scholarly journals A pilot study investigating anterior segment optical coherence tomography angiography as a non-invasive tool in evaluating corneal vascularisation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hon Shing Ong ◽  
Kai Yuan Tey ◽  
Mengyuan Ke ◽  
Bingyao Tan ◽  
Jacqueline Chua ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Objective Assessment ◽  
Anterior Segment ◽  
Optical Coherence ◽  
Non Invasive ◽  
Imaging Tool ◽  
Model Study ◽  
Animal Model Study ◽  
Endothelial Growth Factor

AbstractThe current assessment of corneal vascularisation (CV) relies on slit-lamp examination, which may be subjective. Dye-based angiographies, like indocyanine green angiography (ICGA), allows for good visualisation of anterior segment blood vessels. However, ICGA is invasive and can be associated with systemic adverse effects. Anterior segment optical coherence tomography angiography (AS-OCTA) is a non-invasive tool that has been shown to successfully delineate CV. However, there are no previous studies that have reported if AS-OCTA can determine CV stage and activity. We used an established CV model in rabbits to examine serial AS-OCTA scans of CV development and regression following treatment with anti-vascular endothelial growth factor. We compared AS-OCTA derived vascular measurements to that of ICGA determined vessel leakage and CV staging. Our results showed that AS-OCTA vessel densities and vessel branch area significantly correlated with the severity of CV based on ICGA (all p ≤ 0.05). We also found that AS-OCTA vessel densities correlated with ICGA vessel leakage time, following an inverse linear relationship (r2 = − 0.726, p < 0.01). Changes in aqueous levels of CXCL-12 and PIGF cytokines significantly correlated with AS-OCTA vessel densities (r2 = 0.736 and r2 = 0.731 respectively, all p < 0.05). In summary, we found that AS-OCTA derived vessel parameters may be useful for assessing CV severity, while vessel density correlates with CV activity and leakage. Thus, our pilot animal model study suggests that AS-OCTA may be a useful non-invasive imaging tool to provide objective assessment of CV to examine progression or response in treatment, which requires confirmation in clinical studies.

scholarly journals Optical coherence tomography angiography in diabetic retinopathy: a review of current applications

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Kai Yuan Tey ◽  
Kelvin Teo ◽  
Anna C. S. Tan ◽  
Kavya Devarajan ◽  
Bingyao Tan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Optical Coherence Tomography Angiography ◽  
Vision Loss ◽  
Imaging Modality ◽  
Anterior Segment ◽  
Foveal Avascular Zone ◽  
Imaging Method ◽  
Optical Coherence ◽  
Non Invasive

Abstract Background Diabetic retinopathy (DR) is a leading cause of vision loss in adults. Currently, the standard imaging technique to monitor and prognosticate DR and diabetic maculopathy is dye-based angiography. With the introduction of optical coherence tomography angiography (OCTA), it may serve as a potential rapid, non-invasive imaging modality as an adjunct. Main text Recent studies on the role of OCTA in DR include the use of vascular parameters e.g., vessel density, intercapillary spacing, vessel diameter index, length of vessels based on skeletonised OCTA, the total length of vessels, vascular architecture and area of the foveal avascular zone. These quantitative measures may be able to detect changes with the severity and progress of DR for clinical research. OCTA may also serve as a non-invasive imaging method to detect diabetic macula ischemia, which may help predict visual prognosis. However, there are many limitations of OCTA in DR, such as difficulty in segmentation between superficial and deep capillary plexus; and its use in diabetic macula edema where the presence of cystic spaces may affect image results. Future applications of OCTA in the anterior segment include detection of anterior segment ischemia and iris neovascularisation associated with proliferative DR and risk of neovascular glaucoma. Conclusion OCTA may potentially serve as a useful non-invasive imaging tool in the diagnosis and monitoring of diabetic retinopathy and maculopathy in the future. Future studies may demonstrate how quantitative OCTA measures may have a role in detecting early retinal changes in patients with diabetes.

Results of the project «Optimization of the process of obtaining the service OCT “ (project implementation period 20.06.2019–08.10.2019)

2021 ◽  
pp. 29-37
Author(s):  
Irina Aleksandrovna Rakitina ◽  
Alfiya Gumyarovna Iskhakova ◽  
Evgeny Andreevich Zamytsky ◽  
Marina Vladimirovna Makolina ◽  
Farida Sagitovna Goleeva ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Segment ◽  
Contact Method ◽  
Optical Coherence ◽  
Non Invasive ◽  
Risk Of Injury ◽  
Eye Tissues ◽  
Implementation Period ◽  
Project Optimization ◽  
Theoretical Foundations

Optical Coherence Tomography (OCT) is a modern, highly accurate, non-invasive study of various eye structures. OCT is a non-contact method that allows a specialist to visualize eye tissue with a very high resolution (1–15 microns), the accuracy of which is comparable to microscopic examination. The theoretical foundations of the OCT method were developed in 1995 by the American ophthalmologist K. Pulafito, and already in 1996–1997 Carl Zeiss Meditec introduced the first device for optical coherence tomography into clinical practice. Today, OCT devices are used to diagnose various diseases of the fundus and anterior segment of the eye. Due to the maximum accuracy, the method of light scanning greatly simplifies the diagnosis of pathologies of the organs of vision, regardless of the cause of their occurrence and the stage of the course. In terms of information content, the technique is not inferior to histology, but the advantage of OCT is the absence of the risk of injury to the eye tissues [1, 2].

Optical Coherence Tomography Angiography for Anterior Segment Vasculature Imaging

Ophthalmology ◽  
2015 ◽  
Vol 122 (9) ◽  
pp. 1740-1747 ◽  
Author(s):  
Marcus Ang ◽  
Dawn A. Sim ◽  
Pearse A. Keane ◽  
Chelvin C.A. Sng ◽  
Catherine A. Egan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Anterior Segment ◽  
Optical Coherence

scholarly journals Deep learning algorithms to isolate and quantify the structures of the anterior segment in optical coherence tomography images

2020 ◽  
pp. bjophthalmol-2019-315723
Author(s):  
Tan Hung Pham ◽  
Sripad Krishna Devalla ◽  
Aloysius Ang ◽  
Zhi-Da Soh ◽  
Alexandre H Thiery ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Objective Assessment ◽  
Anterior Segment ◽  
Angle Closure Glaucoma ◽  
Training Data ◽  
Angle Closure ◽  
Optical Coherence ◽  
Segmentation Approach ◽  
Reliable Quantification ◽  
The Given

Background/AimsAccurate isolation and quantification of intraocular dimensions in the anterior segment (AS) of the eye using optical coherence tomography (OCT) images is important in the diagnosis and treatment of many eye diseases, especially angle-closure glaucoma.MethodIn this study, we developed a deep convolutional neural network (DCNN) for the localisation of the scleral spur; moreover, we introduced an information-rich segmentation approach for this localisation problem. An ensemble of DCNNs for the segmentation of AS structures (iris, corneosclera shell adn anterior chamber) was developed. Based on the results of two previous processes, an algorithm to automatically quantify clinically important measurements were created. 200 images from 58 patients (100 eyes) were used for testing.ResultsWith limited training data, the DCNN was able to detect the scleral spur on unseen anterior segment optical coherence tomography (ASOCT) images as accurately as an experienced ophthalmologist on the given test dataset and simultaneously isolated the AS structures with a Dice coefficient of 95.7%. We then automatically extracted eight clinically relevant ASOCT measurements and proposed an automated quality check process that asserts the reliability of these measurements. When combined with an OCT machine capable of imaging multiple radial sections, the algorithms can provide a more complete objective assessment. The total segmentation and measurement time for a single scan is less than 2 s.ConclusionThis is an essential step towards providing a robust automated framework for reliable quantification of ASOCT scans, for applications in the diagnosis and management of angle-closure glaucoma.

scholarly journals Optical Coherence Tomography Angiography Imaging to monitor Anti-VEGF treatment of Corneal Vascularization in a Rabbit Model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kavya Devarajan ◽  
Hon Shing Ong ◽  
Nyein C. Lwin ◽  
Jacqueline Chua ◽  
Leopold Schmetterer ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Imaging Technique ◽  
Anterior Segment ◽  
Rabbit Model ◽  
Saline Group ◽  
Optical Coherence ◽  
Conjunctival Injection ◽  
Anti Vegf ◽  
Significant Difference

AbstractOptical coherence tomography angiography (OCTA) is a well-established non-invasive retinal vascular imaging technique. It has been recently adapted to image the anterior segment and has shown good potential to image corneal vascularisation. The purpose of the study is to evaluate the usefulness of OCTA to monitor regression of corneal vessels following anti-VEGF (vascular endothelial growth factor) treatment using a previously established corneal vascularisation rabbit model. The regression of vessels following the treatment with aflibercept and ranibizumab anti-VEGFs using both topical instillation and sub-conjunctival injection was quantified using OCTA and compared with ICGA (indocyanine green angiography). Overall vessel density measurements using OCTA showed good correlation (r = 0.988, p < 0.001) with ICGA, with no significant difference between the two treatment groups (p = 0.795). It was also shown that OCTA provided good repeatability outcomes of the quantitative measurements. Using Bland-Altman plots, vessel growth density values between anti-VEGF treatments were compared to control saline group. It was observed that aflibercept provided longer lasting effect than ranibizumab. We also observed that in both drugs, the topical route of administration topical provided longer regression outcomes compared to one-time sub-conjunctival injection. Thereby, with this pilot study, it was demonstrated that OCTA is a reliable imaging technique to follow-up and monitor corneal vascularisation and its treatment quantitatively.

scholarly journals Optical coherence tomography angiography of foveal neovascularisation in proliferative diabetic retinopathy

2019 ◽  
Vol 12 (8) ◽  
pp. e230382
Author(s):  
Deven Dhurandhar ◽  
Padmaja Kumari Rani
Keyword(s):  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Proliferative Diabetic Retinopathy ◽  
Optical Coherence Tomography Angiography ◽  
Imaging Modality ◽  
Diabetic Macular Oedema ◽  
Hypertensive Retinopathy ◽  
Optical Coherence ◽  
Non Invasive

A 52-year-old man, a known case of type 2 diabetes mellitus and hypertension, who presented to us with bilateral diminution of vision since 1 year. He was diagnosed as a case of bilateral proliferative diabetic retinopathy and hypertensive retinopathy. A non-invasive imaging modality, optical coherence tomography angiography (OCTA), detected foveal neovascularisation in a background of diffuse diabetic macular oedema which would have been obscured by other investigations like fluorescein angiography.

scholarly journals Optical Coherence Tomography Angiography of Iris Nevus: A Case Report

2016 ◽  
Vol 7 (3) ◽  
pp. 450-456 ◽  
Author(s):  
Davide Allegrini ◽  
Giovanni Montesano ◽  
Alfredo Pece
Keyword(s):  
Optical Coherence Tomography ◽  
Case Report ◽  
Optical Coherence Tomography Angiography ◽  
Anterior Segment ◽  
Ultrasound Biomicroscopy ◽  
Vascular Network ◽  
Optical Coherence ◽  
Early Phases ◽  
Iris Nevus

Iris nevus is common: 6% of patients with suspected iris melanoma have lesions other than melanoma, and 36% of them are nevi. Iris nevus turns into melanoma in approximately 8% of cases at a mean of 15 years. This case report provides the first description of an iris tumor examined with iris optical coherence tomography angiography (OCTA) compared to iris fluorescein angiography (IFA). A 60-year-old man with a diagnosis of iris nevus in the left eye was referred to our department for IFA and iris OCTA. The iris vasculature in IFA was visible only in the early phases, but not clearly. OCTA, however, gave visualization of the vascular network and very precisely defined the vessels of the whole lesion, except for the pupillary portion, which was masked by superficial pigment accumulations. IFA and iris OCTA can add information about the vascular architecture compared to slit-lamp biomicroscopy, ultrasound biomicroscopy, and anterior-segment OCT. However, IFA is time-consuming and invasive and can – very occasionally – cause serious adverse reactions. In contrast, OCTA defines the texture of the iris vasculature better. In conclusion, OCTA is a new method, easy to execute, needing no dye injection, and provides useful information on the vascular network of iris lesions. It could therefore be helpful in the diagnosis and follow-up of these lesions.

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