Optical Coherence Tomography Angiography In Glaucoma Research Articles

Applications of optical coherence tomography angiography in glaucoma: current status and future directions.

Glaucoma is a leading cause of irreversible blindness worldwide, with its pathophysiology remaining inadequately understood. Among the various proposed theories, the vascular theory, suggesting a crucial role of retinal vasculature deterioration in glaucoma onset and progression, has gained significant attention. Traditional imaging techniques, such as fundus fluorescein angiography, are limited by their invasive nature, time consumption, and qualitative output, which restrict their efficacy in detailed retinal vessel examination. Optical coherence tomography angiography (OCTA) emerges as a revolutionary imaging modality, offering non-invasive, detailed visualization of the retinal and optic nerve head microvasculature, thereby marking a significant advancement in glaucoma diagnostics and management. Since its introduction, OCTA has been extensively utilized for retinal vasculature imaging, underscoring its potential to enhance our understanding of glaucoma's pathophysiology, improving diagnosis, and monitoring disease progression. This review aims to summarize the current knowledge regarding the role of OCTA in glaucoma, particularly its potential applications in diagnosing, monitoring, and understanding the pathophysiology of the disease. Parameters pertinent to glaucoma will be elucidated to illustrate the utility of OCTA as a tool to guide glaucoma management.

A Deep Learning System Using Optical Coherence Tomography Angiography to Detect Glaucoma and Anterior Ischemic Optic Neuropathy.

Glaucoma and non-arteritic anterior ischemic optic neuropathy (NAION) are optic neuropathies that can both lead to irreversible blindness. Several studies have compared optical coherence tomography angiography (OCTA) findings in glaucoma and NAION in the presence of similar functional and structural damages with contradictory results. The goal of this study was to use a deep learning system to differentiate OCTA in glaucoma and NAION. Sixty eyes with glaucoma (including primary open angle glaucoma, angle-closure glaucoma, normal tension glaucoma, pigmentary glaucoma, pseudoexfoliative glaucoma and juvenile glaucoma), thirty eyes with atrophic NAION and forty control eyes (NC) were included. All patients underwent OCTA imaging and automatic segmentation was used to analyze the macular superficial capillary plexus (SCP) and the radial peripapillary capillary (RPC) plexus. We used the classic convolutional neural network (CNN) architecture of ResNet50. Attribution maps were obtained using the "Integrated Gradients" method. The best performances were obtained with the SCP + RPC model achieving a mean area under the receiver operating characteristics curve (ROC AUC) of 0.94 (95% CI 0.92-0.96) for glaucoma, 0.90 (95% CI 0.86-0.94) for NAION and 0.96 (95% CI 0.96-0.97) for NC. This study shows that deep learning architecture can classify NAION, glaucoma and normal OCTA images with a good diagnostic performance and may outperform the specialist assessment.

Optical Coherence Tomography Angiography in Neurodegenerative Disorders.

Retinal microcirculation shares similar features with cerebral small blood vessels. Thus, the retina may be considered an accessible ‘window’ to detect the microvascular damage occurring in the setting of neurodegenerative disorders. Optical coherence tomography angiography (OCT-A) is a non-invasive imaging modality providing depth resolved images of blood flow in the retina, choroid, and optic nerve. In this review, we summarize the current literature on the application of OCT-A in glaucoma and central nervous system conditions such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Future directions aiming at evaluating whether OCT-A can be an additional biomarker for the early diagnosis and monitoring of neurodegenerative disorders are also discussed.

A Review of OCT Angiography in Glaucoma

ABSTRACTThere is growing evidence that vascular dysfunction plays a role in the pathogenesis of glaucoma. The details of this relationship have remained elusive partially due to limitations in our ability to assess blood flow in the optic nerve. Optical coherence tomography angiography (OCTA) has emerged as a promising new technology well positioned to become the first clinically suitable test of optic nerve perfusion. OCTA uses the motion of red blood cells as an intrinsic contrast agent to create reproducible images of microvascular networks rapidly and non-invasively. A significant body of research regarding the use of OCTA in glaucoma has emerged in recent years. This review aims to provide an overview of the basic principles underlying OCTA technology, summarize the current literature regarding the application of OCTA in the management of glaucoma, and address the role of OCTA in explicating the vascular pathogenesis of glaucoma.

Optical coherence tomography angiography in glaucoma.

Optical coherence tomography angiography (OCTA) studies have demonstrated reduced microcirculation in the superficial optic nerve, peripapillary retina, and the macula of glaucoma patients. The scope of this review is to outline recent studies using OCTA in glaucoma and highlight how OCTA may help improve diagnosis and follow-up in glaucoma patients. OCTA studies have provided evidence of vascular changes in the optic nerve head, peripapillary, and macula region in glaucoma in comparison to glaucoma suspects and normal eyes. Additionally, OCTA can detect longitudinal reduction of peripapillary and macula vessel density in glaucoma patients. It remains unclear whether the reduced microcirculation in glaucoma patients induces the neuronal damage or arises through reduced circulation requirements in damaged tissue. OCTA is a novel imaging modality that has great potential to enhance our understanding of glaucoma and to improve our ability to detect and treat it.

Optical Coherence Tomography Angiography in Glaucoma.

Optical coherence tomography angiography (OCTA) comprises different OCT-based technologies developed for non-invasive assessment and measurement of optic nerve head and retinal perfusion. Currently the most clinically established approach is based on the split spectrum amplitude decorrelation algorithm, which detects moving red blood cells and eliminates all other information. The two main clinical fields in which OCTA offers clinically useful information are investigation of the macular retina (e.g. in macular degeneration and diabetic macular disease) and glaucoma. For glaucoma, the optic nerve head and the peripapillary retinal perfusion in the retinal nerve fiber layer, and the superficial perifoveal macular vasculature are the areas of interest. This review provides a comprehensive summary of the most important current and potential future applications of OCTA in glaucoma, but it does not address the nonglaucomatous optic nerve head or peripapillary and macular diseases.

Potential applications of optical coherence tomography angiography in glaucoma.

Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging modality that allows assessment of the retinal and choroidal vasculature. The scope of this review is to summarize recent studies using OCTA in glaucoma and highlight potential applications of this new technology in the field of glaucoma. OCTA studies have shown that retinal vascular changes may not develop solely as a result of advanced glaucoma damage. OCTA-derived measurements have provided evidence for lower retinal vascular densities at the optic nerve head, peripapillary and macula in preperimetric-glaucoma and early-glaucoma, as well as, in more advanced glaucoma, in comparison to with normal eyes. OCTA is a novel imaging modality that has already started to expand our knowledge base regarding the role of ocular blood flow in glaucoma. Future studies will better elucidate the role of OCTA-derived measurements in clinical practice, research, and clinical trials in glaucoma.