Comparison of Optical Coherence Tomography Angiography to Indocyanine Green Angiography and Slit Lamp Photography for Corneal Vascularization in an Animal Model

Stanzel, Tisha Prabriputaloong; Devarajan, Kavya; Lwin, Nyein Chan; Yam, Gary Hin Fai; Schmetterer, Leopold; Ang, Marcus

doi:10.1038/s41598-018-29752-5

Cited by 42 publications

(49 citation statements)

References 51 publications

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“…By shining a thin sheet of light into the eye, an in vivo stereoscopic evaluation of the pathological changes of the cornea, conjunctiva and other anterior segment tissues can be performed by SLB [9]. However, the limited magnification and poor spatial resolution of traditional SLB make it difficult to visualize more detailed pathological structures and perform accurate biometric measurements [10][11][12]. Fluorescein stain could stain stroma while leaving the intact epithelium with a specific fluorescein dye, thereby demarcating the location and area of the epithelial loss in ocular surface diseases, on a relative macro scale as well [13].…”

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confidence: 99%

Multi-modal Anterior Eye Imager Combining Ultra-High Resolution OCT and Microvascular Imaging for Structural and Functional Evaluation of the Human Eye

et al. 2020

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To establish complementary information for the diagnosis and evaluation of ocular surface diseases, we developed a multi-modal, non-invasive optical imaging platform by combining ultra-high resolution optical coherence tomography (UHR-OCT) with a microvascular imaging system based on slit-lamp biomicroscopy. Our customized UHR-OCT module achieves an axial resolution of ≈2.9 µm in corneal tissue with a broadband light source and an A-line acquisition rate of 24 kHz with a line array CCD camera. The microvascular imaging module has a lateral resolution of 3.5 µm under maximum magnification of ≈187.5× with an imaging rate of 60 frames/s, which is sufficient to image the conjunctival vessel network and record the movement trajectory of clusters of red blood cells. By combining the imaging optical paths of different modules, our customized multi-modal anterior eye imaging platform is capable of performing real-time cross-sectional UHR-OCT imaging of the anterior eye, conjunctival vessel network imaging, high-resolution conjunctival blood flow videography, fluorescein staining and traditional slit-lamp imaging on a single device. With self-developed software, a conjunctival vessel network image and blood flow videography were further analyzed to acquire quantitative morphological and hemodynamics parameters, including vessel fractal dimensions, blood flow velocity and vessel diameters. The ability of our multi-modal anterior eye imager to provide both structural and functional information for ophthalmic clinical applications was demonstrated on a healthy human subject and a keratitis patient. evaluation of ocular surface diseases, different imaging modalities are usually applied in ophthalmic clinics to provide multi-modal and multi-dimensional images [7,8].Slit-lamp biomicroscopy (SLB) is the gold standard for routine ophthalmic examinations. By shining a thin sheet of light into the eye, an in vivo stereoscopic evaluation of the pathological changes of the cornea, conjunctiva and other anterior segment tissues can be performed by SLB [9]. However, the limited magnification and poor spatial resolution of traditional SLB make it difficult to visualize more detailed pathological structures and perform accurate biometric measurements [10][11][12]. Fluorescein stain could stain stroma while leaving the intact epithelium with a specific fluorescein dye, thereby demarcating the location and area of the epithelial loss in ocular surface diseases, on a relative macro scale as well [13]. Developed in the 1990s, optical coherence tomography (OCT) has revolutionized the field of ophthalmology and vision science with its non-contact, non-invasive and high-resolution nature and become one of the prominent diagnostic tools in offering cross-sectional tissue imaging [14][15][16]. Applications of OCT for in vivo human eye imaging have been widely demonstrated in the literature [17][18][19][20][21][22][23][24][25][26][27][28]. With ever-improving techniques in broadband light sources, ultra-high resolution OCT (UHR-OCT) has achieved m...

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Multi-modal Anterior Eye Imager Combining Ultra-High Resolution OCT and Microvascular Imaging for Structural and Functional Evaluation of the Human Eye

et al. 2020

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“…As a contactless and non-invasive procedure, OCTA has recently found clinical application, especially in ophthalmology, since it allows generation of high-resolution images of the perfusion of the anterior eye segment, choroid and retina. Several experimental and clinical studies have shown the reliability and validity of OCTA for monitoring microvascular perfusion of the eye [28][29][30][31] . In the present study, OCTA was used successfully to evaluate the sublingual microcirculation in detail.…”

Section: Discussionmentioning

confidence: 99%

Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study

Heßler

Nelis

Ertmer

et al. 2020

Sci Rep

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Microcirculatory disorders are crucial in pathophysiology of organ dysfunction in critical illness. Evaluation of sublingual microcirculation is not routinely conducted in daily practice due to timeconsuming analysis and susceptibility to artifacts. We investigated the suitability of optical coherence tomography angiography (octA) for contactless evaluation of sublingual microcirculation. Sublingual microcirculation was imaged in 10 healthy volunteers, using an OCTA device and an incident dark field (IDF) illumination microscopy (current gold standard). OCTA images were analyzed with regard to flow density and perfused vessel density (PVD byoctA). IDF videos were analyzed following current recommendations. Flow density was automatically extracted from OCTA images (whole en face 48.9% [43.2; 54.5]; central ring 52.6% [43.6; 60.6]). PVD byoctA did not differ from the PVD calculated from IDF videos (PVD byoctA 18.6 mm/mm² [18.0; 21.7]) vs. PVD byIDF 21.0 mm/mm² [17.5; 22.9]; p = 0.430). Analysis according to Bland-Altman revealed a mean bias of 0.95 mm/mm² (95% Confidence interval −1.34 to 3.25) between PVD byoctA and PVD byIDF with limits of agreement of −5.34 to 7.24 mm/mm². This study is the first to demonstrate the suitability of OCTA for evaluating sublingual microcirculation. comparison of the perfused vessel density between methods showed a plausible level of agreement. In recent years, research has highlighted the importance of the microcirculation (vessels smaller than 100 μm) in the pathophysiology of diseases and organ dysfunction in critical illness. It is known that blood flow in the microcirculation is often impaired in critically ill patients and altered blood flow in the microcirculation is associated with outcome 1-6. A decoupling of macro-and microcirculation ("loss of hemodynamic coherence"), as can occur, for example, in advanced stages of septic shock is of particular interest here 7. In such conditions, macrohemodynamic parameters such as cardiac output and perfusion pressure are no longer indicative of perfusion in the microcirculation. The aim of hemodynamic therapy should therefore be restoration not only of the macrocirculation but also the microcirculation 7. Hence the demand for bedside methods to monitor the microcirculation. Bedside analysis of the microcirculation became possible with the introduction of modern handheld video microscopes using sidestream dark field (SDF) imaging or incident dark field (IDF) illumination technology 8-10. Unfortunately, the analysis of the microcirculation has not yet become established in routine clinical practice, as video microscopy of capillary blood flow has so far been limited by artifacts (e.g.

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“…The first obvious application is the objective delineation and potentially quantification of corneal vascularisation (Figure ) . Importantly, OCT‐A of corneal neovascularisation has been validated against histology in animal models, whereas this has not been achieved with posterior segment OCT‐A. As the physiologically normal cornea is essentially avascular and receives oxygen from the air and the aqueous humour, pathological corneal vascularisation affects corneal transparency.…”

Section: Oct‐a Of the Anterior Segmentmentioning

confidence: 99%

Future clinical applicability of optical coherence tomography angiography

Chua

Tan

Ang

et al. 2019

Clinical and Experimental Optometry

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Optical coherence tomography angiography (OCT-A) is an emerging technology that allows for the non-invasive imaging of the ocular microvasculature. Despite the wealth of observations and numerous research studies illustrating the potential clinical uses of OCT-A, this technique is currently rarely used in routine clinical settings. In this review, technical and clinical aspects of OCT-A imaging are discussed, and the future clinical potential of OCT-A is considered. An understanding of the basic principles and limitations of OCT-A technology will better inform clinicians of its future potential in the diagnosis and management of ocular diseases.

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Comparison of Optical Coherence Tomography Angiography to Indocyanine Green Angiography and Slit Lamp Photography for Corneal Vascularization in an Animal Model

Cited by 42 publications

References 51 publications

Multi-modal Anterior Eye Imager Combining Ultra-High Resolution OCT and Microvascular Imaging for Structural and Functional Evaluation of the Human Eye

Multi-modal Anterior Eye Imager Combining Ultra-High Resolution OCT and Microvascular Imaging for Structural and Functional Evaluation of the Human Eye

Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study

Future clinical applicability of optical coherence tomography angiography

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