Faculty Bibliography

PURPOSE/OBJECTIVE:To develop a consensus nomenclature for reporting optical coherence tomography angiography (OCTA) findings in retinal vascular disease (e.g., diabetic retinopathy, retinal vein occlusion) by international experts. DESIGN/METHODS:Delphi-based survey SUBJECTS, PARTICIPANTS AND/OR CONTROLS: Twenty-five retinal vascular disease and OCTA imaging experts METHODS, INTERVENTION, OR TESTING: A Delphi method of consensus development was used, comprising two rounds of online questionnaires, followed by a face-to-face meeting conducted virtually. Twenty-five experts in retinal vascular disease and retinal OCTA imaging were selected to constitute the OCTA Nomenclature in Delphi Study Group for retinal vascular disease. The four main areas of consensus were: definition of parameters of "widefield (WF)" OCTA, measurement of decreased vascular flow on conventional and WF-OCTA, nomenclature of OCTA findings, and OCTA in retinal vascular disease management and staging. The study endpoint was defined by the degree of consensus for each question: "strong consensus" was defined as ≥ 85% agreement, "consensus" as 80-84% and "near consensus" as 70-79%. MAIN OUTCOME MEASURES/METHODS:Consensus and near-consensus on OCTA nomenclature in retinal vascular disease RESULTS: A consensus was reached that a meaningful change in percentage of flow on WF-OCTA imaging should be an increase or decrease ≥30% of the absolute imaged area of flow signal and that a "large area" of WF-OCTA reduced flow signal should also be defined as ≥ 30% of absolute imaged area. The presence of new vessels (NV) and intra-retinal microvascular abnormalities (IRMAs), the foveal avascular zone (FAZ) parameters, the presence and amount of "no flow" area and the assessment of vessel density in various retinal layers should be added for the staging and classification of DR. Decreased flow ≥ 30% of the absolute imaged area should define an ischemic central retinal vein occlusion (CRVO). Several other items did not meet consensus requirements or were rejected in the final discussion round. CONCLUSIONS:This study provides international consensus recommendations for reporting OCTA findings in retinal vascular disease, which may help to improve the interpretability and description in clinic and clinical trials. Further validation in these settings is warranted and ongoing. Efforts are continuing to address unresolved questions.

Non-exudative macular and choroidal neovascularization (MNV and CNV) usually refers to the entity of treatment-naïve type 1 neovascularization in the absence of associated signs of exudation. Histopathological studies, dating back in the early 70s, identified the presence of non-exudative MNV, but the first clinical report of this finding was in the late 90s using indocyanine green angiography in eyes with age-related macular degeneration (AMD). With more advanced retinal imaging, there has been an ever increasing appreciation of non-exudative MNV associated with AMD and CNV with other macular disorders. However, consensus regarding the exact definition and the clinical management of this entity is lacking. Furthermore, there may be variation in the imaging features and clinical course suggesting that a spectrum of disease may exist. Herein, we review the large body of published work that has provided a better understanding of non-exudative MNV and CNV in the last decade. The prevalence, multimodal imaging features, clinical course, and response to treatment are discussed to elucidate further key insights about this entity. Based on these observations, this review also proposes a new theory about the origin and course of different sub-types of non-exudative MNV/CNV which can have different etiologies and pathways according to the clinical context of disease.

Imaging is an integral part of the evaluation and management of retinal disorders. Each imaging modality has its own unique capabilities and can show a different aspect or perspective of disease. Multimodal retinal imaging provides a wealth of substantive and insightful information; however, the integration of all this complex data can be overwhelming. We discuss the applications and the strengths and limitations of the many different retinal imaging tools that are approved for clinical use. These modalities include color fundus photography, widefield imaging, fundus autofluorescence, near infrared reflectance, optical coherence tomography angiography, and en face optical coherence tomography. We also cover the advantages and disadvantages of a multimodal approach.

PURPOSE/OBJECTIVE:To characterize relationships between Consensus on Neovascular Age-Related Macular Degeneration Nomenclature (CONAN) Study Group classifications of macular neovascularization (MNV) and visual responses to ranibizumab in patients with neovascular age-related macular degeneration (nAMD). METHODS:This was a post hoc analysis of the phase 3 HARBOR trial of ranibizumab in nAMD. Analyses included ranibizumab-treated eyes with baseline multimodal imaging data; baseline MNV; subretinal and/or intraretinal fluid at screening, baseline, or week 1; and spectral-domain optical coherence tomography images through month 24 (n = 700). Mean best-corrected visual acuity (BCVA) over time and mean BCVA change at months 12 and 24 were compared between eyes with type 1, type 2/mixed type 1 and 2 (type 2/M), and any type 3 MNV at baseline. RESULTS:At baseline, 263 (37.6%), 287 (41.0%), and 150 (21.4%) eyes had type 1, type 2/M, and any type 3 lesions, respectively. Type 1 eyes had the best mean BCVA at baseline (59.0 [95% CI: 57.7-60.3] letters) and month 24 (67.7 [65.8-69.6] letters), whereas type 2/M eyes had the worst (50.0 [48.6-51.4] letters and 60.8 [58.7-62.9] letters, respectively). Mean BCVA gains at month 24 were most pronounced for type 2/M eyes (10.8 [8.9-12.7] letters) and similar for type 1 (8.7 [6.9-10.5] letters) and any type 3 eyes (8.3 [6.3-10.3] letters). CONCLUSION/CONCLUSIONS:Differences in BCVA outcomes between CONAN lesion type subgroups support the use of an anatomic classification system to characterize MNV and prognosticate visual responses to anti-vascular endothelial growth factor therapy for nAMD. TRIAL REGISTRATION/BACKGROUND:ClinicalTrials.gov identifier: NCT00891735. Date of registration: April 29, 2009.

Purpose/UNASSIGNED:To develop a machine-learning image processing model for three-dimensional (3D) reconstruction of vitreous anatomy visualized with swept-source optical coherence tomography (SS-OCT). Methods/UNASSIGNED:Healthy subjects were imaged with SS-OCT. Scans of sufficient quality were transferred into the Fiji is just ImageJ image processing toolkit, and proportions of the resulting stacks were adjusted to form cubic voxels. Image-averaging and Trainable Weka Segmentation using Sobel and variance edge detection and directional membrane projections filters were used to enhance and interpret the signals from vitreous gel, liquid spaces within the vitreous, and interfaces between the former. Two classes were defined: "Septa" and "Other." Pixels were selected and added to each class to train the classifier. Results were generated as a probability map. Thresholding was performed to remove pixels that were classified with low confidence. Volume rendering was performed with TomViz. Results/UNASSIGNED:Forty-seven eyes of 34 healthy subjects were imaged with SS-OCT. Thirty-four cube scans from 25 subjects were of sufficient quality for volume rendering. Clinically relevant vitreous features including the premacular bursa, area of Martegiani, and prevascular vitreous fissures and cisterns, as well as varying degrees of vitreous degeneration were visualized in 3D. Conclusions/UNASSIGNED:A machine-learning model for 3D vitreous reconstruction of SS-OCT cube scans was developed. The resultant high-resolution 3D movies illustrated vitreous anatomy in a manner like triamcinolone-assisted vitrectomy or postmortem dye injection. Translational Relevance/UNASSIGNED:This machine learning model now allows for comprehensive examination of the vitreous structure beyond the vitreoretinal interface in 3D with potential applications for common disease states such as the vitreomacular traction and Macular Hole spectrum of diseases or proliferative diabetic retinopathy.

PURPOSE/OBJECTIVE:To report a case of branch retinal artery occlusion associated with paracentral acute middle maculopathy on spectral-domain optical coherence tomography presumably related to heavy cannabis consumption. METHODS:Retrospective case report. Spectral-domain optical coherence tomography, fluorescein angiography, and optical coherence tomography angiography were performed. RESULTS:A 21-year-old healthy man described the acute onset of superior visual field loss in his right eye. He admitted smoking approximately 15 g daily of cannabis for several weeks during COVID-19 confinement. Ophthalmoscopic examination of the right eye showed inferotemporal retinal whitening. Spectral-domain optical coherence tomography illustrated evidence of the ischemic cascade with diffuse hyperreflectivity of the inner and middle retinal layers within the central region of the retinal infarct and paracentral acute middle maculopathy at the border of the infarct. Optical coherence tomography angiography demonstrated predominant flow signal loss at the level of the deep retinal capillary plexus. Fluorescein angiography and complete systemic workup were unremarkable. CONCLUSION/CONCLUSIONS:Branch retinal artery occlusion and paracentral acute middle maculopathy may be related to heavy cannabis use as the result of transient arterial vasospasm.

PURPOSE/OBJECTIVE:Soft drusen and subretinal drusenoid deposits (SDDs) characterize two pathways to advanced age-related macular degeneration (AMD), with distinct genetic risks, serum risks and associated systemic diseases. METHODS:126 Subjects with AMD were classified as SDD (with or without soft drusen), or non-SDD (drusen only) by retinal imaging, with serum risks, genetic testing, and histories of cardiovascular disease (CVD) and stroke. RESULTS:There were 62 SDD subjects and 64 non-SDD subjects, 51 total had CVD or stroke.SDD correlated significantly with: lower mean serum HDL (61±18 vs. 69±22 mg/dl, p= 0.038, t test); CVD and stroke (34/51 SDD, p= 0.001, chi square); ARMS2 risk allele (p= 0.019, chi square), but not with CFH risk allele (p = 0.66). Non-SDD (drusen only) correlated/trended with: APOE2 (p= 0.032) and CETP (p= 0.072) risk alleles (chi square). Multivariate independent risks for SDD were: CVD and stroke (p= 0.008), and ARMS2 homozygous risk (p= 0.038). CONCLUSION/CONCLUSIONS:SDD and non-SDD subjects have distinct systemic associations, serum and genetic risks. SDD are associated with CVD and stroke, ARMS2 risk, and lower HDL; non-SDD with higher HDL, CFH risk and two lipid risk genes. These and other distinct associations suggest these lesions are markers for distinct diseases.

Importance/UNASSIGNED:By validating optical coherence tomography angiography (OCTA) in the analysis of type 3 macular neovascularization secondary to age-related macular degeneration, the overall value of clinical OCTA for disease observation, diagnosis, and staging is increased. Objective/UNASSIGNED:To assess the association of in vivo OCTA of type 3 macular neovascularization secondary to age-related macular degeneration with corresponding ex vivo histology. Design, Setting, and Participants/UNASSIGNED:This study included clinical imaging, laboratory microscopy, and eye-tracked clinicopathologic correlation of a single case from a community-based practice evaluated at a university-based research laboratory from 2014 to 2019. Exposures/UNASSIGNED:Infrared reflectance and eye-tracked spectral-domain OCTA clinical imaging was correlated with ex vivo high-resolution histologic images of the preserved donor eye. Eye tracking, applied to the donor eye, enabled identification of histologic features corresponding with clinical OCTA signatures. Projection artifact removal based on 2-dimensional vessel-shape estimation and a Gaussian blur filter demonstrated a robust preservation of neovascular flow signal. Main Outcomes and Measures/UNASSIGNED:Histology findings associated with clinical OCTA signatures. Three-dimensional view of neovascularization via video. Results/UNASSIGNED:A White woman in her 90s with type 3 neovascularization secondary to age-related macular degeneration was treated with 37 intravitreal injections of ranibizumab and aflibercept in the right eye. The index lesion displayed a drusenoid pigment epithelium detachment, characteristic of type 3 neovascularization. OCTA decorrelation signal in the index lesion corresponded in histology to a collagen-ensheathed vascular complex contacting basal laminar deposit that outlasted the retinal pigment epithelium. The subretinal pigment epithelium-basal laminar space contained calcified material and glial processes. No connection between the choriocapillaris and this space was observed. Video showed a columnar tangle of flow signal in the outer nuclear layer, with inflow and outflow vessels connecting to the superficial artery and vein. Conclusions and Relevance/UNASSIGNED:While this study presents only 1 case in which a vascular connection between subretinal pigment epithelium-basal laminar space and choriocapillaris was undetected, these results support the potential value of OCTA for diagnosis. OCTA decorrelation signal of type 3 neovascularization corresponded with intraretinal neovessels on histology. Projection artifact removal based on 2-dimensional vessel-shape estimation and Gaussian blur filter demonstrated their potential value for further use in OCTA decorrelation signal processing.

Purpose:To characterize macular blood flow connectivity in vivo using high-resolution optical coherence tomography (HighRes OCT). Methods:Cross-sectional, observational study. Dense (6-µm interscan distance) perifoveal HighRes OCT raster scans were performed on healthy participants. To mitigate the limitations of projection-resolved OCT-angiography, flow and structural data were used to observe the vascular structures of the superficial vascular complex (SVC) and the deep vascular complex. Vascular segmentation and rendering were performed using Imaris 9.5 software. Inflow and outflow patterns were classified according to vascular diameter and branching order from superficial arteries and veins, respectively. Results:Eight eyes from eight participants were included in this analysis, from which 422 inflow and 459 outflow connections were characterized. Arteries had direct arteriolar connections to the SVC (78%) and to the intermediate capillary plexus (ICP, 22%). Deep capillary plexus (DCP) inflow derived from small-diameter vessels succeeding ICP arterioles. The most prevalent outflow pathways coursed through superficial draining venules (74%). DCP draining venules ordinarily merged with ICP draining venules and drained independently of superficial venules in 21% of cases. The morphology of DCP draining venules in structural HighRes OCT is distinct from other vessels crossing the inner nuclear layer and can be used to identify superficial veins. Conclusions:Vascular connectivity analysis supports a hybrid circuitry of blood flow within the human parafoveal macula. Translational Relevance:Characterization of parafoveal macular blood flow connectivity in vivo using a precise segmentation of HighRes OCT is consistent with ground-truth microscopy studies and shows a hybrid circuitry.