Jano van Hemert

Amazon · Customer Engagement

Workflow technologies are emerging as the dominant ap- proach to coordinate groups of distributed services. However with a space filled with competing specifications, standards and frameworks from mul- tiple domains, choosing the right tool for the job is not always a straight- forward task. Researchers are often unaware of the range of technology...

In conclusion, in this small series we confirmed that a stereographic projection algorithm using axial length information can produce accurate measurements relative to an intraocular ground-truth standard. This information should be valuable when designing and conducting clinical trials research that require quantitative analysis of fundus images.

Purpose: To assess whether the presence of peripheral nonperfusion on ultrawide field (UWF) fluorescein angiography (FA) is associated with diabetic retinopathy (DR) severity and the presence of predominantly peripheral lesions (PPLs). Design: Single-site, cross-sectional, retrospective study. Participants: Sixty-eight eyes of 37 diabetic subj...

Purpose: To establish the extent of the peripheral retinal vasculature in normal eyes using ultra-widefield (UWF) fluorescein angiography. Design: Prospective, observational study. Participants: Fifty-nine eyes of 31 normal subjects, stratified by age, with no evidence of ocular disease in either eye by history and ophthalmoscopic examination....

Our purpose was to investigate changes to the retina in multiple sclerosis (MS) using established and novel modes of retinal image acquisition and analysis. 72 participants with MS and 80 healthy volunteers underwent retinal scanning with optical coherence tomography (OCT) and ultra-widefield (UWF) scanning laser ophthalmoscopy (SLO), over a two-ye...

Diabetic retinopathy (DR) is characterized by microvascular changes including ischemia. Degradation and metabolic changes of various retinal cells occur during ischemia. Ischemic region containing more cells will lead to greater metabolic impairment. We analyzed the non-perfusion region (NPR) by integrating histologic mapping with ultra-widefield f...

Purpose This study aims to evaluate choroidal vascular alterations in patients with central serous chorioretinopathy (CSC) using ultra-widefield (UWF) indocyanine green angiography (ICGA). Methods This was a retrospective case–control study conducted at a single tertiary eye center. In total, 36 eyes in patients with either unilateral (24 patients...

Purpose: To compute retinal vascular bed area (RVBA) in mm2 on distortion corrected ultra-wide field (UWF) fluorescein angiography (FA) images in eyes with retinal vein occlusion (RVO). Methods: Prospective, observational study. The peripheral distortion of baseline UWF FA (Optos 200Tx) images of 30 patients with RVO from the WAVE study (NCT0171...

Purpose : Diabetic eyes with predominantly peripheral lesions (PPL) have been suggested to be at higher risk for progression to proliferative diabetic retinopathy (PDR). Retinal nonperfusion is known to increase with increasing severity of diabetic retinopathy. We sought to evaluate the relationship between macula vessel density metrics on optical...

Diabetic retinopathy (DR) is characterized by microvascular changes including ischemia. Degradation and metabolic changes of various retinal cells occur during ischemia. Ischemic region containing more cells will lead to greater metabolic impairment. We analyzed the non-perfusion region (NPR) by integrating histologic mapping with ultra-widefield f...

Purpose: To determine the relationship between baseline retinal non-perfusion area (NPA) and retinal vascular bed area (RVBA) on ultra-wide field fluorescein angiography (UWF FA) and long-term response to intravitreal ranibizumab therapy in diabetic macular oedema (DMO). Methods: A post-hoc, 2-year observational case series. Baseline UWF FA imag...

Purpose: To quantify changes of the retinal vascular bed area (RVBA) in mm2 on stereographically projected ultra-wide field (UWF) fluorescein angiography (FA) images by in eyes with proliferative diabetic retinopathy (PDR) following anti-vascular endothelial growth factor (VEGF) injection. Methods: Prospective, observational study. The early-pha...

Aims To quantify retinal vascular bed area (RVBA) in square millimetres on stereographically projected ultra-wide field (UWF) fluorescein angiography (FA) in eyes with diabetic retinopathy (DR). Methods A prospective, observational study. Baseline Optos 200Tx UWF FA images of 80 eyes with DR from the DAVE ( NCT01552408 ) and RECOVERY ( NCT02863354...

Background Ultra-widefiled (UWF) retinal images include significant distortion when they are projected onto a two-dimensional surface for viewing. Therefore, many clinical studies that require quantitative analysis of fundus images have used stereographic projection algorithm, three-dimensional fundus image was mapped to a two-dimensional stereogra...

We aimed to investigate the relationship between non-perfusion on ultra-widefield angiography (UWF FA) and aqueous cytokine levels and central macular thickness (CMT) in eyes with branch retinal vein occlusion (BRVO). Thirty-five eyes with treatment-naïve BRVO were included. Non-perfusion area (NPA) for partial and complete ischemia was manually se...

Purpose To investigate the correlation between macular microvascular alterations on optical coherence tomography angiography (OCTA) and retinal ischemia on ultra-widefield fluorescein angiography (UWF FA) in eyes with branch retinal vein occlusion (BRVO). Design Cross-sectional study Methods This prospective study was performed from September 201...

Polypoidal choroidal vasculopathy (PCV) is a common choroidal vascular disease particularly in Asians. However, the underlying pathogenesis of PCV is still yet to be fully elucidated, and the correlation between choroidal vasculature and treatment response of PCV are poorly understood. Accordingly, we sought to find clues to understand the pathogen...

Background: Ultra-widefiled (UWF) retinal images include significant distortion when they are projected onto a two-dimensional surface for viewing. Therefore, many clinical studies that require quantitative analysis of fundus images have used stereographic projection algorithm, three-dimensional fundus image was mapped to a two-dimensional stereogr...

Purpose: To evaluate the association of retinal nonperfusion and diabetic retinopathy (DR) severity with location of vascular caliber measurement using ultrawide field (UWF) imaging. Design: Retrospective image review SUBJECTS: Adult subjects with diabetes mellitus. Methods: All images from subjects with same day UWF fluorescein angiography (F...

Aim To analyse the peripheral extent of choroidal circulation using ultra-widefield (UWF) indocyanine green angiography (ICGA) in healthy eyes. Methods UWF ICGA images of 55 eyes of 36 healthy subjects were captured using the Optos California (Optos, Dunfermline, United Kingdom) in this prospective observational study. Images were analysed to loca...

We propose a convolutional neural network for localising the centres of the optic disc (OD) and fovea in ultra-wide field of view scanning laser ophthalmoscope (UWFoV-SLO) images of the retina. Images captured in both reflectance and autofluorescence (AF) modes, and central pole and eyesteered gazes, were used. The method achieved an OD localisatio...

Purpose To analyze the distribution of diabetic retinopathy (DR) lesions in an Indian population using ultra-wide field (UWF) fundus imaging. Methods Seven hundred fifteen subjects (1406 eyes) with diabetic retinopathy in India were enrolled in this multicenter, prospective, observational study using UWF pseudocolor imaging with Optos Daytona Plus...

We propose a convolutional neural network for localising the centres of the optic disc (OD) and fovea in ultra-wide field of view scanning laser ophthalmoscope (UWFoV-SLO) images of the retina. Images captured in both reflectance and autofluorescence (AF) modes, and central pole and eyesteered gazes, were used. The method achieved an OD localisatio...

Objective Changes to the retinal vasculature are known to be associated with hypertension independently of traditional risk factors. We investigated whether measurements of retinal vascular calibre from ultra-widefield fundus imaging were associated with hypertensive status. Methods We retrospectively collected and semiautomatically measured ultra...

Purpose: To study the number and distribution of vortex ampullae in healthy eyes using ultra-wide field (UWF) indocyanine green angiography (ICGA). Design: Prospective, observational study. Participants: Thirty-six eyes of 36 healthy participants with no evidence of ocular or systemic disease. Methods: The UWF ICGA images (central and periph...

Purpose: To correlate fractal dimension (FD) of the retinal vasculature with the extent of retinal nonperfusion area in diabetic retinopathy (DR) on ultrawide-field fluorescein angiography (FA). Design: Cross-sectional study. Methods: Baseline Optos 200Tx ultrawide-field FA images of 80 eyes with DR from the DAVE (NCT01552408) and RECOVERY (NC...

Purpose: To quantify retinal nonperfusion area and retinal vascular bed area (RVBA) in mm on ultra-widefield fluorescein angiography in eyes with diabetic macular edema (DME) and explore their relationship with the severity of DME. Methods: Prospective, observational case series. Baseline ultra-widefield fluorescein angiography images of 40 eyes...

Purpose: To explore the distribution of nonperfusion area (NPA) on ultrawide-field fluorescein angiography (UWF FA) in proliferative diabetic retinopathy (PDR) and its relationship with the presence of neovascularization of the optic disc (NVD) and distribution of neovascularization elsewhere (NVE). Design: Prospective, observational case series...

Purpose: To classify retinal nonperfusion regions (NPRs) in patients with diabetic macular edema (DME) and assess the relationship with severity of DME. Design: Prospective, observational case series. Methods: Forty eyes of 29 patients with treatment-naïve center-involved macular edema secondary to diabetes mellitus were included (The DAVE stu...

Background: To evaluate changes in image sharpness across ultrawide field (UWF) images and the effect of phase-plate adjustment on image contrast and extent of visible retinal area (VRA). Methods: This was a single site evaluation of 200° UWF images acquired with phase-plate adjustment (California, Optos, plc) and without (200TX, Optos, plc). Im...

Fundus images from the left eyes of 440 subjects aged 50-59 years enrolled in the Northern Ireland Cohort of Longitudinal Ageing were analyzed. Subjects were categorized as normotensive or hypertensive, according to thresholds on systolic/diastolic blood pressure measurement (140/90 mm Hg) averaged over two sitting measurements in a clinical settin...

Purpose: The purpose of this study was to compare the use of central and montaged ultra-wide-field fluorescein angiography (UWFFA) images for calculating the area of nonperfusion (NP) and ischemic index (ISI) in patients with retinal vein occlusion (RVO) and macular edema (ME) and to correlate these measurements with best-corrected visual acuity (...

Aim To evaluate changes in the ischaemic index (ISI) after targeted retinal photocoagulation (TRP) and to investigate the correlation between these changes and macular oedema (ME). Method Twenty-four eyes of 24 patients with retinal vein occlusion (RVO) with recurrent ME were included. Ultra-widefield fluorescein angiography (UWFFA; Optos 200Tx) w...

Importance Predominantly peripheral disease in eyes with nonproliferative diabetic retinopathy (DR) is suggested as a potential strong risk factor for progression to proliferative disease. However, the reliability and optimal method for the assessment of lesion distribution are still uncertain. Objective To compare agreement between subjective ass...

Purpose: To characterize and quantify the total retinal vascular bed area (RVBA) and vascular density (VD) in normal eyes using stereographically-corrected ultra-wide (UWF) fluorescein angiography (FA). Design: Cross-sectional study Methods: Fifty-nine eyes of 31 normal subjects with no evidence of ocular disease underwent FA using the Optos 200Tx....

This paper proposes a novel Adaptive Region-based Edge Smoothing Model (ARESM) for automatic boundary detection of optic disc and cup to aid automatic glaucoma diagnosis. The novelty of our approach consists of two aspects: 1) automatic detection of initial optimum object boundary based on a Region Classification Model (RCM) in a pixel-level multid...

We demonstrate a multimode detection system in a scanning laser ophthalmoscope (SLO) that enables simultaneous operation in confocal, indirect, and direct modes to permit an agile trade between image contrast and optical sensitivity across the retinal field of view to optimize the overall imaging performance, enabling increased contrast in very wid...

The classification of blood vessels into arterioles and venules is a fundamental step in the automatic investigation of retinal biomarkers for systemic diseases. In this paper we present a novel technique for vessel classification on ultra-wide-fieldof- view images of the retinal fundus acquired with a scanning laser ophthalmoscope. To our best kno...

Purpose To evaluate vortex vein engorgement and choroidal vascular hyperpermeability in patients with central serous chorioretinopathy (CSC) using ultra‐widefield indocyanine green angiography (UWF ICGA). Methods Twenty two patients with unilateral (19 patients) or bilateral (3 patients) CSC were consecutively included and imaged by UWF autofluore...

Purpose To explore the distribution of nonperfusion area (NPA) in eyes with diabetic macular edema (DME) and its relationship with the severity of DME. Design Prospective, observational case series. Methods Forty eyes of 29 patients with treatment-naïve DME who participated in the DAVE study (NCT01552408) were included. Ultra-wide field fluoresce...

Objective: To evaluate detection of hemorrhage and/or microaneurysm (H/Ma) using ultrawide field (UWF) retinal imaging as compared with standard Early Treatment Diabetic Retinopathy Study (ETDRS) 7-field photographs (ETDRS photos). Design: Single-site comparative study of UWF images and ETDRS photos. Participants: One hundred twenty-six eyes o...

Modern scientific collaborations have opened up the opportunity to solve complex problems that require both multidisciplinary expertise and large-scale computational experiments. These experiments typically consist of a sequence of processing steps that need to be executed on selected computing platforms. Execution poses a challenge, however, due t...

Glaucoma is one of the leading causes of blindness worldwide. There is no cure for glaucoma but detection at its earliest stage and subsequent treatment can aid patients to prevent blindness. Currently, optic disc and retinal imaging facilitates glaucoma detection but this method requires manual post-imaging modifications that are time-consuming an...

Glaucoma is one of the leading cause of blindness but the detection at its earliest stage and subsequent treatment can aid patients to preserve blindness. The existing work has been focusing on global features such as texture, grayscale and wavelet energy of the Optic Nerve Head (ONH) and its surrounding to differentiate between normal and glaucoma...

To determine the calculated, anatomically correct, area of retinal non-perfusion and total area of visible retina on ultra-widefield fluorescein angiography (UWF FA) in retinal vein occlusion (RVO) and to compare the corrected measures of non-perfusion with the ischaemic index. Uncorrected UWF FA images from 32 patients with RVO were graded manuall...

Optical coherence tomography (OCT) and reflectance imaging are used in clinical practice to measure the thickness and transverse dimensions of retinal features. The recent trend towards increasing the field of view (FOV) of these devices has led to an increasing significance of the optical aberrations of both the human eye and the device. We report...

In this chapter we will focus on the combination of evolutionary computation (EC ) techniques and constraint satisfaction problems (CSP s). Constraint programming (CP ) is another approach to deal with constraint satisfaction problems. In fact, it is an important prelude to the work covered here as it advocates itself as an alternative approach to...

Features of the retinal vasculature, such as vessel widths, are considered biomarkers for systemic disease. The aim of this work is to present a supervised approach to vessel segmentation in ultra-wide field of view scanning laser ophthalmoscope (UWFoV SLO) images and to evaluate its performance in terms of segmentation and vessel width estimation...

Multiple Sequence Alignment (MSA) constitutes an extremely power-ful tool for important biological applications such as phylogenetic anal-ysis, identification of conserved motifs and domains and structure pre-diction. In spite of the improvement in speed and accuracy introduced by MSA programs, the computational requirements for large-scale align-m...

An 'Intellectual Ramp' enables researchers to move incrementally from their current practice into the adoption of new methods. An investigation of Ramps is an important step towards "crossing the chasm" so that researchers can benefit from new tools, technologies and approaches. This paper will define and explain the concept of Ramps, discuss requi...

Distinguishing true retinal area from artefacts in SLO images is a challenging task, which is the first important step towards computer-aided disease diagnosis. In this paper, we have developed a new method based on superpixel feature analysis and classification approaches for determination of retinal area scanned by Scanning Laser Ophthalmoscope(S...

Scanning Laser Ophthalmoscopes (SLOs) can be used for early detection of retinal diseases. With the advent of latest screening technology, the advantage of using SLO is its wide Field of View (FOV), which can image a large part of the retina for better diagnosis of the retinal diseases. On the other hand, during the imaging process, artefacts such...

Background and objective: Accurate quantification of retinal surface area from ultra-widefield (UWF) images is challenging due to warping produced when the retina is projected onto a two-dimensional plane for analysis. By accounting for this, the authors sought to precisely montage and accurately quantify retinal surface area in square millimeters...

We report the design, manufacture and assessment of a phantom eye that can be used to measure the performance and accuracy of ophthalmic-OCT devices. We base our design on a wide-field schematic eye, R. Navarro, J. Opt. Soc. Am. A 2 (1985), to allow the assessment of device performance relative to +/- 70° external field of view. We have fabricated...

Retinal capillary abnormalities include small, leaky, severely tortuous blood vessels that are associated with a variety of retinal pathologies. We present a prototype image-processing system for detecting abnormal retinal capillary regions in ultra-widefield-of-view (UWFOV) fluorescein angiography exams of the human retina. The algorithm takes as...

This book presents the most up–to–date opportunities and challenges emerging in knowledge discovery, helping readers develop the technical skills to design and develop data–intensive methods and processes. Offering an introduction to the current R and D efforts worldwide, the book includes examples and case studies with strategies for addressing a...

This chapter aims at providing data analysis experts with an overview of the most common strategies in knowledge discovery, highlighting those steps or blocks of steps that are most likely to appear in common problem solving in conventional and data-intensive contexts, as well as giving examples that can be replicated in a range of problems in diff...

This chapter describes the application of data-intensive methods to the automatic identification and annotation of gene expression patterns in the mouse embryo. The first section of the chapter introduces ideas behind modern computational and systems biology, how the explosion of data in the postgenomic world has led to new possibilities and even g...

This chapter presents a set of scenarios that introduce different types of data analysis problems of increasing complexity, which could be handled by a team of data analysts in a telecommunications company, Telco Inc. It starts with a rather conventional scenario where a customer churn prediction model is built from the company's own data sources....

In this paper, we propose an algorithm based on active shape model for the extraction of Optic Disc boundary. The determination of Optic Disc boundary is fundamental to the automation of retinal eye disease diagnosis because the Op-tic Disc Center is typically used as a reference point to lo-cate other retinal structures, and any structural change...

Manual annotation of enzymatic functions cannot keep up with automatic genome sequencing. In this work we explore the capacity of InterPro sequence signatures to automatically predict enzymatic function. We present EnzML, a multi-label classification method that can efficiently account also for proteins with multiple enzymatic functions: 50,000 in...