Dao-Yi Yu

Dao-Yi Yu
University of Western Australia | UWA · Lions Eye Institute

About

260
Publications
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8,672
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Publications

Publications (260)
Article
Full-text available
Purpose To describe pulsations of the retinal arteries detected in the course of evaluation of an exudative non-pulsatile retinal arterial macroaneurysm using near infra-red reflectance videography. Observations A 68-year-old patient underwent slit lamp examination, color retinal imaging, optical coherence tomography, fluorescein videography, shor...
Article
Full-text available
PurposeTo compare the retinal vascular pulsatile characteristics in subjects with normal (ICPn) and high (ICPh) intracranial pressure and quantify the interactions between intraocular pressure, intracranial pressure, and retinal vascular pulse amplitude in the Fourier domain.Materials and methodsTwenty-one subjects were examined using modified phot...
Article
Full-text available
Purpose: To investigate differences in alpha smooth muscle actin (αSMA) expression and parafoveal blood flow pathways in diabetic retinopathy (DR). Methods: Human donor eyes from healthy subjects (n = 8), patients with diabetes but no DR (DR-; n = 7), and patients with clinical DR (DR+; n = 13) were perfusion labeled with antibodies targeting αS...
Article
Microaneurysms are biomarkers of microvascular injury in diabetic retinopathy (DR). Impaired retinal capillary perfusion is a critical pathogenic mechanism in the development of microvascular abnormalities. Targeting fundamental molecular disturbances due to capillary nonperfusion, such as increased vascular endothelial growth factor expression, do...
Article
Full-text available
Purpose: To use high-resolution histology to define the associations between microaneurysms, capillary diameter and capillary density alterations in diabetic retinopathy (DR). Methods: Quantitative comparisons of microaneurysm number, capillary density and capillary diameter were performed between eight human donor eyes with nonproliferative DR...
Article
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Purpose: To determine the fidelity of optical coherence tomography angiography (OCTA) techniques by direct comparison of the retinal capillary network images obtained from the same region as imaged by OCTA and high-resolution confocal microscope. Method: Ten porcine eyes were perfused with red blood cells for OCTA image acquisition from the area...
Chapter
The retina is a thin layer of neural tissue lining the posterior portion of the eye and is often considered an outpost of the brain. Ninety percentage of all sensory signals integrated in the brain are of visual origin. The retina contains light-sensitive photoreceptor cells, four basic classes of neurons and glial cells. Unlike other sensory stimu...
Chapter
Rational management of macular diseases should be based on a clear understanding of the contributing pathophysiological mechanisms. The treatment of macular diseases has progressed dramatically over the past few decades, as clinical and experimental studies have led to an enhanced understanding of disease pathogenesis as well as to the development...
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Purpose: To use structural criteria to reconcile the three-dimensional organization and connectivity of the parafoveal microvasculature. Methods: The parafoveal microvasculature was perfused and labeled in 16 normal human donor eyes for lectin, alpha smooth muscle actin, and filamentous actin. Established structural criteria gathered using confo...
Article
Astrocytes are critical for the maintenance of retinal ganglion cell (RGC) axonal function and viability, and form a key component of the functional neurovascular unit. Recently, we described the quantitative properties of astrocytes in relation to the capillary distributions in optic nerve laminar regions. Here, we provide a quantitative analysis...
Article
Objective To investigate the association between optic disc hemorrhage (ODH) recurrence, location and visual field (VF) progression. Design Prospective observational study. Participants Patients with bilateral glaucoma, or unilateral glaucoma with a fellow glaucoma suspect eye were enrolled. Methods Patients had optic disc photography every 3 mo...
Article
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Pulse wave attenuation characteristics reflect compliance and resistance properties of the vessel wall as well as initial pulse generation factors. Recently, it has become possible to measure and map the retinal vessel wall pulse wave amplitudes. Predictable pulse wave amplitude distribution may allow inferences to be made concerning vascular compl...
Article
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Purpose: The purpose of this study was to use three-dimensional confocal microscopy to quantify the spatial patterns of capillary network alterations in nonproliferative diabetic retinopathy (NPDR). Methods: The retinal microvasculature was perfusion-labelled in seven normal human donor eyes and six age-matched donor eyes with NPDR. The peripapi...
Article
Purpose: We studied the topographic distribution of contractile protein in different orders of the human macular microvasculature to further understanding of the sites for capillary blood flow regulation. Methods: Nine donor eyes from eight donors were cannulated at the central retinal artery and perfusion labeled for alpha smooth muscle actin (...
Article
Importance: A new method to help diagnose suspected cyclodialysis clefts. Background: To study the use of trypan blue stained aqueous flow patterns in diagnosing causes of hypotony where cyclodialysis clefts were suspected. Design: A case series in a tertiary care centre PARTICIPANTS: 10 subjects presenting with persistent hypotony and retinal...
Chapter
Glaucoma is an aetiologically complex disorder of optic neuropathies. Stressors related to age and intraocular pressure lead to progressive degeneration of the retinal ganglion cells. Clinically ophthalmic testing has been used to identify and quantify the functional and/or structural defects for diagnosis, assessing progression and therapeutic out...
Chapter
Glaucoma is a disease of the optic nerve, wherein the anterior part of the nerve, the optic disk, undergoes posterior distortion (cupping and excavation) along with loss of the nerve fibres. This leads to peripheral and finally total visual field loss. The major risk factor is elevated IOP, which along with cerebrospinal fluid pressure (CSFP) large...
Article
The central role of the cardiovascular system is to maintain adequate capillary perfusion. The spatially and temporally heterogeneous nature of capillary perfusion has been reported in some organs. However, such heterogeneous perfusion properties have not been sufficiently explored in the retina. Arguably, spatial and temporal heterogeneity of capi...
Article
Purpose: To define the three-dimensional topologic organization of the human peripapillary capillary plexuses in order to better understand the hemodynamic characteristics of this retinal circulation. Methods: The retinal microvasculature was perfusion labeled in five normal human donor eyes, and optical stacks were collected from regions immedi...
Chapter
The oxygen supply to the retina in man and most mammals is derived from both the retinal and choroidal circulations. However, some mammals have only a partially vascularized retina, and some have a completely avascular retina. Here we contrast the retinal oxygen levels during systemic hyperoxia in a fully vascularized retina (rat), a partially vasc...
Article
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We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo. This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher‐resolution OCM...
Article
The mechanisms of neuronal degeneration and associated acute alterations in intraretinal cytokine and protein levels remain poorly understood in variable ischaemic retinopathies such as in branch retinal vein occlusion (BRVO). Herein we investigate neuronal damage and alterations in retinal cytokines and proteins in a pig model of acute BRVO. Twelv...
Article
Purpose: To quantify associations between microvascular density and retinal ganglion cell (RGC) axonal volume in the laminar compartments of the human optic nerve head (ONH). Methods: Eleven normal human ONHs were evaluated. Antibodies were used to label the vascular endothelium (factor VIII-related antigen/von Willebrand factor antibody) and RG...
Article
The aim was to quantitatively compare retinal vascular detail as seen on optical coherence tomography angiography (OCTA) and matched histology in the human eye. 13 normal human donor eyes were used. The central retinal artery was cannulated after which human packed red blood cells were perfused through the retinal vasculature. Retinal vessels were...
Article
Purpose: To use the capillary-free zone along retinal arteries, a physiologic area of superficial avascularization, as an anatomic paradigm to investigate the reliability of optical coherence tomographic angiography (OCTA) for visualizing the deep retinal circulation. Design: Validity analysis and laboratory investigation. Methods: Five normal...
Article
Purpose: To precisely quantify the macular microvasculature density using microperfusion and labeling techniques in human donor eyes. Such information may be useful in understanding the role of the macular microvasculature in coping with the metabolic requirements of the neurons in this densely packed region, and provide a reference point for clin...
Article
Optic nerve head (ONH) drusen is a condition of unresolved aetiology with an incidence of approximately 3.4 per 1000 in the general population.¹ Presumably, similar to glaucoma, the predominant site of retinal ganglion cell (RGC) axonal injury due to disc drusen occurs at the ONH, where laminated, calcified aggregates of hyaline-like material are f...
Article
Purpose: The iris allows effective delivery of nutrients into the aqueous humor supplying the surrounded avascular tissues. However, possible underlying mechanisms of the iris vasculature have not been well established. This study aims to quantitatively assess the human iris vascular network, endothelial cell morphometries, and characterize endoth...
Article
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Purpose: To explore the potential relationship between optic disc haemorrhage, venous pulsation pressure (VPP), ocular perfusion pressures and visual field change in glaucomatous and glaucoma suspect eyes. Materials and methods: This prospective observational study examined 155 open angle glaucoma or glaucoma suspect eyes from 78 patients over 5...
Data
Dataset for statistics. 5 year clinical data used for statistical analysis. (CSV)
Article
Purpose: The prevailing view is that the human retina is supplied by the central retinal artery (CRA), the short posterior ciliary arteries (SPCAs) support the choroid, and both the CRA and the SPCAs are so-called "end artery" systems. In this study, we investigate whether vascular connections among the retina, choroid, and the optic nerve head (O...
Article
Full-text available
Primary angle-closure glaucoma (PACG) is a common cause of blindness. Angle closure is a fundamental pathologic process in PAGC. With the development of imaging devices for the anterior segment of the eye, a better understanding of the pathogenesis of angle closure has been reached. Aside from pupillary block and plateau iris, multiple-mechanisms a...
Article
Retinal vein pulsation was first noted soon after the invention of the ophthalmoscope 170 years ago and was seen to change with cerebrospinal fluid pressure (CSFP) variation in the 1920s. The classical explanation for vein pulsation was that the cardiac cycle induced systolic peak in intraocular pressure (IOP) tended to intermittently collapse the...
Article
Purpose: To evaluate the quantitative characteristics of the radial peripapillary capillary (RPC) network in glaucoma, glaucoma suspect and normal eyes using speckle variance optical coherence tomography angiography (OCT-A). To determine correlations between RPC density, nerve fibre layer (NFL) thickness and visual field indices. Design: Cross s...
Article
Purpose: To determine whether vascular tone of isolated porcine retinal veins can be modulated by tissue-generated vasoactive factors such as endothelin-1 and adenosine. Such information may be useful in understanding the role of the retinal veins in regulating blood flow, and also provide a model for investigating new hypotheses suggesting a role...
Article
The relationship between structural characteristics of the optic nerve head and venous pulsations in the human eye remain unknown. Using photoplethysmographic techniques we investigated whether properties of the human retinal veins and their surrounding structures influence venous pulsation. 448 locations of venous pulsation were analysed from 26 n...
Article
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Purpose: To explore whether alterations in intraocular pressure (IOP) affect vein pulsation properties using ophthalmodynamometric measures of vein pulsation pressure. Patients and methods: Glaucoma patients had two retinal vein pulsation pressure (VPP) measurements from upper and lower hemiveins performed by ophthalmodynamometry at least 3 mont...
Article
Recently we reported studies of the iris microvasculature and its endothelial cells using intra-luminal micro-perfusion, fixation, and silver staining, suggesting that the iris vascular endothelium may be crucial for maintaining homeostasis in the ocular anterior segment. Here we present information regarding the intracellular structure and cell ju...
Article
Full-text available
Glaucoma is one of the leading causes of blindness in the developed world. It is a progressive optic neuropathy where structural loss of retinal ganglion cell (RGC) axons corresponds with functional visual field defect. Glaucoma is distinguished from other optic neuropathies by its selective loss of RGC axons. Superior and inferior peripheral nerve...
Article
Full-text available
Radial peripapillary capillaries (RPCs) comprise a unique network of capillary beds within the retinal nerve fibre layer (RNFL) and play a critical role in satisfying the nutritional requirements of retinal ganglion cell (RGC) axons. Understanding the topographical and morphological characteristics of these networks through in vivo techniques may i...
Article
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To demonstrate the utility of speckle variance optical coherence tomography (svOCT), a noninvasive angiographic technique, for evaluating the foveal vasculature. Twelve normal human eyes were imaged with svOCT (1060-nm, 100-kHz custom-built system) and fluorescein angiography (FA; Topcon TRC-50DX with 5.0 megapixel resolution camera). Manual tracin...
Article
The purpose of this study was to correlate human retinal capillary network information derived from a prototype speckle variance optical coherence tomography (svOCT) device with histology to determine the utility of this instrument for quantitative angiography. A retina location 3 mm superior to the optic disk was imaged with svOCT in 14 healthy hu...
Article
Cannabinoids have been reported to mediate changes in vascular resistance through endothelial receptor targets. We examined involvement of the endothelium in cannabinoid-mediated vasoactive responses in resistance arterioles of the retina. Vascular responses to both intraluminal (IL) and extraluminal (EL) administration of the atypical cannabinoid,...
Article
Retinal capillary networks are critically linked to neuronal health and disease. The ability to perform accurate in vivo examination of human retinal capillary networks is therefore valuable for studying mechanisms that govern retinal homeostasis and retinal vascular diseases. Speckle variance optical coherence tomography (svOCT) is a non-invasive...
Article
Full-text available
Cerebrospinal fluid pressure (CSFP) interacts with intraocular pressure (IOP) and blood pressure to exert a major influence upon the eye, particularly the optic nerve head region. There is increased interest regarding the influence of CSFP upon disorders affecting this region, in particular glaucoma and idiopathic intracranial hypertension. Additio...
Article
This report describes a novel, non-invasive and label-free optical imaging technique, speckle variance optical coherence tomography (svOCT), for visualising blood flow within human retinal capillary networks. This imaging system uses a custom-built swept source OCT system operating at a line rate of 100 kHz. Real-time processing and visualisation i...
Article
The roles of the iris microvasculature have been increasingly recognised in the pathogenesis of glaucoma and cataract; however limited information exists regarding the iris microvasculature and its endothelium. This study quantitatively assessed the iris microvascular network and its endothelium using intra-luminal micro-perfusion, fixation, and st...
Article
Full-text available
Retinal venous pulsation detection is a subjective sign, which varies in elevated intracranial pressure, venous obstruction and glaucoma. To date no method can objectively measure and identify pulsating regions. Using high resolution video-recordings of the optic disk and retina we measured fluctuating light absorption by haemoglobin during pulsati...
Article
This study aims to provide evidence of the importance of radial peripapillary capillaries (RPCs) by quantitative study of the relationship between the RPCs and retinal nerve fibre layer (RNFL) in normal human donor eyes. The retinal microvasculature in eleven normal human donor eyes was perfused, fixed and labelled after cannulation of the central...
Article
Full-text available
Purpose: To determine whether morbidity and mortality in patients with cardiovascular comorbidities, but no known ocular disease, is related to demonstrable quantitative changes in the retinal microvasculature. Methods: 11 eyes from 8 donors with cardiovascular comorbidities as a diseased group were compared with 16 eyes from 14 donors free from va...
Article
Axonal cytoskeleton proteins are intrinsically related to retinal ganglion cell (RGC) health and disease. This study quantifies and documents the sectoral distribution of axonal cytoskeleton proteins in the different laminar compartments of the normal human optic nerve head (ONH).Nine human eyes were used (mean age of 46.9 ± 3.7 years). Coronal sec...
Article
Purpose: We have previously reported significant phenotype heterogeneity in the vortex vein system. This study is to quantify the age-related change of such endothelial phenotype heterogeneity. Method: The inferior temporal vortex vein system of 10 eyes from 7 young donors (30±4.1 years) and 9 eyes from 6 aged (72±4.7 years) donors were dissecte...
Article
This review is about vascular endothelial phenotype heterogeneity in the retinal and choroidal circulations. It is becoming increasingly clear that the functional and structural heterogeneity is present in the retinal and choroidal circulations. Differential responses of the vessels to vasoactive substances have been shown with intraluminal and ext...
Article
The endocannabinoid system plays a role in regulation of vasoactivity in the peripheral vasculature; however, little is known about its role in regulation of the CNS microvasculature. This study investigated the pharmacology of cannabinoids and cannabimimetic lipids in the retinal microvasculature, a CNS vascular bed that is autoregulated. Vessel d...
Article
Retinal ganglion cell (RGC) axonal structure and function in the optic nerve head (ONH) is predominantly supported by astrocytes and capillaries. There is good experimental evidence to demonstrate that RGC axons are perturbed in a non-uniform manner following ONH injury and it is likely that the pattern of RGC axonal modification bears some correla...
Article
Retinal ganglion cells (RGCs) are specialized projection neurons that relay an immense amount of visual information from the retina to the brain. RGC signal inputs are collected by dendrites and output is distributed from the cell body via very thin (0.5-1 μm) and long (∼50 mm) axons. The RGC cell body is larger than other retinal neurons, but is s...
Article
The vortex vein system is the drainage pathway for the choroidal circulation and serves an important function in the effective drainage of the exceptionally high blood flow from the choroidal circulation. As there are only 4-6 vortex veins, a large volume of blood must be drained from many choroidal veins into each individual vortex vein. The vorte...
Article
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To determine if patients with cardiovascular comorbidities but no clinically detectable retinal disease demonstrate quantitative alterations to perifoveal capillary networks. Methods: Comparisons were made between 10 eyes from patients with vascular comorbidities and 17 control eyes. All eyes were absent of clinically evident ocular disease. Micro-...
Article
Purpose: The aim of this study was to investigate whether region-dependent endothelial heterogeneity is present within the porcine vortex vein system. Methods: The superior temporal vortex vein in young adult pig eyes were dissected out and cannulated. The intact vortex vein system down to the choroidal veins was then perfused with labels for f-...
Article
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Purpose: To determine the ability of an intravitreal injection of tenecteplase (TNK) to penetrate an intraretinal venous thrombus and its effectiveness in thrombolysis in a porcine model of branch retinal vein occlusion (BRVO). Methods: Six pigs (group 1) were anesthetized, and a BRVO was induced photothrombotically in the left eye; immediately...
Article
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To evaluate the laser power required to rupture both the retinal vein and Bruch's membrane in a porcine model using a new laser system for treatment of retinal vein occlusion. The retina was treated in areas with and without an overlying vein. Sections through the laser sites were stained for light and transmission electron microscopy. The percenta...
Article
Vascular comorbidities are inherently linked to the pathogenesis of central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO). However, the endothelial-mediated pathogenic mechanisms that precede, and therefore modulate, luminal occlusion have not been clarified. The aim of this study was to delineate the pattern of endothel...