Publications by authors named "Steven T Bailey"

50 Publications

Comparison of Central Macular Fluid Volume With Central Subfield Thickness in Patients With Diabetic Macular Edema Using Optical Coherence Tomography Angiography.

JAMA Ophthalmol 2021 May 13. Epub 2021 May 13.

Casey Eye Institute, Oregon Health & Science University, Portland.

Importance: Diabetic macular edema (DME) is the predominant cause of visual impairment in patients with type 1 or 2 diabetes. Automated fluid volume measurements using optical coherence tomography (OCT) may improve the diagnostic accuracy of DME screening.

Objective: To assess the diagnostic accuracy of an automated central macular fluid volume (CMFV) quantification using OCT for DME.

Design, Setting, And Participants: A cross-sectional observational study was conducted at a tertiary academic center among 215 patients with diabetes (1 eye each) enrolled from January 26, 2015, to December 23, 2019. All participants underwent comprehensive examinations, 6 × 6-mm macular structural OCT horizontal raster scans, and 6 × 6-mm macular OCT angiography volumetric scans. From January 1 to March 30, 2020, 2 retinal specialists reviewed the structural OCT scans independently and diagnosed DME if intraretinal or subretinal fluid was present. Diabetic macular edema was considered center involved if fluid was present within the central fovea (central 1-mm circle). A third retinal specialist arbitrated any discrepancy. The mean central subfield thickness (CST) within the central fovea was measured on structural OCT horizontal raster scans. A deep learning algorithm automatically quantified fluid volumes on 6 × 6-mm OCT angiography volumetric scans and within the central foveas (CMFV).

Main Outcomes And Measures: The area under the receiver operating characteristic curve (AUROC) and the sensitivity and specificity of CST and CMFV for DME diagnosis.

Results: We enrolled 1 eye each of 215 patients with diabetes (117 women [54.4%]; mean [SD] age, 59.6 [12.4] years). Diabetic macular edema was present in 136 eyes; 93 cases of DME were center involved. The AUROC of CMFV for diagnosis of center-involved DME (0.907 [95% CI, 0.861-0.954]) was greater than the AUROC of CST (0.832 [95% CI, 0.775-0.889]; P = .02). With the specificity set at 95%, the sensitivity of CMFV for detection of center-involved DME (78.5% [95% CI, 68.8%-86.3%]) was higher than that of CST (53.8% [95% CI, 43.1%-64.2%]; P = .002). Center-involved DME cases not detected by CST but detected by CMFV were associated with a thinner CST (290.8 μm [95% CI, 282.3-299.3 μm] vs 369.4 μm [95% CI, 347.1-391.7 μm]; P < .001), higher proportion of previous macular laser treatment (11 of 28 [39.3%; 95% CI, 21.5%-59.4%] vs 12 of 65 [18.5%; 95% CI, 9.9%-30.0%]; P = .03), and female sex (20 of 28 [71.4%; 95% CI, 51.3%-86.8%] vs 31 of 65 [47.7%; 95% CI, 35.1%-60.5%]; P = .04).

Conclusions And Relevance: These findings suggest that an automated CMFV is a more accurate diagnostic biomarker than CST for DME and may improve screening for DME.
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http://dx.doi.org/10.1001/jamaophthalmol.2021.1275DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8120439PMC
May 2021

Artificial intelligence in OCT angiography.

Prog Retin Eye Res 2021 Mar 22:100965. Epub 2021 Mar 22.

Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA; Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, 97239, USA. Electronic address:

Optical coherence tomographic angiography (OCTA) is a non-invasive imaging modality that provides three-dimensional, information-rich vascular images. With numerous studies demonstrating unique capabilities in biomarker quantification, diagnosis, and monitoring, OCTA technology has seen rapid adoption in research and clinical settings. The value of OCTA imaging is significantly enhanced by image analysis tools that provide rapid and accurate quantification of vascular features and pathology. Today, the most powerful image analysis methods are based on artificial intelligence (AI). While AI encompasses a large variety of techniques, machine-learning-based, and especially deep-learning-based, image analysis provides accurate measurements in a variety of contexts, including different diseases and regions of the eye. Here, we discuss the principles of both OCTA and AI that make their combination capable of answering new questions. We also review contemporary applications of AI in OCTA, which include accurate detection of pathologies such as choroidal neovascularization, precise quantification of retinal perfusion, and reliable disease diagnosis.
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http://dx.doi.org/10.1016/j.preteyeres.2021.100965DOI Listing
March 2021

Plexus-specific retinal capillary avascular area in exudative age-related macular degeneration with projection-resolved OCT angiography.

Br J Ophthalmol 2020 Dec 22. Epub 2020 Dec 22.

Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA

Objective: To detect the plexus-specific retinal capillary avascular area in exudative age-related macular degeneration (EAMD) with projection-resolved optical coherence tomography angiography (PR-OCTA).

Methods And Analysis: In this prospective cross-sectional single centre study, eyes with treatment-naïve EAMD underwent macular 3×3 mm OCTA with AngioVue system. OCTA scans were analysed and processed including three-dimensional projection artefact removal, retinal layer semi-automated segmentation and en face angiogram generation. Automated quantification of extrafoveal (excluding the central 1 mm circle) avascular area (EAA) were calculated on projection-resolved superficial vascular complex (SVC), intermediate capillary plexus (ICP) and deep capillary plexus (DCP), respectively.

Results: Nineteen eyes with EAMD and 19 age-matched healthy control eyes were included. There was no significant difference between the EAMD and control eyes in terms of age, sex, axial length and mean ocular perfusion pressure (all p>0.05). Compared with control eyes, EAMD eyes had significantly larger EAA in SVC (median 0.125 vs 0.059 mm, p=0.006), ICP (0.016 vs 0.000 mm, p=0.004) and DCP (0.033 vs 0.000 mm, p<0.001).

Conclusion: PR-OCTA showed that EAMD is associated with focal avascular area in all the three retinal vascular plexuses.
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http://dx.doi.org/10.1136/bjophthalmol-2020-317562DOI Listing
December 2020

Does the Cilioretinal Artery Preserve Vision in High Myopia?

Authors:
Steven T Bailey

Ophthalmol Retina 2020 10;4(10):963-964

Casey Eye Institute, Oregon Health and Science University, Portland, Oregon. Electronic address:

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http://dx.doi.org/10.1016/j.oret.2020.07.014DOI Listing
October 2020

Plexus-specific retinal vascular anatomy and pathologies as seen by projection-resolved optical coherence tomographic angiography.

Prog Retin Eye Res 2021 01 24;80:100878. Epub 2020 Jul 24.

Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA. Electronic address:

Optical coherence tomographic angiography (OCTA) is a novel technology capable of imaging retinal vasculature three-dimensionally at capillary scale without the need to inject any extrinsic dye contrast. However, projection artifacts cause superficial retinal vascular patterns to be duplicated in deeper layers, thus interfering with the clean visualization of some retinal plexuses and vascular pathologies. Projection-resolved OCTA (PR-OCTA) uses post-processing algorithms to reduce projection artifacts. With PR-OCTA, it is now possible to resolve up to 4 distinct retinal vascular plexuses in the living human eye. The technology also allows us to detect and distinguish between various retinal and optic nerve diseases. For example, optic nerve diseases such as glaucoma primarily reduces the capillary density in the superficial vascular complex, which comprises the nerve fiber layer plexus and the ganglion cell layer plexus. Outer retinal diseases such as retinitis pigmentosa primarily reduce the capillary density in the deep vascular complex, which comprises the intermediate capillary plexus and the deep capillary plexus. Retinal vascular diseases such as diabetic retinopathy and vein occlusion affect all plexuses, but with different patterns of capillary loss and vascular malformations. PR-OCTA is also useful in distinguishing various types of choroidal neovascularization and monitoring their response to anti-angiogenic medications. In retinal angiomatous proliferation and macular telangiectasia type 2, PR-OCTA can trace the pathologic vascular extension into deeper layers as the disease progress through stages. Plexus-specific visualization and measurement of retinal vascular changes are improving our ability to diagnose, stage, monitor, and assess treatment response in a wide variety of optic nerve and retinal diseases. These applications will be further enhanced with the continuing improvement of the speed and resolution of the OCT platforms, as well as the development of software algorithms to reduce artifacts, improve image quality, and make quantitative measurements.
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http://dx.doi.org/10.1016/j.preteyeres.2020.100878DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7855241PMC
January 2021

Reply.

Ophthalmology 2020 08;127(8):e60

Department of Ophthalmology, Palo Alto Medical Foundation, Palo Alto, California.

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http://dx.doi.org/10.1016/j.ophtha.2020.04.023DOI Listing
August 2020

Optical Coherence Tomography Angiography Avascular Area Association With 1-Year Treatment Requirement and Disease Progression in Diabetic Retinopathy.

Am J Ophthalmol 2020 09 29;217:268-277. Epub 2020 Apr 29.

Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, USA. Electronic address:

Purpose: To assess the association between optical coherence tomography angiography (OCTA)-quantified avascular areas (AAs) and diabetic retinopathy (DR) severity, progression, and treatment requirement in the following year.

Design: Prospective cohort study.

Methods: We recruited patients with diabetes from a tertiary academic retina practice and obtained 3-mm × 3-mm macular OCTA scans with the AngioVue system and standard 7-field color photographs at baseline and at a 1-year follow-up visit. A masked grader determined the severity of DR from the color photographs using the Early Treatment of Diabetic Retinopathy scale. A custom algorithm detected extrafoveal AA (EAA) excluding the central 1-mm circle in projection-resolved superficial vascular complex (SVC), intermediate capillary plexus (ICP), and deep capillary plexus (DCP).

Results: Of 138 patients, 92 (41 men, ranging in age from 26-84 years [mean 59.4 years]) completed 1 year of follow-up. At baseline, EAAs for SVC, ICP, and DCP were all significantly correlated with retinopathy severity (P < .0001). DCP EAA was significantly associated with worse visual acuity (r = -0.24, P = .02), but SVC and ICP EAA were not. At 1 year, 11 eyes progressed in severity by at least 1 step. Multivariate logistic regression analysis demonstrated the progression was significantly associated with baseline SVC EAA (odds ratio = 8.73, P = .04). During the follow-up period, 33 eyes underwent treatment. Multivariate analysis showed that treatment requirement was significantly associated with baseline DCP EAA (odds ratio = 3.39, P = .002). No baseline metric was associated with vision loss at 1 year.

Conclusions: EAAs detected by OCTA in diabetic eyes are significantly associated with baseline DR severity, disease progression, and treatment requirement over 1 year.
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http://dx.doi.org/10.1016/j.ajo.2020.04.024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7492451PMC
September 2020

Automated diagnosis and segmentation of choroidal neovascularization in OCT angiography using deep learning.

Biomed Opt Express 2020 Feb 14;11(2):927-944. Epub 2020 Jan 14.

Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.

Accurate identification and segmentation of choroidal neovascularization (CNV) is essential for the diagnosis and management of exudative age-related macular degeneration (AMD). Projection-resolved optical coherence tomographic angiography (PR-OCTA) enables both cross-sectional and visualization of CNV. However, CNV identification and segmentation remains difficult even with PR-OCTA due to the presence of residual artifacts. In this paper, a fully automated CNV diagnosis and segmentation algorithm using convolutional neural networks (CNNs) is described. This study used a clinical dataset, including both scans with and without CNV, and scans of eyes with different pathologies. Furthermore, no scans were excluded due to image quality. In testing, all CNV cases were diagnosed from non-CNV controls with 100% sensitivity and 95% specificity. The mean intersection over union of CNV membrane segmentation was as high as 0.88. By enabling fully automated categorization and segmentation, the proposed algorithm should offer benefits for CNV diagnosis, visualization monitoring.
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http://dx.doi.org/10.1364/BOE.379977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7041469PMC
February 2020

Retinal Vein Occlusions Preferred Practice Pattern®.

Ophthalmology 2020 Feb 25;127(2):P288-P320. Epub 2019 Sep 25.

Center for Preventative Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

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http://dx.doi.org/10.1016/j.ophtha.2019.09.029DOI Listing
February 2020

Age-Related Macular Degeneration Preferred Practice Pattern®.

Ophthalmology 2020 01 25;127(1):P1-P65. Epub 2019 Sep 25.

Center for Preventative Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

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http://dx.doi.org/10.1016/j.ophtha.2019.09.024DOI Listing
January 2020

Retinal and Ophthalmic Artery Occlusions Preferred Practice Pattern®.

Ophthalmology 2020 Feb 25;127(2):P259-P287. Epub 2019 Sep 25.

Center for Preventative Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

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http://dx.doi.org/10.1016/j.ophtha.2019.09.028DOI Listing
February 2020

Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern®.

Ophthalmology 2020 01 25;127(1):P146-P181. Epub 2019 Sep 25.

Center for Preventative Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

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http://dx.doi.org/10.1016/j.ophtha.2019.09.027DOI Listing
January 2020

Idiopathic Macular Hole Preferred Practice Pattern®.

Ophthalmology 2020 Feb 25;127(2):P184-P222. Epub 2019 Sep 25.

Center for Preventative Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

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http://dx.doi.org/10.1016/j.ophtha.2019.09.026DOI Listing
February 2020

Diabetic Retinopathy Preferred Practice Pattern®.

Ophthalmology 2020 01 25;127(1):P66-P145. Epub 2019 Sep 25.

Center for Preventative Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

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http://dx.doi.org/10.1016/j.ophtha.2019.09.025DOI Listing
January 2020

Idiopathic Epiretinal Membrane and Vitreomacular Traction Preferred Practice Pattern®.

Ophthalmology 2020 Feb 25;127(2):P145-P183. Epub 2019 Sep 25.

Center for Preventative Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

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http://dx.doi.org/10.1016/j.ophtha.2019.09.022DOI Listing
February 2020

Detecting and measuring areas of choriocapillaris low perfusion in intermediate, non-neovascular age-related macular degeneration.

Neurophotonics 2019 Oct 12;6(4):041108. Epub 2019 Sep 12.

Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States.

Age-related macular degeneration (AMD) is a vision-threatening disease that affects the outer retina and choroid of elderly adults. Because photoreceptors are found in the outer retina and rely primarily on the trophic support of the underlying choriocapillaris, imaging of flow or lack thereof in choriocapillaris by optical coherence tomography angiography (OCTA) has great clinical potential in AMD assessment. We introduce a metric using OCTA, named "focal perfusion loss" (FPL) to describe the effects of age and non-neovascular AMD on choriocapillaris flow. Because OCTA imaging of choriocapillaris is vulnerable to artifacts-namely motion, projections, segmentation errors, and shadows-they are removed by postprocessing software. The shadow detection software is a machine learning algorithm recently developed for the evaluation of the retinal circulation and here adapted for choriocapillaris analysis. It aims to exclude areas with unreliable flow signal due to blocking of the OCT beam by objects anterior to the choriocapillaris (e.g., drusen, retinal vessels, vitreous floaters, and iris). We found that both the FPL and the capillary density were able to detect changes in the choriocapillaris of AMD and healthy age-matched subjects with respect to young controls. The dominant cause of shadowing in AMD is drusen, and the shadow exclusion algorithm helps determine which areas under drusen retain sufficient signal for perfusion evaluation and which areas must be excluded. Such analysis allowed us to determine unambiguously that choriocapillaris density under drusen is indeed reduced.
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http://dx.doi.org/10.1117/1.NPh.6.4.041108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6739623PMC
October 2019

Detection of Reduced Retinal Vessel Density in Eyes with Geographic Atrophy Secondary to Age-Related Macular Degeneration Using Projection-Resolved Optical Coherence Tomography Angiography.

Am J Ophthalmol 2020 01 14;209:206-212. Epub 2019 Sep 14.

Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, USA. Electronic address:

Purpose: To compare retinal vessel density in eyes with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) to age-matched healthy eyes by using projection-resolved optical coherence tomography angiography (PR-OCTA).

Design: Prospective cross-sectional study.

Methods: Study participants underwent macular 3- × 3-mm OCTA scans with spectral domain OCTA. Reflectance-compensated retinal vessel densities were calculated on projection-resolved superficial vascular complex (SVC), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). Quantitative analysis using normalized deviation compared the retinal vessel density in GA regions, 500-μm GA rim regions, and non-GA regions to similar macular locations in control eyes.

Results: Ten eyes with GA and 10 control eyes were studied. Eyes with GA had significantly lower vessel density in the SVC (54.8 ± 2.4% vs. 60.8 ± 3.1%; P < 0.001), ICP (34.0 ± 1.5% vs. 37.3 ± 1.7%; P = 0.003) and DCP (24.4 ± 2.3% vs. 28.0 ± 2.3%; P < 0.001) than control eyes. Retinal vessel density within the GA region decreased significantly in SVC, ICP, and DCP. Retinal vessel density in the GA rim region decreased in SVC and ICP but not in DCP. The non-GA region did not significantly deviate from normal controls. Eyes with GA had significantly reduced photoreceptor layer thickness; but similar nerve fiber layer, ganglion cell complex, inner nuclear layer, and outer plexiform layer thickness.

Conclusions: Eyes with GA have reduced retinal vessel density in SVC, ICP, and DCP compared to those in controls. Loss is greatest within regions of GA. Vessel density may be more sensitive than retinal layer thickness measurement in the detection of inner retinal change in eyes with GA.
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http://dx.doi.org/10.1016/j.ajo.2019.09.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6911625PMC
January 2020

Detection of Nonexudative Choroidal Neovascularization and Progression to Exudative Choroidal Neovascularization Using OCT Angiography.

Ophthalmol Retina 2019 08 21;3(8):629-636. Epub 2019 Mar 21.

Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.

Purpose: To detect nonexudative choroidal neovascularization (CNV) in age-related macular degeneration (AMD) with OCT angiography (OCTA) and determine the risk of exudative CNV developing compared with eyes without nonexudative CNV.

Design: Prospective, longitudinal, observational study.

Participants: Consecutive patients with drusen and pigmentary changes in the study eye and exudative neovascular AMD in the fellow eye.

Methods: In this prospective observational study, participants underwent spectral-domain OCTA (AngioVue; Optovue, Inc, Fremont, CA), clinical examination, and structural OCT at baseline and 6-month intervals for 2 years. OCT angiography images were exported for custom processing to remove projection artifact and calculate CNV vessel area.

Main Outcome Measures: Rate of developing exudation in eyes with and without nonexudative CNV as detected by OCTA on regular follow-up.

Results: Sixty-three study participants were followed up every 6 months and 48 completed the 2-year study. Mean age was 78 years and 60.3% were female. On the baseline visit, 5 eyes (7.9%) were found to have nonexudative CNV by OCTA, and 3 of them demonstrated exudation. Of 58 eyes with a normal OCTA on baseline visit, 5 eyes developed nonexudative CNV during a follow-up visit. All 5 of these nonexudative CNV went on to develop exudation in subsequent visits. Overall, 8 of the 10 eyes with nonexudative CNV developed exudation with a mean time of 8 months and mean CNV area growth rate of 20% per month (P = 0.014, exponential model). Initiation of antiangiogenic treatment halted their growth. In comparison, exudation occurred in only 6 of the 53 eyes (11%) that lacked a precursor nonexudative CNV. Cox proportional hazard analysis showed that having nonexudative CNV detected was associated with an 18.1-fold increase in the rate of exudation subsequently developing (P < 0.0001).

Conclusions: Nonexudative CNV frequently is detected by OCTA in the fellow eyes of those with exudative CNV. These lesions carry a high risk of exudation developing within the first year after detection and could benefit from close monitoring. The high risk of progression may justify prophylactic treatment; further studies are needed.
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http://dx.doi.org/10.1016/j.oret.2019.03.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684834PMC
August 2019

Maximum value projection produces better OCT angiograms than mean value projection.

Biomed Opt Express 2018 Dec 26;9(12):6412-6424. Epub 2018 Nov 26.

Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA.

Optical coherence tomography angiography (OCTA) images rely on data projections for both qualitative and quantitative interpretation. Both maximum value and mean value projections are commonly used, and many researchers consider them essentially interchangeable approaches. On the contrary, we find that maximum value projection achieves a consistently higher signal-to-noise ratio and higher image contrast across multiple vascular layers, in both healthy eyes and for each disease examined.
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http://dx.doi.org/10.1364/BOE.9.006412DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6491019PMC
December 2018

DETECTION OF CLINICALLY UNSUSPECTED RETINAL NEOVASCULARIZATION WITH WIDE-FIELD OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

Retina 2020 May;40(5):891-897

Department of Ophthalmology, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon; and.

Purpose: To evaluate wide-field optical coherence tomography angiography (OCTA) for detection of clinically unsuspected neovascularization (NV) in diabetic retinopathy (DR).

Methods: This prospective observational single-center study included adult patients with a clinical diagnosis of nonproliferative DR. Participants underwent a clinical examination, standard 7-field color photography, and OCTA with commercial and prototype swept-source devices. The wide-field OCTA was achieved by montaging five 6 × 10-mm scans from a prototype device into a 25 × 10-mm image and three 6 × 6-mm scans from a commercial device into a 15 × 6-mm image. A masked grader determined the retinopathy severity from color photographs. Two trained readers examined conventional and wide-field OCTA images for the presence of NV.

Results: Of 27 participants, photographic grading found 13 mild, 7 moderate, and 7 severe nonproliferative DR. Conventional 6 × 6-mm OCTA detected NV in 2 eyes (7%) and none with 3 × 3-mm scans. Both prototype and commercial wide-field OCTA detected NV in two additional eyes. The mean area of NV was 0.38 mm (range 0.17-0.54 mm). All eyes with OCTA-detected NV were photographically graded as severe nonproliferative DR.

Conclusion: Wide-field OCTA can detect small NV not seen on clinical examination or color photographs and may improve the clinical evaluation of DR.
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http://dx.doi.org/10.1097/IAE.0000000000002487DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6722037PMC
May 2020

Classification of Choroidal Neovascularization Using Projection-Resolved Optical Coherence Tomographic Angiography.

Invest Ophthalmol Vis Sci 2018 08;59(10):4285-4291

Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States.

Purpose: To evaluate if projection-resolved optical coherence tomographic angiography (PR-OCTA) reduces projection artifact with less attenuation of choroidal neovascularization (CNV) flow signal compared to conventional OCTA with slab subtraction.

Methods: In this retrospective cross-sectional study, participants with subfoveal treatment-naïve CNV secondary to age-related macular degeneration underwent OCTA. Scans were exported for custom processing including manual segmentation as necessary, application of slab subtraction and PR-OCTA algorithm, and calculation of CNV vascular area and connectivity. CNV was classified as type 1, minimally type 2, or predominantly type 2 based on fluorescein angiography (FA) and OCT. Two masked retina specialists independently classified CNV using cross-sectional conventional OCTA and PR-OCTA.

Results: A total of 17 eyes were enrolled in this study. Mean CNV vessel area (mm2) was 0.67 ± 0.51 for PR-OCTA and 0.53 ± 0.41 for slab subtraction (P = 0.018). Mean vascular connectivity was 96.80 ± 1.28 for PR-OCTA and 90.90 ± 4.42 (P = 0.018) for slab subtraction. Within-visit repeatability (coefficient of variation) of PR-OCTA was 0.044 for CNV vessel area and 0.012 for vascular connectivity, compared to 0.093 and 0.028 by slab subtraction. PR-OCTA classification agreement with FA/OCT was 88.2% and 76.5% for the two graders, while conventional OCTA agreement was 58.8% and 70.6% (grader 1, P = 0.025; grader 2, P = 0.56). Moreover, PR-OCTA enabled the individual quantification of type 1 and type 2 components of a CNV.

Conclusions: PR-OCTA had greater CNV vessel area and vascular connectivity, as well as better repeatability, compared to slab subtraction, suggesting PR-OCTA is a superior technique for imaging CNV. Furthermore, PR-OCTA removes projection artifact on cross-sectional OCTA, improving the ability to classify and quantify CNV components.
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http://dx.doi.org/10.1167/iovs.18-24624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6108780PMC
August 2018

Quantitative Evaluation of Choroidal Neovascularization under Pro Re Nata Anti-Vascular Endothelial Growth Factor Therapy with OCT Angiography.

Ophthalmol Retina 2018 Sep 2;2(9):931-941. Epub 2018 Mar 2.

Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.

Purpose: To use optical coherence tomography angiography (OCTA) derived quantitative metrics to assess the response of choroidal neovascularization to pro-re-nata (PRN) anti-endothelial growth factor (anti-VEGF) treatment in neovascular age-related macular degeneration (AMD).

Design: Prospective longitudinal cohort study.

Participants: Fourteen eyes from 14 study participants with treatment-naïve neovascular AMD were enrolled.

Methods: Subjects were evaluated monthly and treated with intravitreal anti-VEGF agents under a PRN protocol for one year. At each visit, two 3×3 mm OCTA scans were obtained. Custom image processing was applied to segment the outer retinal slab, suppress projection artifact, and automatically detect CNV. CNV membrane area (mm) and CNV vessel area (mm) was calculated.

Main Outcomes: Individual and mean CNV membrane area and CNV vessel area at each visit; within-visit repeatability determined by coefficient of variation.

Results: Eight eyes had entire CNV within 3×3 mm scanning area and had adequate image quality for CNV quantification. One case (case #2) was excluded from analysis due to the presence of a large subretinal hemorrhage overlying the CNV membrane. In the remaining cases, CNV vessel area was reduced by 39%, 50%, 43%, and 41% at months 1, 3, 6, and 12 respectively. CNV membrane area was reduced by 39%, 51%, 54%, and 45% at months 1, 3, 6, and 12. At month 6, mean change from baseline was not statistically significant for CNV vessel area, while it was statistically significant for CNV membrane area. Neither metric was significantly different compared to baseline at month 12. Individual analyses revealed each CNV had a unique response under PRN treatment. Within-visit repeatability was was 7.96% (coefficient of variation) for CNV vessel area and 7.37% for CNV membrane area.

Conclusions: In this small exploratory study of CNV response to PRN anti-VEGF treatment, both CNV vessel area and membrane area were reduced compared to baseline after three months. After one year of follow-up, these reductions were no longer statistically significant. When anti-VEGF treatment was held, increasing CNV vessel area over time often resulted in exudation, but it was not possible to exactly when exudation occurs.
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http://dx.doi.org/10.1016/j.oret.2018.01.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6139650PMC
September 2018

Plexus-Specific Detection of Retinal Vascular Pathologic Conditions with Projection-Resolved OCT Angiography.

Ophthalmol Retina 2018 Aug 10;2(8):816-826. Epub 2018 Jan 10.

Casey Eye Institute, Oregon Health & Science University, 3375 SW Terwilliger Blvd, Portland, OR 97239.

Objective: To evaluate the projection-resolved (PR) optical coherence tomography angiography (OCTA) algorithm in detecting plexus-specific vascular abnormalities in retinal pathologies.

Design: Cross-sectional observational clinical study.

Participants: Patients diagnosed with retinal vascular diseases and healthy volunteers.

Methods: Eyes were imaged using an OCT system operating at 840 nm and employing the split-spectrum amplitude decorrelation algorithm. A novel algorithm suppressed projection artifacts inherent to OCTA. The volumetric scans were segmented and visualized on different plexuses.

Main Outcome Measures: Qualitative observation of vascular abnormalities on both cross-sectional and PR-OCTA images.

Results: Eight illustrative cases are reported. In cases of diabetic retinopathy, retinal vessel occlusion, and retinitis pigmentosa, PR-OCTA detected retinal nonperfusion regions within deeper retinal plexuses not visualized by conventional OCTA. In age-related macular degeneration, cross-sectional PR-OCTA permitted the classification of choroidal neovascularization, and, in a case of retinal angiomatous proliferation, identified a vertical vessel contiguous with the deep capillary plexus. In macular telangiectasia, PR-OCTA detected a diving perifoveal vein and delineated subretinal neovascularization.

Conclusions: Application of PR-OCTA promises to improve sensitive, accurate evaluation of individual vascular plexuses in multiple retinal diseases.
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http://dx.doi.org/10.1016/j.oret.2017.11.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6106769PMC
August 2018

Automatic quantification of choroidal neovascularization lesion area on OCT angiography based on density cell-like P systems with active membranes.

Biomed Opt Express 2018 Jul 20;9(7):3208-3219. Epub 2018 Jun 20.

Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA.

Detecting and quantifying the size of choroidal neovascularization (CNV) is important for the diagnosis and assessment of neovascular age-related macular degeneration. Depth-resolved imaging of the retinal and choroidal vasculature by optical coherence tomography angiography (OCTA) has enabled the visualization of CNV. However, due to the prevalence of artifacts, it is difficult to segment and quantify the CNV lesion area automatically. We have previously described a saliency algorithm for CNV detection that could identify a CNV lesion area with 83% accuracy. However, this method works under the assumption that the CNV region is the most salient area for visual attention in the whole image and consequently, errors occur when this requirement is not met (e.g. when the lesion occupies a large portion of the image). Moreover, saliency image processing methods cannot extract the edges of the salient object very accurately. In this paper, we propose a novel and automatic CNV segmentation method based on an unsupervised and parallel machine learning technique named density cell-like P systems (DEC P systems). DEC P systems integrate the idea of a modified clustering algorithm into cell-like P systems. This method improved the accuracy of detection to 87.2% on 22 subjects and obtained clear boundaries of the CNV lesions.
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http://dx.doi.org/10.1364/BOE.9.003208DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033576PMC
July 2018

Projection-resolved optical coherence tomography angiography exhibiting early flow prior to clinically observed retinal angiomatous proliferation.

Am J Ophthalmol Case Rep 2017 Dec 6;8:53-57. Epub 2017 Oct 6.

Casey Eye Institute, Oregon Health and Science University, Portland, OR, United States.

Purpose: The purpose of this study is to analyze early retinal angiomatous proliferation (RAP) utilizing a novel imaging modality, Projection-Resolved Optical Coherence Tomography Angiography (PR-OCTA).

Observations: Five months prior to the diagnosis of a RAP lesion, cross-sectional PR-OCTA demonstrated flow in the outer retina contiguous with the deep retinal capillary plexus (DCP) and adjacent to a small pigment epithelial detachment. After development of a clinically visible RAP lesion, cross-sectional PR-OCTA demonstrated the RAP lesion connecting DCP and sub-retinal pigment epithelial neovascularization.

Conclusions & Importance: This is the first report of PR-OCTA demonstrating abnormal flow in the outer retina prior to the development of a clinically detectable RAP lesion. PR-OCTA may be useful for surveillance and to help further characterize and stage RAP lesions.
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http://dx.doi.org/10.1016/j.ajoc.2017.10.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5731673PMC
December 2017

Automated drusen detection in dry age-related macular degeneration by multiple-depth, optical coherence tomography.

Biomed Opt Express 2017 Nov 17;8(11):5049-5064. Epub 2017 Oct 17.

Casey Eye Institute, Oregon Health & Science University, Portland, OR, 27239, USA.

We introduce a method to automatically detect drusen in dry age-related macular degeneration (AMD) from optical coherence tomography with minimum need for layer segmentation. The method is based on the detection of drusen areas in C-scans at certain distances above the Bruch's membrane, circumventing the difficult task of pathologic retinal pigment epithelium segmentation. All types of drusen can be detected, including the challenging subretinal drusenoid deposits (pseudodrusen). The high sensitivity and accuracy demonstrated here shows its potential for detection of drusen onset in early AMD.
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http://dx.doi.org/10.1364/BOE.8.005049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695952PMC
November 2017

Sensitivity and Specificity of OCT Angiography to Detect Choroidal Neovascularization.

Ophthalmol Retina 2017 Jul-Aug;1(4):294-303

Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.

Purpose: To determine the sensitivity and specificity of optical coherence tomography angiography (OCTA) in the detection of choroidal neovascularization (CNV) in age-related macular degeneration (AMD).

Design: Prospective case series.

Subjects: Prospective series of seventy-two eyes were studied, which included eyes with treatment-naive CNV due to AMD, non-neovascular AMD, and normal controls.

Methods: All eyes underwent OCTA with a spectral domain (SD) OCT (Optovue, Inc.). The 3D angiogram was segmented into separate views including the inner retinal angiogram, outer retinal angiogram, and choriocapillaris angiogram. Detection of abnormal flow in the outer retina served as candidate CNV with OCTA. Masked graders reviewed structural OCT alone, OCTA alone, and OCTA combined with cross-sectional OCTA for the presence of CNV.

Main Outcome Measure: The sensitivity and specificity of CNV detection compared to the gold standard of fluorescein angiography (FA) and OCT was determined for structural SD-OCT alone, OCTA alone, and with OCTA combined with cross-sectional OCTA.

Results: Of 32 eyes with CNV, both graders identified 26 true positives with OCTA alone, resulting in a sensitivity of 81.3%. Four of the 6 false negatives had large subretinal hemorrhage (SRH) and sensitivity improved to 94% for both graders if eyes with SRH were excluded. The addition of cross-sectional OCTA along with OCTA improved the sensitivity to 100% for both graders. Structural OCT alone also had a sensitivity of 100%. The specificity of OCTA alone was 92.5% for grader A and 97.5% for grader B. The specificity of structural OCT alone was 97.5% for grader A and 85% for grader B. Cross-sectional OCTA combined with OCTA had a specificity of 97.5% for grader A and 100% for grader B.

Conclusions: Sensitivity and specificity for CNV detection with OCTA combined with cross-sectional OCTA approaches that of the gold standard of FA with OCT, and it is better than OCTA alone. Structural OCT alone has excellent sensitivity for CNV detection. False positives from structural OCT can be mitigated with the addition of flow information with OCTA.
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http://dx.doi.org/10.1016/j.oret.2017.02.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5648075PMC
October 2017

Time Requirements for Electronic Health Record Use in an Academic Ophthalmology Center.

JAMA Ophthalmol 2017 11;135(11):1250-1257

Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland.

Importance: Electronic health record (EHR) systems have transformed the practice of medicine. However, physicians have raised concerns that EHR time requirements have negatively affected their productivity. Meanwhile, evolving approaches toward physician reimbursement will require additional documentation to measure quality and cost of care. To date, little quantitative analysis has rigorously studied these topics.

Objective: To examine ophthalmologist time requirements for EHR use.

Design, Setting, And Participants: A single-center cohort study was conducted between September 1, 2013, and December 31, 2016, among 27 stable departmental ophthalmologists (defined as attending ophthalmologists who worked at the study institution for ≥6 months before and after the study period). Ophthalmologists who did not have a standard clinical practice or who did not use the EHR were excluded.

Exposures: Time stamps from the medical record and EHR audit log were analyzed to measure the length of time required by ophthalmologists for EHR use. Ophthalmologists underwent manual time-motion observation to measure the length of time spent directly with patients on the following 3 activities: EHR use, conversation, and examination.

Main Outcomes And Measures: The study outcomes were time spent by ophthalmologists directly with patients on EHR use, conversation, and examination as well as total time required by ophthalmologists for EHR use.

Results: Among the 27 ophthalmologists in this study (10 women and 17 men; mean [SD] age, 47.3 [10.7] years [median, 44; range, 34-73 years]) the mean (SD) total ophthalmologist examination time was 11.2 (6.3) minutes per patient, of which 3.0 (1.8) minutes (27% of the examination time) were spent on EHR use, 4.7 (4.2) minutes (42%) on conversation, and 3.5 (2.3) minutes (31%) on examination. Mean (SD) total ophthalmologist time spent using the EHR was 10.8 (5.0) minutes per encounter (range, 5.8-28.6 minutes). The typical ophthalmologist spent 3.7 hours using the EHR for a full day of clinic: 2.1 hours during examinations and 1.6 hours outside the clinic session. Linear mixed effects models showed a positive association between EHR use and billing level and a negative association between EHR use per encounter and clinic volume. Each additional encounter per clinic was associated with a decrease of 1.7 minutes (95% CI, -4.3 to 1.0) of EHR use time per encounter for ophthalmologists with high mean billing levels (adjusted R2 = 0.42; P = .01).

Conclusions And Relevance: Ophthalmologists have limited time with patients during office visits, and EHR use requires a substantial portion of that time. There is variability in EHR use patterns among ophthalmologists.
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http://dx.doi.org/10.1001/jamaophthalmol.2017.4187DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5710390PMC
November 2017

Reflectance-based projection-resolved optical coherence tomography angiography [Invited].

Biomed Opt Express 2017 Mar 15;8(3):1536-1548. Epub 2017 Feb 15.

Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.

Optical coherence tomography angiography (OCTA) is limited by projection artifacts from the superficial blood vessels onto deeper layers. We have recently described projection-resolved (PR) OCTA that solves the ambiguity between flow and flow projection along each axial scan and suppresses the artifact on both and cross-sectional angiograms. While this method significantly improved the depth resolution of OCTA, the vascular integrity of the deeper layers was not fully preserved. In this study, we propose a novel reflectance-based projection-resolved (rbPR) OCTA algorithm which uses OCT reflectance to enhance the flow signal and suppress the projection artifacts in 3-dimensional OCTA. We demonstrated quantitatively that rbPR improved the vascular connectivity and improved the discrimination of the deeper plexus angiograms in healthy eyes, compared to prior PR-OCTA method. We also demonstrated qualitatively that rbPR removes flow projection artifacts more completely from the outer retinal slab in the eyes with age-related macular degeneration, and preserves vascular integrity of the intermediate and deep capillary plexuses in the eyes with diabetic retinopathy. Additionally, this method improves the resolution of the choriocapillaris and demonstrates details comparable to scanning electron microscopy.
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http://dx.doi.org/10.1364/BOE.8.001536DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5480563PMC
March 2017

Optical coherence tomographic angiography of choroidal neovascularization ill-defined with fluorescein angiography.

Br J Ophthalmol 2017 Jan 2;101(1):45-50. Epub 2016 Dec 2.

Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA.

Purpose: To evaluate the morphological structure of ill-defined choroidal neovascularisation (CNV) with traditional fluorescein angiography (FA) compared with optical coherence tomographic angiography (OCTA).

Methods: A retrospective case series study of 11 eyes with ill-defined CNV on FA was performed. Eyes were scanned with commercially available spectral-domain optical coherence tomography (OCT) (70 000 A-scans/s). The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to distinguish blood flow from static tissue. En face OCT angiograms were compared with FA.

Results: Eleven cases of ill-defined CNV on FA were identified from 10 study participants. Mean age of the participants was 74.5±6.8 years. Six cases had late leakage from undetermined source (LLUS) and five had fibrovascular pigment epithelial detachment (FVPED). Combining cross-sectional structural OCT with OCT angiograms, all cases were found to have type 1 CNV that corresponded to occult CNV with FA. In all cases of occult CNV on FA, distinct vascular structures were visible with OCTA in the outer retinal/retinal pigment epithelium slab. The mean CNV vessel area was 2.61±3.65 mm. The mean CNV vessel area in cases with FVPED was larger than that in cases with LLUS (4.69±4.72 mm compared with 0.85±0.90 mm, Mann-Whitney p value=0.04).

Conclusions: Although the sample size is small to draw conclusions and the nature of work is retrospective and descriptive, OCTA has the potential to improve visualisation of ill-defined CNV with dye-based angiography, including occult CNV.
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http://dx.doi.org/10.1136/bjophthalmol-2016-309094DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5805390PMC
January 2017