Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-Related Macular Degeneration

Purpose To detect and quantify choroidal neovascularization (CNV) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT) angiography. Design Observational, cross-sectional study. Participants A total of 5 normal subjects and 5 subjects with neovascular AMD were included. Methods A total of 5 eyes with neovascular AMD and 5 normal age-matched controls were scanned by a high-speed (100 000 A-scans/seconds) 1050-nm wavelength swept-source OCT. The macular angiography scan covered a 3×3-mm area and comprised 200×200×8 A-scans acquired in 3.5 seconds. Flow was detected using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Motion artifacts were removed by 3-dimensional (3D) orthogonal registration and merging of 4 scans. The 3D angiography was segmented into 3 layers: inner retina (to show retinal vasculature), outer retina (to identify CNV), and choroid. En face maximum projection was used to obtain 2-dimensional angiograms from the 3 layers. The CNV area and flow index were computed from the en face OCT angiogram of the outer retinal layer. Flow (decorrelation) and structural data were combined in composite color angiograms for both en face and cross-sectional views. Main Outcome Measures The CNV angiogram, CNV area, and CNV flow index. Results En face OCT angiograms of CNV showed sizes and locations that were confirmed by fluorescein angiography (FA). Optical coherence tomography angiography provided more distinct vascular network patterns that were less obscured by subretinal hemorrhage. The en face angiograms also showed areas of reduced choroidal flow adjacent to the CNV in all cases and significantly reduced retinal flow in 1 case. Cross-sectional angiograms were used to visualize CNV location relative to the retinal pigment epithelium and Bruch's layer and classify type I and type II CNV. A feeder vessel could be identified in 1 case. Higher flow indexes were associated with larger CNV and type II CNV. Conclusions Optical coherence tomography angiography provides depth-resolved information and detailed images of CNV in neovascular AMD. Quantitative information regarding CNV flow and area can be obtained. Further studies are needed to assess the role of quantitative OCT angiography in the evaluation and treatment of neovascular AMD.National Institutes of Health (U.S.) (Grant 1R01 EY023285-01)National Institutes of Health (U.S.) (Grant R01 EY013516)Rosenbaum's P30EY010572National Institutes of Health (U.S.) (Clinical and Translational Science Award Grant UL1TR000128)Research to Prevent Blindness, Inc. (United States) (Grant R01-EY11289-26)United States. Air Force Office of Scientific Research (FA9550-10-1-0551)German Research Foundation (DFG-HO-1791/11-1)German Research Foundation (DFG-GSC80-SAOT

Quantitative optical coherence tomography angiography of vascular abnormalities in the living human eye

Retinal vascular diseases are important causes of vision loss. A detailed evaluation of the vascular abnormalities facilitates diagnosis and treatment in these diseases. Optical coherence tomography (OCT) angiography using the highly efficient split-spectrum amplitude decorrelation angiography algorithm offers an alternative to conventional dye-based retinal angiography. OCT angiography has several advantages, including 3D visualization of retinal and choroidal circulations (including the choriocapillaris) and avoidance of dye injection-related complications. Results from six illustrative cases are reported. In diabetic retinopathy, OCT angiography can detect neovascularization and quantify ischemia. In age-related macular degeneration, choroidal neovascularization can be observed without the obscuration of details caused by dye leakage in conventional angiography. Choriocapillaris dysfunction can be detected in the nonneovascular form of the disease, furthering our understanding of pathogenesis. In choroideremia, OCT's ability to show choroidal and retinal vascular dysfunction separately may be valuable in predicting progression and assessing treatment response. OCT angiography shows promise as a noninvasive alternative to dye-based angiography for highly detailed, in vivo, 3D, quantitative evaluation of retinal vascular abnormalities.National Institutes of Health (U.S.) (Grant R01-EY023285)National Institutes of Health (U.S.) (Grant R01-EY024544)National Institutes of Health (U.S.) (Grant DP3 DK104397)National Institutes of Health (U.S.) (Grant R01-EY11289)National Institutes of Health (U.S.) (Grant K08-EY021186)National Institutes of Health (U.S.) (Grant T32-EY23211)National Institutes of Health (U.S.) (Grant P30-EY010572)Clinical and Translational Science Award Grant UL1TR000128Research to Prevent Blindness, Inc. (United States) (Grant and Career Development Award CD-NMT-0914-0659-OHSU)United States. Air Force Office of Scientific Research (Foundation Fighting Blindness Career Development Award FA9550-10-1-0551)German Research Foundation (Grant DFG-HO-1791/11-1)German Research Foundation (Grant DFG-GSC80-SAOT

The use of optical coherence tomography in the assessment of diabetic retinopathy and maculopathy

This review was performed to assess the use of optical coherence tomography in diabetic retinopathy and maculopathy and its application in the diagnosis and management of these conditions. A comprehensive literature search on MEDLINE was performed for studies published until 2013 with key words 'diabetes mellitus', 'optical coherence tomography', 'diabetic retinopathy', 'diabetic maculopathy', 'intersessional repeatability', 'diurnal variation' , 'fundus autofluorescence' and 'treatment'. Search results were limited to studies published in English and in human subjects only. The Early Treatment Diabetic Retinopathy Study established the current standard of care for diabetic retinopathy and maculopathy with the diagnosis based on slit-lamp biomicroscopy, indirect ophthalmoscopy, and fluorescein angiography. There has been a recent shift to the use of optical coherence tomography in the qualitative and quantitative assessment of such diseases. Furthermore, the advancement of optical coherence tomography from time-domain to spectraldomain technology allows us to visualize pathological changes of diabetic maculopathy in details in different retinal layers. Such observed changes have been used to establish new classifications of diabetic maculopathy. The high sensitivity and quantitative nature of optical coherence tomography make it a highly popular modality used extensively to monitor disease progression and efficacy of new treatment modalities. Optical coherence tomography plays a crucial role in the modern clinical management of diabetic retinopathy and maculopathy. Its use has revolutionized the understanding and management of these eye diseases.published_or_final_versio

Optical Coherence Tomography Angiography – A New Insight Into Macular Vasculature

Optical coherence tomography angiography (OCT-A) is a new non-invasive technology for imaging of retinal and choroidal vasculature of the macular area with resolution comparable to histological sections. OCT-A does not require usage of intravenous dye, contrary to fluorescein angiography, the current gold standard for imaging of retinal vessels, and indocyanine-green angiography, which is important for imaging of choroidal vessels. With the advancements in optical coherence tomography (OCT) scanning speeds and creation of powerful algorithms for improvement of image quality in recent years, OCT-A imaging of macular vasculature, superficial, deep and avascular retinal complex, as well as choriocapillaris and deep choroid has become available in everyday clinical practice. This review covers aspects important for understanding choroidal and retinal blood supply, as well as the development, mechanisms and clinical application of OCT and OCT-A technology. (Bajtl D, Bjeloš M, Bušić M, Rak B, Križanović A, Kuzmanović Elabjer B. Optical Coherence Tomography Angiography – A New Insight Into Macular Vasculature. SEEMEDJ 2019; 3(2); 63-75

Graefes Arch Clin Exp Ophthalmol

Purpose:Automated segmentation of retinal layers by spectral-domain optical coherence tomography (SD-OCT) is usually erroneous in the presence of retinal diseases. The purpose of this study is to report the changes in ganglion cell complex (GCC) comprising retina nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) in neovascular age-related macular degeneration (AMD) patients by manually correcting the automated segmentation errors.Methods:Thirty-eyes of 30 patients with new-onset choroidal neovascularization secondary to neovascular AMD and 30 eyes of 30 healthy subjects were included. The inner retinal thicknesses were measured using early treatment diabetic retinopathy circle in the central 1 milimeter (mm) (fovea) and surrounding 3 mm diameter (parafovea) after checking the accuracy of automated segmentation lines. Manual segmentation was done to ensure the accurate segmentation, when needed.Results:Neovascular AMD patients had thicker mean RNFL, GCL, IPL and GCC thicknesses within the fovea compared to healthy eyes (p=0.04, p=0.001, p=0.032 and p=0.005, respectively). In the parafoveal area, among the thickness related measurements, the only significant difference was a thicker mean RNFL (p=0.002).Conclusion:Diffuse thickening of inner retinal layers in neovascular AMD may overestimate actual GCC thickness within fovea. This pseudo-increase in GCC thickness and inner retinal layers in general likely does not reflect more cells or tissue, but rather diffuse edema which leads to a falsely increased reading of layer thickness. Such false readings may also make the assessment of other conditions that lead to reduced inner retinal layer thickness such as glaucoma, optic nerve disease or retinovascular occlusions more difficult.P30 EY022589/EY/NEI NIH HHS/United StatesU50 DP523414/DP/NCCDPHP CDC HHS/United StatesP30 EY022589/EY/NEI NIH HHS/United States2020-05-05T00:00:00Z30094716PMC7199443763

The Role of Optical Coherence Tomography Angiography in Glaucoma

Glaucoma is the second leading cause of blindness worldwide, affecting eighty million people globally and three million patients in the USA. Primary open-angle glaucoma, the most common type, is a multifactorial progressive optic nerve neurodegenerative disorder that leads to loss of optic nerve head (ONH) tissue, thinning of the retinal nerve fiber layer, and corresponding visual field (VF) defects with or without elevated intraocular pressure (IOP). Risk factors include older age, black or Hispanic race, elevated IOP, thin central corneal thickness, disk hemorrhage, and low ocular perfusion pressure. The two prevalent theories explaining glaucomatous damage are mechanical (elevated IOP) and vascular (compromised optic nerve perfusion). Current diagnostic methods, such as measuring IOP, VF testing, and ONH evaluation, are subjective and often unreliable. Optical coherence tomography angiography (OCTA) is a rapid, non-invasive imaging modality that provides 3-D, volumetric details of both the structure and vascular networks of the retina and optic nerve. Various researchers have shown that OCTA provides an accurate and objective evaluation of the retina and the optic nerve in glaucoma. This chapter describes the role of OCTA in managing patients with glaucoma