Fourier-domain optical coherence tomography evaluation of retinal and optic nerve head neovascularisation in proliferative diabetic retinopathy

Early Sign of Retinal Neovascularization Evolution in Diabetic Retinopathy: A Longitudinal OCT Angiography Study

Purpose

To assess whether the combination of en face OCT and OCT angiography (OCTA) can capture observable, but subtle, structural changes that precede clinically evident retinal neovascularization (RNV) in eyes with diabetic retinopathy (DR).

Design

Retrospective, longitudinal study.

Participants

Patients with DR that had at least 2 visits.

Methods

We obtained wide-field OCTA scans of 1 eye from each participant and generated en face OCT, en face OCTA, and cross-sectional OCTA. We identified eyes with RNV sprouts, defined as epiretinal hyperreflective materials on en face OCT with flow signals breaching the internal limiting membrane on the cross-sectional OCTA without recognizable RNV on en face OCTA and RNV fronds, defined as recognizable abnormal vascular structures on the en face OCTA. We examined the corresponding location from follow-up or previous visits for the presence or progression of the RNV.

Main Outcome Measures

The characteristics and longitudinal observation of early signs of RNV.

Results

From 71 eyes, we identified RNV in 20 eyes with the combination of OCT and OCTA, of which 13 (65%) were photographically graded as proliferative DR, 6 (30%) severe nonproliferative DR, and 1 (5%) moderate nonproliferative diabetic retinopathy. From these eyes, we identified 38 RNV sprouts and 26 RNV fronds at the baseline. Thirty-four RNVs (53%) originated from veins, 24 (38%) were from intraretinal microabnormalities, and 6 (9%) were from a nondilated capillary bed. At the final visit, 53 RNV sprouts and 30 RNV fronds were detected. Ten eyes (50%) showed progression, defined as having a new RNV lesion or the development of an RNV frond from an RNV sprout. Four (11%) RNV sprouts developed into RNV fronds with a mean interval of 7.0 months. Nineteen new RNV sprouts developed during the follow-up, whereas no new RNV frond was observed outside an identified RNV sprout. The eyes with progression were of younger age (P = 0.014) and tended to be treatment naive (P = 0.07) compared with eyes without progression.

Conclusions

Longitudinal observation demonstrated that a combination of en face OCT and cross-sectional OCTA can identify an earlier form of RNV before it can be recognized on en face OCTA.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Vitreous hemorrhage in retinal vein occlusion without visible traction from the posterior vitreous membrane: An optical coherence tomography angiography case report study

Background

We report an unusual case of retinal vein occlusion (RVO) associated with vitreous hemorrhage (VH) without visible traction from the posterior vitreous membrane (PVM) at the bleeding point, challenging our current understanding of VH pathophysiology.

Case presentation

A 52-year-old man presented with VH in the right eye. A detailed examination using optical coherence tomography angiography (OCTA) and ultra-widefield fluorescein angiography revealed branch RVO with non-perfused areas (NPAs) extending peripherally and neovascularization elsewhere (NVE). OCTA showed NVE infiltrating the vitreous cavity, leading to substantial bleeding without visible PVM traction at the bleeding point. The NVE was successfully removed following vitrectomy, and visual acuity improved from 20/20 to 20/13 preoperatively, along with a postoperative improvement in floaters.

Conclusions

This unique case of RVO suggests the possibility of VH occurring independent of PVM contractions at the bleeding point, challenging the traditional understanding of VH. This finding underscores the potential role of OCTA in diagnosing and managing retinal vascular diseases, underscoring the need for further investigations into the underlying mechanisms, with potential implications for personalized therapeutic strategies.

Interest of Widefield-Optical Coherence Tomography Angiography for Diagnosis and Follow-Up of Retinal Neovascularisation in Proliferative Diabetic Retinopathy

Aim

The primary aim was to evaluate the use of optical coherence tomography angiography (OCTA) versus fluorescein angiography (FA) for detecting and monitoring retinal neovascularization (NV) in patients with proliferative diabetic retinopathy (PDR) receiving treatment with anti-vascular endothelial growth factor (anti-VEGF).

Methods

Treatment-naïve patients with PDR, willing to begin anti-VEGF treatment without laser from 9/2018–2/2020 were included. FA and OCTA scans were obtained at baseline, and a second OCTA scan was performed after 6 months of anti-VEGF therapy. We calculated sensitivity and specificity for two masked graders with respect to identifying NV on OCTA versus FA. Using ImageJ software, we also measured the change in NV size, at baseline and 6-month follow-up.

Results

Ten eyes in eight patients were included, of which three eyes in three patients received a 6-month follow-up examination. Mean age was 51.7 ± 11.2 years, and 75% of patients were male. Overall, 21 NV sites in the 10 eyes were identified both clinically and on FA. Using OCTA scans, the sensitivity and specificity for both graders were extremely high, ranging from 95.2% to 100%. At 6-month follow-up, NV size decreased by 69.8%.

Conclusion

These results suggest that OCTA may provide a suitable alternative to FA for visualizing, measuring, and monitoring changes in retinal NV in patients with PDR who receive anti-VEGF therapy.

Utilisation of optical coherence tomography and optical coherence tomography angiography to assess retinal neovascularisation in diabetic retinopathy

PURPOSE

To evaluate the use of optical coherence tomography angiography (OCTA), structural OCT and fundus fluorescein angiography (FFA) to distinguish neovascularisation elsewhere (NVE) from intra retinal microvascular abnormalities (IRMA) and their use in early detection and possible risk assessment for vitreous haemorrhage.

METHODS

A cross-sectional study of a consecutive series of patients with suspected NVE and IRMA using clinical examination and FFA, were examined further with OCT and OCTA. Treated and untreated eyes were also compared.

RESULTS

Images from 33 eyes of 26 patients, showed 27 NVE and 14 IRMA lesions based on clinical examination +/- FFA. Lesions were re-classified as NVE in 22 eyes. Ten eyes had received past treatment. In all 10 treated eyes, vascular flow and vitreous connection were found but not FFA leakage. In 18/22 eyes with NVE there was a breach of the internal limiting membrane (ILM), in 4 eyes there was FFA leak, ILM outpouching but no breach. In two eyes, NVE originated from sea fan IRMA. Ten eyes images were classified as IRMA only with no FFA leak, or ILM breach. The relation of pre-retinal NVE to the vitreous can be visualised.

CONCLUSION

Lesions, considered to be NVE, after further assessment with OCT and OCTA, can be intra-retinal, with ILM disruption but no ILM breach and leakage on FFA. ILM disruption maybe one of the earliest signs of the development of neovascularisation. Visualisation of the relation to the posterior vitreous is likely to be useful in assessing risk of vitreous haemorrhage.

Update on Optical Coherence Tomography and Optical Coherence Tomography Angiography Imaging in Proliferative Diabetic Retinopathy

Proliferative diabetic retinopathy (PDR) is a major cause of blindness in diabetic individuals. Optical coherence tomography (OCT) and OCT-angiography (OCTA) are noninvasive imaging techniques useful for the diagnosis and assessment of PDR. We aim to review several recent developments using OCT and discuss their present and potential future applications in the clinical setting. An electronic database search was performed so as to include all studies assessing OCT and/or OCTA findings in PDR patients published from 1 January 2020 to 31 May 2021. Thirty studies were included, and the most recently published data essentially focused on the higher detection rate of neovascularization obtained with widefield-OCT and/or OCTA (WF-OCT/OCTA) and on the increasing quality of retinal imaging with quality levels non-inferior to widefield-fluorescein angiography (WF-FA). There were also significant developments in the study of retinal nonperfusion areas (NPAs) using these techniques and research on the impact of PDR treatment on NPAs and on vascular density. It is becoming increasingly clear that it is critical to use adequate imaging protocols focused on optimized segmentation and maximized imaged retinal area, with ongoing technological development through artificial intelligence and deep learning. These latest findings emphasize the growing applicability and role of noninvasive imaging in managing PDR with the added benefit of avoiding the repetition of invasive conventional FA.

Characterizing Flow and Structure of Diabetic Retinal Neovascularization after Intravitreal Anti-VEGF Using Optical Coherence Tomography Angiography: A Pilot Study

Background/Aims. This study evaluates changes of flow and structure of diabetic retinal neovascularization (NV) treated with intravitreal antivascular endothelial growth factor (VEGF) agents using optical coherence tomography angiography (OCTA). With OCTA, retinal blood vessels are visualized at high resolution to separately look at flow and structure information without the need for dye injection. We introduce a new measurement method including and combining information of flow and structure. Methods. Retrospective observational case series. Patients with proliferative diabetic retinopathy (PDR) were treated with intravitreal antiVEGF injections. Retinal NV were repeatedly imaged using swept-source OCTA (Zeiss PlexElite 9000) at baseline, after initial treatment block with 3-4 monthly injections, and during a follow-up period of up to 51 weeks. Change of size and flow density of the structural and angio area of NV was assessed. Results. Nine NV in eight eyes of five patients were analyzed with a median follow-up time of 45 weeks. After the initial treatment block, en face structural area regressed, 18.7% ± 39.0% (95% CI 44.2–6.8%, p=0.26), and en face angio area regressed, 51.9% ± 29.5% (95% CI 32.6 to 71.2%, p=0.007). Flow density within the en face structural area decreased by 33% ± 19.2% (95% CI 20.5–45.5%, p=0.0077). Flow density within the en face angio area decreased by mean 17.9% ± 25.2% (95% CI 1.4–34.4%, p=0.066). In two fellow eyes, NV recurrence could be observed before the onset of vitreous bleeding in one. Conclusion. Our study introduces a new quantitative measurement for NV in PDR, combining structure and flow measurement. The structure area remained after treatment, while its flow density and angio area regressed. We propose this measurement method as a more physiological and possibly more comparable metrics.

Near-infrared reflectance imaging of neovascularization in proliferative diabetic retinopathy

Background

Blood is one of the main absorbers in the near-infrared spectrum and thus retinal vessels appear dark in near-infrared reflectance (NIR) images. Proliferative diabetic retinopathy (PDR) is characterized by abnormal neovascularization which also absorbs light and appears dark against a lighter fundus background. We analyzed neovascularization in PDR using NIR imaging, by observing changes in the neovascular complexes (NVCs) contrast and reflectivity over time.

Methods

Retrospective case series of 20 eyes of 17 patients with PDR who underwent NIR imaging with optical coherence tomography (OCT) using the Spectralis System. NVCs presence and activity was determined using clinical, tomographic and angiographic criteria. At baseline, all NVCs were qualitatively graded in the NIR image into 3 groups (absent, present and inactive and present and active) and their evolution over time was registered as progression, regression or same status.

Results

Twenty-seven NVCs were imaged, of which, 52% were neovascularization of the disc (NVD) and 48% were elsewhere (NVE). Consecutive NIR images were obtained from baseline to up to 5 time-points with a mean follow-up of 3.2 ± 1.7 years. All eyes underwent laser treatment and 30% had additional intravitreal therapy. Using NIR imaging, NVCs were classified at baseline as absent, present and inactive and present and active, respectively in 11, 4 and 85% of cases. NIR identified active neovascularization as hyporeflective irregular dark vessels originating from the retinal venules in NVE or from the disc in NVD. In all groups during follow-up, progression was identified as the development of new vascular hyporeflective dark fronds while regression was shown by reduced dark perfusion. Five eyes developed a wolf’s jaw configuration with vascular hyporeflective new vessels and hyperreflective tissue from extensive fibrosis. Fibrosis was more apparent in later images, reaching 86%. In 3 cases (11%), the NVC was no longer seen in NIR, although was still identifiable on OCT over the NVC area.

Conclusions

NIR is a non-invasive imaging modality commonly performed alongside OCT and frequently overlooked which can be useful to evaluate NVCs in PDR. Changes in NVC contrast and reflectivity due to blood perfusion can help in the detection and monitoring of diabetic proliferative disease and aid clinicians in daily practice.

Optical Coherence Tomography Angiography Features of Neovascularization in Proliferative Diabetic Retinopathy

Purpose

To describe features of neovascularization in proliferative diabetic retinopathy (PDR) using optical coherence tomography angiography (OCTA).

Methods

A retrospective case series was performed in 23 eyes from 21 patients who underwent OCTA of neovascular complexes (NVCs) due to PDR. Eyes were imaged with the DRI Triton swept-source OCTA, Avanti RTVue XR or Cirrus HD-OCT 5000 as part of routine clinical examination. Segmentation was adjusted to include vasculature between the vitreous cavity and the internal limiting membrane (ILM). The presence of NVCs was confirmed by clinical examination and multimodal imaging such as color or red-free fundus photography, fluorescein angiography, multicolor imaging or near-infrared reflectance.

Results

Thirty-five NVCs were imaged, of which, 34% were neovascularization of the disc (NVD) and 66% were neovascularization elsewhere (NVE). On structural OCT B-scans, NVE appeared as medium to highly reflective tissue that breached the ILM, while NVD showed highly reflective tissue protruding from the disc in a sea fan configuration. Flow signal was seen on OCTA in all cases of NVE and in 67% of NVD lesions. Areas with minimal or absent retinal flow signal identified retinal nonperfusion areas and were found adjacent to 87% of NVE. Intraretinal microvascular abnormalities (IRMAs) were noted next to 70% of NVE. Absent flow signal was seen in 4 NVD cases showing posterior shadowing and were considered inactive.

Conclusion

OCTA appears useful for imaging NVCs, IRMAs, and retinal nonperfusion areas in eyes with diabetic retinopathy. This imaging modality enables noninvasive screening and monitoring of PDR and can obviate the need for additional testing in certain clinical settings.

Swept-source optical coherence tomography angiography vitreo-retinal segmentation in proliferative diabetic retinopathy

PURPOSE

To identify a new cortical vitreous segmentation protocol for non invasive standardised investigation of Neovascularisation (NV) with detection of regression of NV activity in Proliferative Diabetic Retinopathy (PDR).

DESIGN

Retrospective study.

PARTICIPANTS

One hundred and eighty-six eyes of 93 consecutive diabetic patients (mean age: 52.6 ± 11.0 years) imaged using Topcon Triton^® Swept-Source Optical Coherence Tomography Angiography (SS-OCTA) from June 2015 to January 2017.

METHODS

Scans were performed through the macula, optic disc and areas of possible NV in mid-peripheral retina using 6 × 6 mm and/or 9 × 9 mm raster-patterns in three segmentation protocols: Vitreo-Retinal (VRS), Outer-Vitreous (OVS) and Core-Vitreous Segmentation (CVS). Any suspicion of PDR was confirmed in all patients by Heidelberg^® Widefield-Fundus-Fluorescein-Angiography (WF-FFA) and/or Optos^® Ultra-WF-FFA (UWF-FFA). Inter-observer reproducibility of NV diagnosis and agreement between SS-OCTA and UWF-FFA were assessed. Primary outcome was the identification of an effective and reproducible segmentation protocol. Secondary outcome was the identification of NV regression after treatment.

RESULTS

Sensitivity-specificity reached, respectively, the value of 100 to 100 in detecting NVD, and 96.6 to 100 in detecting NVE in compared areas. SS-OCTA was able to confirm absence of blood flow within the residual NV plexus when using VRS protocol in 30 eyes in which regression of NV with absence of leakage was documented on FFA.

CONCLUSION

Three segmentation protocols (VRS, OVS and CVS) with different but complementary characteristics, allowed a reproducible and standardised investigation of NVD and NVE. The proposed new SS-OCTA cortical vitreous segmentation protocols may be of value when identifying and assessing NV-activity (VRS, OVS and CVS) or NV-regression (VRS) in PDR and therefore, response to therapy.

Optical coherence tomography features of neovascularization in proliferative diabetic retinopathy: a systematic review

Background

Diabetic retinopathy (DR) is a leading cause of blindness due to diabetic macular edema (DME) or complications of proliferative diabetic retinopathy (PDR). Optical coherence tomography (OCT) is a noninvasive imaging technique well established for DME but less used to assess neovascularization in PDR. Developments in OCT imaging and the introduction of OCT angiography (OCTA) have shown significant potential in PDR.

Objectives

To describe the tomographic features of PDR, namely of neovascularization, both of the optic disc (NVD) and elsewhere (NVE), intraretinal microvascular abnormalities (IRMA), retinal nonperfusion areas (NPA), status of the posterior vitreous, vitreoschisis and vitreous and subhyaloid/sub-ILM hemorrhages.

Data sources

Electronic database search on PubMed and EMBASE, last run on December 19th 2019.

Study eligibility criteria, participants and interventions

Publications assessing OCT and/or OCTA findings in PDR patients. All study designs were allowed except for case-reports, conference proceedings and letters.

Study appraisal

Newcastle–Ottawa Scale for observational studies was used for purposes of risk of bias assessment.

Results

From the 1300 studies identified, 283 proceeded to full-text assessment and 60 were included in this comprehensive review. OCT was useful in detecting NVD and NVE, such as in characterizing disease activity and response to laser and/or anti-VEGF therapies. The absence of posterior vitreous detachment seemed determinant for neovascular growth, with the posterior hyaloid acting as a scaffold. OCTA allowed a more detailed characterization of the neovascular complexes, associated NPA and disease activity, allowing the quantification of neovessel area and flow index. However, changes in OCTA blood flow signal following local therapies did not necessarily correlate with structural regression. Widefield and ultra-widefield OCTA were highly sensitive in the detection of PDR, adding value to disease staging and monitoring. Compared to fluorescein angiography, OCTA was more sensitive in detecting microvascular changes indicating disease progression.

Limitations

Publication languages were restricted. Most included studies were observational and non-comparative. Risk of bias regarding case representativeness.

Conclusions

OCT-based retinal imaging technologies are advancing rapidly and the trend is to be noninvasive and wide-field. OCT has proven invaluable in diagnosing, staging and management of proliferative diabetic disease with daily application in clinical and surgical practices.

Wide-field optical coherence tomography angiography for the detection of proliferative diabetic retinopathy

PURPOSE

To compare the ability of wide-field optical coherence tomography angiography (WF-OCTA) to that of ultra-wide field fluorescein angiography (UWF-FA) and ultra-wide-field color fundus photography (UWF-CP) to detect retinal neovascularization (NV) in eyes with proliferative diabetic retinopathy (PDR).

METHODS

In this cross-sectional study, naïve patients with active PDR underwent UWF-FA and UWF-CP using the Optos 200Tx and WF-OCTA with 12 × 12 mm fields of five visual fixations using the PLEX Elite 9000. NV was defined on OCTA when the co-registered B-scan with flow overlay of the vitreoretinal interface (VRI) segmentation showed extraretinal proliferation. Three masked readers examined the UWF-FA, UWF-CP, and WF-OCTA independently for the presence of NV. Statistical analysis was performed to compare the diagnostic accuracy of the 3 wide-field imaging modalities using OCT B-scan as the reference standard.

RESULTS

In 82 eyes with PDR, neovascularization of the disc (NVD) was detected in 13 eyes by UWF-CP, 35 eyes with UWF-FA, and 37 eyes with OCTA using the VRI slab. Upon review of the 2500 OCT B-scans with superimposed flow overlay of each eye, NVD was confirmed in 37 eyes. The sensitivity and specificity of NVD detection were 35.1% and 97.8%, respectively for UWF-CP; 94.6% and 100%, respectively, for UWF-FA; and 100% and 100% for WF-OCTA. One hundred ninety-six foci of neovascularization elsewhere (NVE) were identified with the OCT B-scan with superimposed flow overlay. UWF-CP analysis was able to detect 62 foci of NVE of the 196 confirmed by B-scan (31.6% detection rate). An additional 11 foci of NVE seen on UWF-CP were not confirmed by B-Scan (15% false positive rate). There were 182 foci of NVE identified by UWF-FA (detection rate 91.3%), while WF-OCTA detected 196 retinal NVEs (detection rate 100%). The rate of false positives for both UWF-FA and WF-OCTA was low (< 2%).

CONCLUSION

WF-OCTA can identify NV that is not evident in UWF-CP and represents a faster and safer alternative to UWF-FA for surveillance of PDR with comparable diagnostic accuracy.

[On classification of diabetic retinopathy]

The article analyses current state of the problem of diabetic retinopathy classifications based on the data from Russian and foreign literature on pathogenesis, clinical manifestations, results of multicenter studies on treatment and prognosis of the disease. Every existing classification was found to be limited in applications; attempts had been made to unify and complement them with the aim of achieving more complete and better-detailed description of the processes of diagnostics and determination of treatment algorithms. In conclusion, none of the existing classifications can be considered consistent in both clinical and practical aspects with respect to diabetic retinopathy.

"For Mass Eye and Ear Special Issue" Adaptive Optics in the Evaluation of Diabetic Retinopathy

Retinal imaging is a fundamental tool for clinical and research efforts in the evaluation and management of diabetic retinopathy. Adaptive optics (AO) is an imaging technique that enables correction of over 90% of the optical aberrations of an individual eye induced primarily by the tear film, cornea and lens. The two major tasks of any AO system are to measure the optical imperfections of the eye and to then compensate for these aberrations to generate a corrected wavefront of reflected light from the eye. AO scanning laser ophthalmoscopy (AOSLO) provides a theoretical lateral resolution limit of 1.4 μm, allowing the study of microscopic features of the retinal vascular and neural tissue. AOSLO studies have revealed irregularities of the photoreceptor mosaic, vascular loss, and details of vascular lesions in diabetic eyes that may provide new insight into development, regression, and response to therapy of diabetic eye disease.

Application of optical coherence tomography angiography in diabetic retinopathy: a comprehensive review

Optical coherence tomography angiography (OCTA) is a noninvasive method that enables visualization of blood flow within retinal vessels down to the size of capillaries by detecting motion contrast from moving blood cells. OCTA provides a fast and safe procedure to assess retinal microvasculature with higher contrast and resolution than conventional fluorescence angiography. The different capillary plexuses are displayed separately and their perfusion density can be quantified. Imaging capabilities such as these have led to an emerging field of clinical application for OCTA in vascular diseases such as diabetic retinopathy (DR). Evaluation of parameters such as parafoveal capillary perfusion density could be a biomarker for disease diagnosis and progression. Typical microvascular changes in DR such as capillary nonperfusion, microaneurysms, intraretinal microvascular abnormalities, and neovascularization can be reliably detected in optical coherence tomography angiograms, characterized in detail and attributed to the different capillary plexuses. Monitoring of these lesions in vivo gives potential novel insight into the pathophysiology in DR. The aim of this article is to summarize the potential applications/utility of OCTA in DR reported in the literature.

Characteristics of Neovascularization in Early Stages of Proliferative Diabetic Retinopathy by Optical Coherence Tomography Angiography

PURPOSE

To classify retinal neovascularization in untreated early stages of proliferative diabetic retinopathy (PDR) based on optical coherence tomography angiography (OCTA).

DESIGN

A cross-sectional study.

METHODS

Thirty-five eyes were included. They underwent color fundus photography, fluorescein angiography (FA), and OCTA examinations. Neovascularizations elsewhere (NVEs), neovascularizations at the disc (NVDs), and intraretinal microvascular abnormalities (IRMAs) were scanned by OCTA. The origin and morphology of NVE/NVD/IRMA on OCTA were evaluated. Retinal nonperfusion areas (NPAs) were measured using ImageJ software.

RESULTS

In 35 eyes successfully imaged, 75 NVEs, 35 NVDs, and 12 IRMAs were captured. Three proposed subtypes of NVE were identified based on the origins and morphologic features. Type 1 (32 of 75, 42.67%) originated from the venous side, in a tree-like shape. Type 2 (30 of 75, 40.00%) originated from capillary networks, with an octopus-like appearance. Type 3 (13 of 75, 17.33%) originated from the IRMAs, having a sea fan shape. NVD originated from the retinal artery, from the retinal vein, or from the choroid, and arose from the bending vessels near the rim of the optic disc. IRMA originated from and drained into retinal venules, extending into the retina. The initial layer and affiliated NPA were significantly different in the 3 subtypes of NVEs (all P < .01).

CONCLUSIONS

OCTA allowed identification of the origins and morphologic patterns of neovascularization in PDR. The new classification of retinal neovascularization may be useful to better understand pathophysiological mechanisms and to guide efficient therapeutic strategies.

Characterization of In Vivo Retinal Lesions of Diabetic Retinopathy Using Adaptive Optics Scanning Laser Ophthalmoscopy

PURPOSE

To characterize hallmark diabetic retinopathy (DR) lesions utilizing adaptive optics scanning laser ophthalmoscopy (AOSLO) and to compare AOSLO findings with those on standard imaging techniques.

METHODS

Cross-sectional study including 35 eyes of 34 study participants. AOSLO confocal and multiply scattered light (MSL) imaging were performed in eyes with DR. Color fundus photographs (CF), infrared images of the macula (Spectralis, Heidelberg), and Spectralis spectral domain optical coherence tomography SDOCT B-scans of each lesion were obtained and registered to corresponding AOSLO images.

MAIN OUTCOME MEASURES

Individual lesion characterization by AOSLO imaging. AOSLO appearance was compared with CF and SDOCT imaging.

RESULTS

Characterized lesions encompassed 52 microaneurysms (MA), 20 intraretinal microvascular abnormalities (IRMA), 7 neovascularization (NV), 11 hard exudates (HE), 5 dot/blot hemorrhages (HEM), 4 cotton wool spots (CWS), and 14 intraretinal cysts. AOSLO allowed assessment of perfusion in vascular lesions and enabled the identification of vascular lesions that could not be visualized on CF or SDOCT.

CONCLUSIONS

AOSLO imaging provides detailed, noninvasive in vivo visualization of DR lesions enhancing the assessment of morphological characteristics. These unique AOSLO attributes may enable new insights into the pathological changes of DR in response to disease onset, development, regression, and response to therapy.

Morphological differences between optic disc collaterals and neovascularization on optical coherence tomography angiography

BACKGROUND

To study morphological features of optic disc venous collaterals (OVCs) and neovascularization of optic disc (NVD) on optical coherence tomography angiography (OCTA).

METHODS

Patients with OVCs and NVDs secondary to ischemic retinal diseases were prospectively enrolled. Multimodal imaging was performed using color fundus photography, fluorescein angiography (FA), and OCTA. Morphological evaluation of en-face structural OCT, cross-sectional and en-face OCTA was performed.

RESULTS

Twenty eyes (20 patients; OVCs: n = 10 and NVD: n = 10) were included. OVCs appeared as small, loopy vessels distinct from surrounding peripapillary capillaries on OCTA in the radial peripapillary capillary frame. NVDs appeared as a mesh of fine caliber, raised vessels best seen in the vitreous slab of OCTA. Flow signals in these vascular alterations correlated well with hyperfluorescence on FA.

CONCLUSIONS

OCTA provides improved visualization of NVDs and OVCs in ischemic retinal diseases such as diabetic retinopathy and retinal vein occlusions compared to conventional FA.

Evaluation of Preretinal Neovascularization in Proliferative Diabetic Retinopathy Using Optical Coherence Tomography Angiography

BACKGROUND AND OBJECTIVE

To describe a method for visualizing preretinal neovascularization in proliferative diabetic retinopathy (PDR) using optical coherence tomography angiography (OCTA) and report the findings in the surrounding vasculature.

PATIENTS AND METHODS

Patients with PDR diagnosed on clinical examination who received OCTA scans using the RTVue XR Avanti (Optovue, Fremont, CA) were evaluated. To visualize preretinal neovascularization, OCT angiograms were segmented to project vasculature above the internal limiting membrane (ILM). OCT angiograms were segmented between the ILM and Bruch's membrane to show adjacent retinal vasculature.

RESULTS

Thirteen eyes were determined to have preretinal neovascularization in the posterior pole based on OCTA. One OCT angiogram was not of sufficient quality and thus was eliminated from further study. Eleven eyes (92%) had neovascularization adjacent to retinal capillary nonperfusion and six (50%) were adjacent to intraretinal microvascular abnormalities (IRMAs).

CONCLUSION

OCTA provided high-resolution, depth-resolved blood flow information, allowing for visualization of preretinal neovascularization, IRMA, and adjacent capillary nonperfusion.

Wide-field optical coherence tomography based microangiography for retinal imaging

Optical coherence tomography angiography (OCTA) allows for the evaluation of functional retinal vascular networks without a need for contrast dyes. For sophisticated monitoring and diagnosis of retinal diseases, OCTA capable of providing wide-field and high definition images of retinal vasculature in a single image is desirable. We report OCTA with motion tracking through an auxiliary real-time line scan ophthalmoscope that is clinically feasible to image functional retinal vasculature in patients, with a coverage of more than 60 degrees of retina while still maintaining high definition and resolution. We demonstrate six illustrative cases with unprecedented details of vascular involvement in retinal diseases. In each case, OCTA yields images of the normal and diseased microvasculature at all levels of the retina, with higher resolution than observed with fluorescein angiography. Wide-field OCTA technology will be an important next step in augmenting the utility of OCT technology in clinical practice.

Prediction of regression of retinal neovascularisation after panretinal photocoagulation for proliferative diabetic retinopathy

PURPOSE

The purpose of this study was to evaluate the regression of neovascularization elsewhere (NVE) after panretinal photocoagulation (PRP) based on its location in relation to the internal limiting membrane (ILM).

METHODS

Participants in this retrospective case series were 47 patients with active NVE within the vascular arcade. All patients were treated with PRP and followed up for at least 12 months. The time to regression of NVE based on its location relative to the ILM on spectral domain-optical coherence tomography (SD-OCT) was analyzed.

RESULTS

The proportion of eyes, showing regression of NVE at the end of follow-up period was 19/25 (76 %) in the "below ILM" group and 13/22 (59 %) in the "above ILM" group. The "below ILM" group was associated with a twofold enhanced regression of NVE in comparison to the "above ILM" group (HR = 2.13, p = 0.038).

CONCLUSIONS

Regression of NVE is determined by its location relative to the ILM. Patients with "below ILM" NVE were found to show a twofold increased regression rate in comparison with the "above ILM" group, while the proportion of eyes showing regression of NVE at the end of the follow-up period was significantly greater in the "below ILM" than the "above ILM" group.

En-face optical coherence tomography angiography of neovascularization elsewhere in hemicentral retinal vein occlusion

Purpose

To evaluate how the growth of neovascularization elsewhere (NVE) was delineated in an eye with hemicentral retinal vein occlusion (CRVO) using optical coherence tomography (OCT) angiography.

Patients and methods

We examined a 64-year-old man diagnosed with hemi-CRVO. The area around the occluded vein was scanned using a spectral-domain OCT device (RTVue XR Avanti). Blood flow was detected using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Color fundus photography, fluorescein angiography (FA), and OCT angiography examinations were performed at the first visit and at 3 and 6 months postpresentation.

Results

At the first visit, FA revealed delayed retinal venous filling and extensive areas of capillary nonperfusion. The patient underwent a trial of intravitreal ranibizumab injection (0.5 mg/0.05 mL) for the treatment of macular edema. At 3 months postpresentation, there was no NVE around the occluded vein in the en-face SSADA image, but at 6 months, NVE appeared on the occluded veins. The en-face SSADA image showed the NVE structure in the fibrovascular membrane on the occluded vein more clearly than FA images.

Conclusion

OCT angiography clearly visualized the sprouting of NVE in an eye with hemi-CRVO. New findings of the vascular structure of NVE in hemi-CRVO were revealed using the en-face SSADA algorithm.

Three-dimensional vascular imaging of proliferative diabetic retinopathy by Doppler optical coherence tomography

PURPOSE

To evaluate the 3-dimensional architecture of neovascularization in proliferative diabetic retinopathy using Doppler optical coherence tomography (OCT).

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

Seventeen eyes of 14 patients with proliferative diabetic retinopathy were prospectively studied. Prototype Doppler OCT was used to evaluate the 3-dimensional vascular architecture at vitreoretinal adhesions.

RESULTS

Proliferative membranes were detected in all eyes with proliferative diabetic retinopathy by standard OCT images. Doppler OCT images detected blood flow by neovascularization of the disc in 12 eyes and neovascularization elsewhere in 11 eyes. Doppler OCT images showed the 3-dimensional extent of new vessels at various stages of neovascularization, and the extent of new vessels could be clearly confirmed at vitreoretinal adhesions.

CONCLUSIONS

Doppler OCT is useful for the detection and evaluation of the 3-dimensional vascular structure of neovascularization, and can assist in the noninvasive assessment of proliferative diabetic retinopathy.

Reevaluating the definition of intraretinal microvascular abnormalities and neovascularization elsewhere in diabetic retinopathy using optical coherence tomography and fluorescein angiography

PURPOSE

To evaluate the agreement between clinical examination, spectral-domain ocular coherence tomography (SD OCT), and fluorescein angiography (FA) in diagnosing intraretinal microvascular abnormality (IRMA) and neovascularization elsewhere (NVE) and define the SD OCT features that differentiate NVEs from IRMAs.

DESIGN

Retrospective study.

METHODS

Data were collected from 23 lesions from 8 diabetic patients, seen from July 2012 through October 2013 at Moorfields Eye Hospital, United Kingdom. Main outcomes were SD OCT features and FA leakage of IRMA and neovascular complex. The agreement between 3 evaluations was analyzed by Fleiss' kappa.

RESULTS

The following 5 SD OCT features significantly differentiated IRMAs from NVEs: (1) hyperreflective dots in superficial inner retina (P = .002); (2) the outpouching of internal limiting membrane (ILM) (P = .004); (3) the breach of ILM (P = .004); (4) the breach of posterior hyaloid (P = .0005); (5) hyperreflective dots in vitreous (P = .008). The agreement was moderate between 3 evaluations (κ = 0.48, P = 7.11 × 10(-5)) but substantial between clinical and SD OCT evaluation (κ = 0.72, P = .00055). There was no significant agreement between OCT evaluation and FA leakage (κ = 0.249, P = .232).

CONCLUSIONS

SD OCT will be a valuable adjunct in evaluating IRMA and NVE, since it can verify the histopathologic correlate. SD OCT provides subtle anatomic insights and may be more accurate than clinical examination or leakage on FA, our current method of diagnosing this important endpoint, which has implications in future trial design for proliferative diabetic retinopathy prevention.