a smaller probability for correct MNV detection (p=0.015). Type 1 MNV showed a trend (p=0.051) towards smaller probability for the correct detection compared to all other subtypes. Other relevant factors for the nondetection of MNV in SS-OCTA were image artifacts present in 3 of 32 eyes (9.4%). SS-OCTA confirmed the anatomic localization of 93 in 126 MNVs as compared to FA (sensitivity: 73.8%). There was no influence of age, gender, pseudophakia, visual acuity, central foveal thickness, or subfoveal choroidal thickness on the detection rate of MNV.

Conclusions

SS-OCTA remains inferior to dye-based angiography in the detection rate of exudative nAMD consistent with type 1 MNV and a PED ≥300 µm. The capability to combine imaging modalities and distinguish the respective MNV subtype improves its diagnostic value.

Comparison of swept-source versus spectral-domain optical coherence tomography angiography for detection of macular neovascularization

Purpose

To compare swept-source (SS) versus spectral-domain (SD) optical coherence tomography angiography (OCTA) for the detection of macular neovascularization (MNV).

Methods

In this prospective cohort study, 72 eyes of 54 patients with subretinal hyperreflective material (SHRM) and/or pigment epithelial detachment (PED) on OCT possibly corresponding to MNV in at least one eye were included. OCTA scans were acquired using two devices, the PLEX Elite 9000 SS-OCTA and the Spectralis SD-OCTA. Fluorescein angiography (FA) was used as reference. Two graders independently evaluated en face OCTA images using a preset slab as well as a manually modified slab, followed by a combination of en face and cross-sectional OCTA.

Results

Sensitivity (specificity) for the automated slabs was 51.7% (93.0%) for SS-OCTA versus 58.6% (95.3%) for SD-OCTA. Manual modification of segmentation increased sensitivity to 79.3% for SS-OCTA but not for SD-OCTA (58.6%). The combination of en face OCTA with cross-sectional OCTA reached highest sensitivity values (SS-OCTA: 82.8%, SD-OCTA: 86.2%), and lowest number of cases with discrepancies between SS-OCTA and SD-OCTA (4.2%). Fleiss kappa as measure of concordance between FA, SS-OCTA, and SD-OCTA was 0.56 for the automated slabs, 0.60 for the manual slabs, and 0.73 (good agreement) for the combination of en face OCTA with cross-sectional OCTA. Concordance to FA was moderate for the automated slabs and good for manual slabs and combination with cross-sectional OCTA of both devices.

Conclusion

Both devices reached comparable results regarding the detection of MNV on OCTA. Sensitivity for MNV detection and agreement between devices was best when evaluating a combination of en face and cross-sectional OCTA.

PRESUMED FOVEAL BACILLARY LAYER DETACHMENT IN A PATIENT WITH TOXOPLASMOSIS CHORIORETINITIS AND PACHYCHOROID DISEASE

PURPOSE

To report a detachment that apparently separated photoreceptor inner segment myoids from inner segment ellipsoids as a manifestation of toxoplasmosis chorioretinitis in a patient with pachychoroid spectrum disease.

METHODS

Multimodal imaging including fundus photography, spectral domain and enhanced-depth imaging optical coherence tomography (OCT), indocyanine green angiography, and OCT angiography.

RESULTS

A 33-year-old man with a history of toxoplasmosis chorioretinitis reported 1 week of decreased vision to 20/200 in his right eye. Examination of the right eye demonstrated mild vitritis with recurrent chorioretinitis inferior to the fovea and adjacent to a chorioretinal scar. A dome-shaped, foveal photoreceptor layer-splitting detachment was noted on OCT. Because degenerating cone photoreceptors are capable of shedding their inner segments, we inferred the location of the detachment at the level of the inner segment myoid and provided a histological example of such from an unrelated donor case. In addition, multimodal imaging revealed dilated choroidal veins (pachyvessels) with attenuation of the inner choroid in both eyes and asymptomatic findings of central serous chorioretinopathy in the left eye. After 1 month of antibiotic and steroid therapy, the chorioretinitis resolved, as did the detachment. Hyperreflective foci on the vitreoretinal interface were appreciated with en face OCT that appeared to aggregate throughout the course of therapy, induce inner retinal striae, and resolve without inducing epiretinal membrane formation.

CONCLUSION

Patients with preexisting pachychoroid spectrum disease may manifest a more significant retinal fluid accumulation in the setting of superimposed chorioretinal inflammation. In this case of macular toxoplasmosis chorioretinitis, inflammation manifested as a retinal detachment at the level of photoreceptor inner segment myoids that we named as a bacillary layer detachment. In this case, inflammatory sequelae of toxoplasmosis reactivation responded well to oral and intravitreal therapy.

COMPARISON BETWEEN SEVERAL OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY DEVICES AND INDOCYANINE GREEN ANGIOGRAPHY OF CHOROIDAL NEOVASCULARIZATION

PURPOSE

To compare indocyanine green angiography and four different optical coherence tomography angiography (OCTA) devices and to test their reproducibility in the evaluation of choroidal neovascularization (CNV).

METHODS

This study was an observational case series of Type 1 and Type 2 CNV presenting at the Eye Clinic, Department of Biomedical and Clinical Sciences, Luigi Sacco Hospital, University of Milan, imaged with indocyanine green angiography and four different OCTA devices: prototype PlexElite (Carl Zeiss Meditec), prototype Spectralis OCTA (Spectralis; Heidelberg Engineering, Heidelberg, Germany), Optovue RTVue XR Avanti (Optovue, Inc, Fremont, CA), and AngioPlex (Cirrus 5000 HD-OCT; Carl Zeiss Meditec, Inc, Dublin, CA). Optical coherence tomography angiography examinations were performed using a 3 × 3-mm or 6 × 6-mm volume scan pattern to capture the full lesion. The mean area of CNV, vessel density, and fractal dimension were compared between the devices.

RESULTS

Seventeen eyes of 17 patients with CNV were enrolled. The CNV area was significantly larger in indocyanine green angiography than in the OCTA devices. Moreover, the four different instruments produced measurements with different mean values of CNV area, vessel density, and fractal dimension. The Bland-Altman analysis revealed that the limits of agreement for the comparisons were not acceptable.

CONCLUSION

The choroidal neovascularization area is larger when imaged with standard indocyanine green angiography than with different OCTA devices with different algorithms, wavelengths, and scan patterns. The differences between several OCTA devices in the evaluation of quantitative parameters of CNV, such as CNV area, vessel density, and fractal dimension, suggest the necessity to standardize OCTA measurements for research and clinical practice.

CHOROIDAL NEOVASCULAR AREA AND VESSEL DENSITY COMPARISON BETWEEN TWO SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY DEVICES

PURPOSE

To compare choroidal neovascularization (CNV) area and vessel density (VD) measurements between two different swept-source optical coherence tomography angiography (SS-OCTA) devices.

METHODS

En face optical coherence tomography angiography (OCTA) images of patients affected by neovascular age-related macular degeneration were collected prospectively from two devices: Zeiss PLEX Elite 9000 (Carl Zeiss Meditec, Dublin, CA) and Topcon DRI OCT Triton SS-OCTA (Topcon, Tokyo, Japan). Choroidal neovascularization area and VD of images were measured and analyzed with ImageJ software by two readers to evaluate the agreement between two devices, with respect to different image size (3 × 3 and 6 × 6 mm) and different image segmentation (automatic vs. manual), and a Topcon equivalent Zeiss segmentation as control (i.e., the equivalent anatomical slab given by Topcon device on the Zeiss device).

RESULTS

A total of 30 eyes (30 patients) were analyzed. There was an excellent agreement between the two readers in CNV area measurements intraclass correlation coefficient >0.9 in all analyses. We found excellent agreement in CNV area measurements (manual and automatic segmentations) when comparing 3 × 3-mm or 6 × 6-mm images both for each single device and between the two devices (overall intraclass correlation coefficient > 0.9). Vessel density measurements between manual to automatic segmentation within the same device and same image size had a high intraclass correlation coefficient value, but there was a poor agreement in VD between different image sizes (3 × 3 mm vs. 6 × 6 mm) in the same device and also comparing the two devices (3 × 3 Topcon vs. 3 × 3 Zeiss; 6 × 6 Topcon vs. 6 × 6 Zeiss). There was a poor agreement between the Topcon equivalent Zeiss segmentation and all other segmentations.

CONCLUSION

There was an excellent agreement in CNV area measurements for both swept-source optical coherence tomography angiography devices in automatic and manual segmentations. However, the Topcon equivalent Zeiss segmentation was not comparable with any of the preset segmentations of Topcon and Zeiss devices. There was a poor agreement in CNV VD between different image size and different devices. For these reasons, it seems that, for accurate longitudinal analysis of VD, it is better to use the same device for each individual, even if both devices can be used interchangeably for CNV area measurements using automatic or manual segmentations.

Comparison of macular neovascularization lesion size by the use of Spectral-Domain Optical Coherence Tomography Angiography and Swept-Source Optical Coherence Tomography Angiography versus Indocyanine Green Angiography

PURPOSE

To compare the lesion sizes of macular neovascularization (MNV) imaged with spectral-domain (SD) and swept-source (SS) optical coherence tomography angiography (OCTA) as well as indocyanine green angiography (ICGA).

METHODS

In this prospective, observational case series, patients showing a secured diagnosis of MNV on ICGA or Fluorescein Angiography, were imaged by SD-OCTA and SS-OCTA on the same day. Lesion size was measured on 3 × 3-mm² and 6 × 6-mm² scans using the Maestro 2 SD-OCTA (Topcon Corporation, Tokyo Japan) and the Triton SS-OCTA device (Topcon Corporation, Tokyo Japan) and compared to ICGA (Spectralis HRA, Heidelberg, Germany).

RESULTS

Twenty eyes from 20 patients (11 females, 55%) were enrolled. The neovascularization area measured on 6 × 6-mm² SD-OCTA was lower compared to that outlined on SS-OCTA, however, not reaching statistical significance (p = 0.094). Regarding 3 × 3-mm² measurements, the median lesion sizes between the two OCTA devices were comparable (p = 0.492). Indocyanine green angiography depicted a larger lesion area than both OCTA devices, however, not reaching statistical significance.

CONCLUSION

SD-OCTA tends to show smaller areas of MNV extension than SS-OCTA regarding 6 × 6 mm² scans. The lesion size of MNV can be very well compared between the different devices, emphasizing the use of OCTA for monitoring neovascular area. Lesion measurements on SS-OCTA correlate better with ICGA than SD-OCTA.

Optical Coherence Tomography Angiography of the Choriocapillaris in Age-Related Macular Degeneration

The advent of optical coherence tomography angiography (OCTA) has allowed for remarkable advancements in our understanding of the role of the choriocapillaris in age-related macular degeneration (AMD). As a relatively new imaging modality, techniques to analyze and quantify choriocapillaris images are still evolving. Quantification of the choriocapillaris requires careful consideration of many factors, including the type of OCTA device, segmentation of the choriocapillaris slab, image processing techniques, and thresholding method. OCTA imaging shows that the choriocapillaris is impaired in intermediate non-neovascular AMD, and the severity of impairment may predict the advancement of disease. In advanced atrophic AMD, the choriocapillaris is severely impaired underneath the area of geographic atrophy, and the level of impairment surrounding the lesion predicts the rate of atrophy enlargement. Macular neovascularization can be readily identified and classified using OCTA, but it is still unclear if neovascularization features with OCTA can predict the lesion’s level of activity. The choriocapillaris surrounding macular neovascularization is impaired while the more peripheral choriocapillaris is spared, implying that choriocapillaris disruption may drive neovascularization growth. With continued innovation in OCTA image acquisition and analysis methods, advancement in clinical applications and pathophysiologic discoveries in AMD are set to follow.

Ocular Imaging for Enhancing the Understanding, Assessment, and Management of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a progressive neuro-retinal disease and the leading cause of central vision loss among elderly individuals in the developed countries. Modern ocular imaging technologies constitute an essential component of the evaluation of these patients and have contributed extensively to our understanding of the disease. A challenge with any review of ocular imaging technologies is the rapid pace of progress and evolution of these instruments. Nonetheless, for proper and optimal use of these technologies, it is essential for the user to understand the technical principles underlying the imaging modality and their role in assessing the disease in various settings. Indeed, AMD, like many other retinal diseases, benefits from a multimodal imaging approach to optimally characterize the disease. In this chapter, we will review the various imaging technologies currently used in the assessment and management of AMD.

SENSITIVITY OF 840-nm SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN DETECTING TYPE 1 NEOVASCULARIZATION ACCORDING TO THE HEIGHT OF THE ASSOCIATED PIGMENT EPITHELIAL DETACHMENT

PURPOSE

To evaluate the ability of optical coherence tomography angiography (OCTA) to detect abnormal vascular blood flow in Type 1 neovascularization (NV) with or without significant pigment epithelial detachment (PED).

METHODS

Consecutive age-related macular degeneration patients with either treatment-naive or anti-vascular endothelial growth factor-treated Type 1 NV were divided into 2 groups based on the PED height on structural OCT: greater than 250 μm (Group 1) versus less than 250 μm (Group 2). Two independent senior retina specialists analyzed the OCTA images (Zeiss Angioplex OCT, Carl Zeiss AG, Jena, Germany) using the automatic slabs alone (first reader) versus automatic and manual segmentation slabs (second reader).

RESULTS

In Group 1, 15 men and 42 women, aged from 51 years to 97 years (mean: 87.5), were included. Optical coherence tomography angiography was able to show an abnormal blood flow suggestive of Type 1 NV in 23 (40.3%) of 57 eyes for the first reader and in 32 (56.1%) of 57 eyes for the second reader. In Group 2, 7 men and 30 women, aged from 60 years to 96 years (mean: 80.2), were included. The first and second readers were able to observe an image suggestive of Type 1 NV in 33/37 (89.2%) and 37/37 (100%) of eyes, respectively.

CONCLUSION

The ability of OCTA to detect an abnormal blood flow in Type 1 NV was found to highly depend on the height of the associated PED and the use of manual segmentation slabs. Our results suggest that automatic slabs of OCTA should be interpreted with caution for the diagnosis of vascularized PED. The diagnosis of Type 1 NV using OCTA requires the use of manual segmentation and a multimodal imaging approach, especially when the height of the associated PED is >250 μm.

Evaluation of the inner choroid using OCT angiography

The advent of optical coherence tomography angiography (OCTA) has allowed a qualitative and quantitative analysis of the retinal vasculature and the choriocapillaris. With the use of OCTA, several studies evaluated the changes in the choriocapillaris showing how this vascular structure plays a significant role in the pathogenesis of different conditions. This article reviews the current methods of analysis of the choriocapillaris and the relevant findings in different chorioretinal diseases.

Recent advances in imaging technologies for assessment of retinal diseases

INTRODUCTION

Retinal imaging is a key investigation in ophthalmology. New devices continue to be created to keep up with the demand for better imaging modalities in this field. This review looks to highlight current trends and the future of retinal imaging.

AREAS COVERED

This review looks at the advances in topographical imaging, photoacoustic microscopy, optical coherence tomography and molecular imaging. There is future scoping on further advances in retinal imaging.

EXPERT OPINION

Retinal imaging continues to develop at a rapid pace to improve diagnosis and management of patients. We will see the development of big data to gain powerful insights and new technologies such as teleophthalmology mature in the future.

Evaluation of the clinical utility of optical coherence tomography angiography in age-related macular degeneration

Background/Aims

To evaluate the ability of optical coherence tomography angiography (OCTA) to identify the presence or absence of choroidal neovascularisation (CNV) and CNV activity in age-related macular degeneration (AMD).

Methods

Clinical parameters, fundus fluorescein angiogram and spectral-domain optical coherence tomography (SD-OCT) were used as the gold standard to determine disease activity. OCTA imaging was performed on the same day and was graded by two masked retina specialists for the presence or absence of CNV. Traditional multimodal imaging and OCTA findings were compared.

Results

One hundred and fifty-two eyes of 106 patients with AMD were retrospectively reviewed. Of these, 59 eyes had wet AMD and 93 had dry AMD with high-risk drusen. OCTA had 85.4% and 79.3% specificity and sensitivity, respectively, in determining the presence or absence of CNV. OCTA was 69.5% accurate in determining active CNV. False positives and negatives were 21.6% and 8.0%, respectively.

Conclusions

This study suggests that en-face OCTA images allow a moderate ability to identify CNV and that OCTA alone is weak at recognising active CNV requiring treatment in AMD.

OPTICAL COHERENCE TOMOGRAPHY, FLUORESCEIN ANGIOGRAPHY, AND DIAGNOSIS OF CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION

In a prospective study, spectral domain optical coherence tomography and fluorescein angiography, combined with color fundus photograph used as a first diagnostic test in patients aged 50 years or older, had a similar sensitivity and specificity for the diagnosis of choroidal neovascularization in age-related macular degeneration.

To determine the sensitivity and specificity of different retinal imaging combinations for the diagnosis of choroidal neovascularization (CNV) in age-related macular degeneration.

Microaneurysms visualisation using five different optical coherence tomography angiography devices compared to fluorescein angiography

Background

To compare fluorescein angiography (FA) and five different optical coherence tomography angiography (OCTA) devices and to test their reproducibility in the evaluation of retinal microaneurysms (MAs) secondary to diabetic retinopathy (DR).

Methods

On the same day, patients with DR were imaged with FA and five OCTA devices: prototype Spectralis OCTA, prototype PlexElite, RTVue XR Avanti, AngioPlex and DRI OCT Triton. For all OCTA devices, a 3×3 volume scan pattern was performed. MAs were evaluated for the superficial capillary plexus (SCP) and deep capillary plexus (DCP).

Results

Twenty eyes of 15 patients with DR were included. FA counted a significantly higher number of MAs compared to OCTA devices. Spectralis OCTA obtained a significantly higher number of MAs compared to PlexElite, RTVue XR Avanti, AngioPlex and DRI OCT Triton (p<0.0001). PlexElite and AngioPlex showed a greater number of MAs in the SCP, Spectralis OCTA, RTVue XR Avanti and DRI OCT Triton in the DCP. Higher sensitivity (43.3%) but lowest specificity (54.4%) was observed for Spectralis OCTA compared to other devices. The higher specificity (78.5%) and positive predictive value (83.3%) were observed for DRI OCT Triton.

Conclusions

FA remains the best imaging modality to visualise retinal MAs. Spectralis OCTA was able to detect more MAs compared to other devices, likely due to the higher number of B-scans in the scanned area as well as due to the higher number of repeated B-scans. The high variability between OCTA devices should be taken into account for future clinical trials as in clinical practice.

Comparison of different morphologies of choroidal neovascularization evaluated by ocular coherence tomography angiography in age-related macular degeneration

IMPORTANCE

The clinical implications of different morphologies of choroidal neovascularization (CNV), as evaluated by ocular coherence tomography angiography (OCTA) in neovascular age-related macular degeneration (nAMD), are lacking.

BACKGROUND

To describe the morphology of CNV in nAMD using OCTA, and to compare the visual prognosis and other structural OCT biomarkers between different morphologic patterns.

DESIGN

Retrospective cohort study.

PARTICIPANTS

One hundred and forty eyes with nAMD treated with anti-vascular endothelial growth factor (VEGF).

METHODS

Patients were examined using OCTA prior to and at 3, 6 and 12 months after receiving anti-VEGF therapy.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA) and morphologic retinal features.

RESULTS

Organized CNV was identified in 110/140 eyes (78.6%) using OCTA. These CNV complexes could be divided into three OCTA patterns: the 'medusa' pattern (n = 41), characterized by branching vessels radiating in all directions; the 'seafan' pattern (n = 43), characterized by branching vessels radiating to one side of the lesion; and the 'tangled' pattern (n = 26), characterized by globular entwined vessels without a main trunk. At baseline, the eyes with the tangled pattern were from younger patients (P = .031) with better BCVA (P = .007). There were also fewer intraretinal cysts (P = .021), less fibrovascular pigment epithelial detachment (P = .009), and more pachychoroid (P = .007) in eyes with the tangled pattern on OCT. At 12 months post-treatment, patients with the tangled CNV pattern also showed greater visual improvement than patients with the other two patterns (P = .049).

CONCLUSIONS AND RELEVANCE

Using OCTA, distinct morphologies of CNV in nAMD patients were identified. These different patterns might be useful predictors for the prognosis of nAMD patients after anti-VEGF therapy.

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.

[Indications for fluorescein angiography and optical coherence tomography angiography (OCTA) in medical retina: Changes from 2015 and 2018]

INTRODUCTION

Non-invasive multimodal imaging, including optical coherence tomography angiography (OCTA), has demonstrated high sensitivity and specificity for the management of retinal diseases. Since the availability of OCTA in 2015, we have developed a policy of "as little fluorescein angiography as possible". In this study, we describe the rate of OCTA and fluorescein angiography (FA) performed and their indications.

METHODS

Retrospective descriptive single-centre study. Chart review of patients examined for retinal disorders by one medical retina specialist between January 2015 and June 2018.

RESULTS

3487 patients were examined for a retinal disease. The charts of 651 of these patients (1170 eyes) were randomly selected for analysis (study group). The mean age in the study group was 72 years (60% female). Overall, OCTA and FA were performed in 49.4% and 6.5% of the studied eyes respectively. After the first year, the rate of FA decreased to 2%. The main indications for OCTA were age-related macular degeneration (AMD): 50%, central serous chorioretinopathy (CSC): 12% and retinal vascular occlusion: 10%. The most frequent indications for FA were AMD: 49%, diabetic retinopathy (DR): 18% and CSC: 14%. FA was performed in 16%, 11% and 10% of eyes diagnosed with DR, CSC and AMD respectively (P<0.05).

CONCLUSION

In routine practice, OCTA was performed in half of the eyes examined for a retinal disorder. The overall rate of FA was 6.5% and dropped to 2% after the first year of OCTA use. DR was the main disorder still requiring FA.

Features and Diagnostic Accuracy of Optical Coherence Tomography Angiography in Neovascular Age-related Macular Degeneration

Introduction Age-related macular degeneration (AMD) is one of the important causes of visual impairment in aging population. Fundus fluorescein angiography (FFA) is gold standard for the diagnosis of neovascular AMD (nAMD) while optical coherence tomography (OCT) aids in the diagnosis of nAMD and is very useful for follow-up. OCT angiography (OCTA) is an evolving imaging technology that can be used as a valid diagnostic tool to study morphology of choroidal neovascularization (CNV) that is seen in nAMD. This study was conducted with the objective to determine diagnostic accuracy and OCTA features of occult and classic CNV in patients with nAMD. Methods In this prospective observational study, 90 eyes of 58 patients with nAMD were studied with OCT, OCTA and FFA. OCTA scans were analyzed to qualitatively describe the morphological appearance of CNV in terms of location, pattern and configuration. The OCTA sensitivity and specificity for CNV detection were calculated by comparing it with FFA. Results FFA detected CNV in 70 of the 90 eyes (77.77%) whereas OCTA identified CNV in 69 eyes (76.7%). Among 69 eyes with CNV, it was well-defined in 51 (73.9%) eyes and poorly defined in 18 (26.1%) eyes. There were four false positive and five false negative cases. The sensitivity, specificity, positive predictive value and negative predictive value of OCTA in detection of nAMD were found to be 92.85%, 80.0%, 94.2 and 76.2, respectively. Conclusion OCTA is a useful, noninvasive, reproducible imaging tool for diagnosing, classifying and localizing CNV. The technique has high sensitivity and specificity and can be used reliably in cases where FFA is contraindicated or inconclusive.

Predictors of neovascular activity during neovascular age-related macular degeneration treatment based on optical coherence tomography angiography

The advent of anti-vascular endothelial growth factor (VEGF) therapies has remarkably improved the functional outcomes of neovascular age-related macular degeneration (nAMD) patients. However, there are guidelines on how to start treatment, the guidelines for discontinuing treatment are not yet clear. In this respect, the treat-extend-stop (TES) protocol have showed us the possibility of discontinuing treatment. In this study, we tried to investigate optical coherence tomography angiography (OCTA) biomarkers related to recurrence of neovascular activity in eyes with nAMD undergoing treatment using TES protocol. A total of 134 eyes with nAMD were divided into two groups (stop, non-stop) depending on whether they met criteria for stopping anti-VEGF treatment. Quantitative and qualitative OCTA parameters including the morphologic pattern of choroidal neovascularization (CNV) were compared between groups. Of these, 44 eyes (32.8%) were in the stop group and 90 eyes (67.2%) were in the non-stop group. In multivariate regression analysis, closed-circuit pattern of CNV and the presence of peripheral loop were associated with the non-stop group (all p < 0.001). Our results imply that the morphologic appearance of CNV on OCTA after anti-VEGF treatment may be a useful biomarker to predict weaning from treatment.

Changes in the OCT angiographic appearance of type 1 and type 2 CNV in exudative AMD during anti-VEGF treatment

Objective

Optical coherence tomography angiography (OCT-A) enables detailed visualisation of the vascular structure of choroidal neovascularisation (CNV). The aim of this study was to determine whether mathematically ascertained OCT-A vascular parameters of type 1 and type 2 CNV in exudative age-related macular degeneration (AMD) change during antivascular endothelial growth factor (anti-VEGF) treatment. The OCT-A vascular parameters were also compared with previously obtained activity parameters (fluid distribution on spectral domain OCT (SD-OCT)) to establish whether they could potentially be used as further ‘activity parameters’ for assessment of anti-VEGF treatment.

Methods and Analysis

We evaluated 27 eyes of 27 patients (mean follow-up 9.8 months) with type 1, type 2 or mixed CNV who had received anti-VEGF treatment (IVAN scheme). The parameters analysed were area (aCNV), total length of all vessels (tlCNV), overall number of vascular segments (nsCNV) and fractal dimension (FD) of the CNV. The changes in each of these parameters were correlated with the central foveal thickness (CFT).

Results

Regression and renewed perfusion of the CNV corresponded with the decrease or increase, respectively, of macular fluid distribution on SD-OCT. The increase and decrease of CFT during anti-VEGF treatment were highly significantly correlated with changes in FD (p<0.00001), aCNV (p<0.00001), tlCNV (p<0.00001) and nsCNV (p<0.00001).

Conclusion

OCT-A enables detailed analysis of AMD with regard to FD, aCNV, tlCNV and nsCNV. As the changes in these parameters correlate closely with changes on SD-OCT, they can be used as new activity parameters, alongside fluid distribution, for assessment of treatment effect and as parameters of stabilisation or the need for repeated treatment.

Comparison of Automated versus Manually Modified OCT Angiography En Face Slabs for Detection of Choroidal Neovascularization

PURPOSE

To evaluate the sensitivity and specificity for the detection of choroidal neovascularization (CNV) using automatically generated versus manually modified swept-source OCT angiography (SS-OCTA) en face images.

DESIGN

Prospective cohort study.

PARTICIPANTS

Consecutive patients with various chorioretinal diseases and subretinal hyperreflective material (SHRM) or pigment epithelial detachments (PEDs) on OCT possibly corresponding to CNV in at least 1 eye.

METHODS

A total of 102 eyes of 63 patients were included in this study. Fluorescein angiography (FA) and SS-OCTA imaging (PLEX Elite 9000, Carl Zeiss Meditec, Dublin, CA) were performed at the same day. OCTA en face images were generated using the "retina," "avascular," "choriocapillaris," and "outer retina to choriocapillaris (ORCC)" slabs automatically provided by the software. In addition, a custom slab was created by manual modification of the automatically provided boundary "retinal pigment epithelium fit" positioned at the level of Bruch's membrane and anterior to any SHRM or PED to ensure that a possible CNV was captured in its entirety. Two graders independently evaluated OCTA en face images for the presence of CNV masked to all other images of the patient.

MAIN OUTCOME MEASURES

Sensitivity and specificity for detection of CNV using FA as the reference.

RESULTS

In 40% of cases (41/102), a CNV was detected on FA. Automatically provided OCTA en face slabs revealed the highest sensitivity for the "ORCC" slab (46.3%), followed by the "retina" slab (22.0%), "avascular" slab (17.1%), and "choriocapillaris" slab (14.6%). Specificity ranged between 93.4% for "ORCC" and 100% for the "retina" and "avascular" slabs. Sensitivity could be increased to 78.1% using the custom slab with a specificity of 88.5%. Concordance between FA and OCTA en face slabs was moderate for the "ORCC" slab (κ = 0.43; range, 0.41-0.60) and substantial for the custom slab (κ = 0.67; range, 0.61-0.80).

CONCLUSIONS

Segmentation artifacts and incomplete coverage of CNV on SS-OCTA en face images may impede identification of CNV. Manual modification of the position of automatically generated segmentation lines anterior and posterior to any suspected CNV (SHRM or PED) increases the sensitivity of CNV detection compared with automatically generated slabs.

Appearance of pediatric choroidal neovascular membranes on optical coherence tomography angiography

PURPOSE

Compared with fluorescein angiography (FA), the gold standard for diagnosing choroidal neovascularization (CNV) activity, optical coherence tomography angiography (OCTA) is non-invasive without risks associated with fluorescein dye use, and may be especially advantageous in the diagnosis and monitoring of children with CNV.

METHODS

Eight eyes from eight patients aged 12 months to 18 years were imaged with the investigational Spectralis OCTA (version 6.9, Heidelberg Engineering, Heidelberg, Germany) and the RTVue XR Avanti (Optovue Inc., Fremont, CA, USA). Two patients were imaged during examination under anesthesia while six patients were imaged in the clinic. Demographic information, ocular characteristics, treatment history, and imaging studies (color photos, fluorescein angiography, OCT) were collected and reviewed.

RESULTS

Three eyes had active CNV while five had quiescent CNV at the time of imaging. CNV was idiopathic or secondary to trauma, retinal vascular dysgenesis versus retinopathy of prematurity, pigmentary retinopathy, Best vitelliform macular dystrophy, panuveitis, morning glory disc anomaly, and optic disc drusen. OCTA of two active CNV demonstrated presence of a main trunk with multiple fine capillaries, vessel loops, and anastomoses. OCTA was repeated after treatment for two CNV and demonstrated a decrease in size with loss of fine capillaries, vessel loops, and anastomoses. For the third active CNV, OCTA verified flow in the CNV complex despite the uncertainty of FA hyperfluorescence in the setting of grossly abnormal retinal vasculature. The five quiescent CNV all lacked fine capillaries, vessel loops, and anastomoses on OCTA.

CONCLUSION

OCTA demonstrates morphological differences between active and quiescent pediatric CNV.

Oct angiography compared to fluorescein angiography, indocyanine green angiography and optical coherence tomography in the detection of choroidal neovascularization in pigment epithelial detachment

PURPOSE

To evaluate the agreement between multimodal imaging-MI (fluorescein angiography, indocyanine green angiography, optical coherence tomography) and optical coherence tomography angiography (OCTA) in the detection of choroidal neovascularization (CNV) in patients with pigment epithelial detachment with subretinal/intraretinal fluid (PED+F) compared to patients with PED without subretinal/intraretinal fluid (PED-F).

METHODS

Twenty-two eyes of 15 patients were divided into two groups (PED+F and PED-F). All patients underwent MI and OCTA with manual and automatic segmentation. MI findings were compared to OCTA findings and then analysed.

RESULTS

In the PED+F group (10 eyes), all studied eyes demonstrated CNV in MI. In manual segmentation OCTA assessment, 9 of 10 eyes (90%) were detected with CNV. When evaluated by automatic segmentation, 8 of 10 eyes (80%) revealed the presence of CNV. In the PED-F (12 eyes) group, all eyes did not demonstrate CNV in MI and OCTA evaluations, either by manual or automatic segmentation. The agreement between MI and OCTA shows concordance (k: 0.908; 95% CI, 0.491-1.000); the evaluation of the agreement between the automatic and manual segmentation also shows concordance (k: 0.904; 95% CI, 0.488-1.000).

CONCLUSION

The solid agreement between the multimodal imaging regarding the ability of OCTA to identify possible initial CNV in a patient with PED-F was observed. Accuracy was 95.45%. In addition, the agreement between manual and automatic segmentation to identify CNV on OCTA was also shown.