Georg Michelson

Georg Michelson
Universitätsklinikum Erlangen · Department of Ophthalmology

Prof. Dr. med.

About

276
Publications
19,732
Reads
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5,261
Citations
Additional affiliations
June 1983 - present
Universitätsklinikum Erlangen
Position
  • Professor Of Ophthalmology
January 1983 - present
Friedrich-Alexander-University of Erlangen-Nürnberg
Position
  • Professor (Associate) of Ophthalmology

Publications

Publications (276)
Article
Full-text available
The visual depth perception is composed of monocular and binocular depth cues. Studies show that in absence of binocular depth cues the performance of visuomotor tasks like pointing to or grasping objects is limited. Thus, binocular depth cues are of great importance for motor control required in everyday life. However, binocular depth cues like re...
Article
Background: Optimal visual abilities including stereo acuity seem to be an important issue in sports. There is increasing evidence that stereo acuity can be sustainably improved by digital vision training even for people with good stereo acuity. Study design and test methods: In this study 31 male and female tennis players (professionals, young...
Conference Paper
Strabismus is a visual disorder characterized by eye misalignment. The extent of ocular misalignment is denoted as the deviation angle. With the advent of Virtual Reality (VR) Head-Mounted-Displays (HMD) and eye tracking technology, new possibilities measuring strabismus arise. Major research addresses the novel field of VR strabismus assessment by...
Article
Full-text available
Background: We showed that seniors can improve their stereoscopic ability (stereoacuity) and corresponding reaction time with repetitive training and, furthermore, that these improvements through training are still present even after a longer period of time without training. Methods: Eleven seniors (average age: 85.90 years) trained twice a week...
Article
Full-text available
PurposeThe study aimed to evaluate stereopsis as a surrogate marker for post-concussion oculomotor function to develop an objective test that can reliably and quickly detect mild traumatic brain injuries (TBI).Methods The cohort of this prospective clinical study included 30 healthy subjects (mean age 25 ± 2 years) and 30 TBI patients (43 ± 22 year...
Article
Full-text available
Spectral-domain optical coherence tomography (SD-OCT) represents a reliable tool for retinal layer volume and thickness measurement. The aim of this study was to evaluate retinal changes indicating neurodegenerative processes in patients with end-stage renal disease (ESRD) compared to healthy controls. This was a cross-sectional, single-center stud...
Article
Full-text available
Purpose To avoid significant loss of vision in employees, the working population could be examined with ophthalmic methods as OCT and IOP measurement for detection of serious eye diseases. The value of “virtual eye clinics” in occupational preventive medicine has been previously shown. We used a telemedical approach to gather epidemiological inform...
Article
Objective: Initiation of antihypertensive drug treatment in low-risk individuals with grade 1 hypertension is under debate. The aim of this study was to examine the impact of mildly elevated blood pressure (BP) on early neurodegenerative processes independent of ageing. Methods: Sixty-two individuals were included in this study: 25 young (aged <...
Article
Zusammenfassung Bei Glaukomen ist die Darstellung der Sehbahn mittels Diffusionsbildgebung und metabolischer MRT möglich; es findet sich mit zunehmendem Alter eine Atrophie der Sehstrahlung, welche das Ausmaß der physiologischen Hirnvolumenminderung deutlich übersteigt. Bei den unterschiedlichen Glaukomsubtypen erlaubt die qualitative Auswertung de...
Article
Full-text available
Background There is evidence that glaucoma is a neurodegenerative disease involving the whole visual pathway. We prospectively examined potential benefits of volumetry of the lateral geniculate nucleus (LGN) and diffusion tensor imaging (DTI) using a new 7T scanner. Methods 20 patients with normal tension glaucoma and 16 control individuals were e...
Article
Objectives: To measure the density of retinal vessels from digitized fundus photographs in patients with recent stroke and age-matched controls. To investigate whether the parameter retinal vascular density (RVD) served as a quantitative marker for cerebrovascular events. Methods: Digitized fundus photographs of n = 158 subjects with stroke or t...
Article
Full-text available
Retinal image quality assessment (RIQA) is the first step performed in retinal image processing systems necessary to assure that the processed images are suitable for analysis and medical diagnosis. RIQA algorithms created for controlled environments can result in degraded performance for cross-dataset experiments in which the train and test images...
Chapter
Die Verbesserung der medizinischen Versorgung benötigt u. a. eine kontinuierliche augenmedizinische Fortbildung und eine Möglichkeit der sofortigen und unmittelbaren Unterstützung des Augenarztes bei der Arbeit am Patienten. Ein wichtiger Baustein für eine Diagnose-Unterstützung ist eine webbasierte Referenzbilderdatenbank mit allen augenärztlichen...
Article
Purpose: Retinal microcirculation represents an easily accessible, non-invasive, in-vivo possibility to assess early microvascular changes. In addition to the assessment of functional (e.g. retinal capillary flow, RCF) and retinal arteriolar structural parameters (e.g. wall-to-lumen-ratio, WLR) we now suggest a new parameter reflecting the resistan...
Chapter
Durch regional unterschiedlich auftretende Effekte bei der ärztlichen Niederlassung sinkt die augenärztliche Versorgung auf dem „flachen Land“. Es wird geschätzt, dass es bis zum Jahr 2020 durch Verdünnung der augenärztlichen Versorgung zu einer Versorgungsabnahme von ca. 11 % und es zu einer Zunahme von augenärztlich versorgungsbedürftigen Persone...
Article
Retinal image quality assessment (RIQA) is essential to assure that the images investigated by ophthalmologists or automatic systems are suitable for reliable medical diagnosis. Measure-based RIQA techniques have several advantages over the more commonly used binary classification-based RIQA methods. Numeric quality measures can aid ophthalmologist...
Article
Background: Current studies revealed the importance of perceptual training for the treatment of amblyopia. To improve stereo vision on a higher level, visual tasks have to be completed within a limited time window like in repetitive visual function tests. "Processing time" as the reaction time in which the absence or presence of depth was identifi...
Article
In Deutschland sind mehr als 1 Mio. Einwohner an Glaukom erkrankt, in über 100.000 Fällen droht die Erblindung, auch weil die Diagnose oft nicht oder zu spät gestellt wird. Diese erfolgt in der Regel – wie auch die Therapiekontrolle – „nur“ durch Untersuchung der Netzhaut und nicht der gesamten Sehbahn. Dabei ist das Auge aber nur die „Spitze des E...
Article
Full-text available
The aim of the study is to telemedically assess the prevalence of simple optic nerve atrophy and retinal arteriolar anomalies in subjects who have had a minor stroke or TIA within 14 days, and to compare these results with an age-matched control group. By using a mobile examination unit, retinal photographs were taken with a 45° non-mydriatic colou...
Article
Full-text available
Retinal image quality assessment (RIQA) is an essential step in automated screening systems to avoid misdiagnosis caused by processing poor quality retinal images. A no-reference transform-based RIQA algorithm is introduced that assesses images based on five clarity and content quality issues: sharpness, illumination, homogeneity, field definition,...
Conference Paper
Todays organizations are socio-technical entities, and interactions have significant impact on their success. Around 50% of the work in the US is knowledge work, and other countries show a similar tendency. Compliance monitoring of course can only cover processes and tasks that are modeled or documented somehow. Therefore, today it faces the proble...
Article
Background: Eutrophic and hypertrophic remodeling are major vascular hallmarks for hypertension and diabetes associated microvascular end-organ damage in peripheral arterioles. The aim of this study is to compare retinal arterioles of diabetic, hypertensive and healthy individuals. Methods: Retinal parameters were assessed in 99 patients with ty...
Article
Background: Recent studies suggest vascular benefits of dipeptidylpeptidase IV (DPP-IV) inhibition in patients with diabetes mellitus. Only little is known about potential vascular effects of DPP-IV inhibitors in nondiabetic individuals. The aim of this study was to investigate the effect of DPP-IV inhibition in a nondiabetic hypertensive populati...
Chapter
Full-text available
Glaucoma is one of the major causes for blindness with a high rate of unreported cases. To reduce this number, screening programs are performed. However, these are characterized by a high workload for manual and cost-intensive assessment. Computer-aided diagnostics (CAD) to perform an automated pre-exclusion of normals might help to improve program...
Article
Objective: To examine the prevalence of optic nerve atrophy, retinal microvascular narrowing and arteriovenous nicking in a normotensive, nondiabetic, “healthy” population using telemedical techniques. Methods: By the Tele-ophthalmic Consultation Service Talkingeyes®, N = 1,662 normotensive, nondiabetic subjects aged 41–89 years without any systemi...
Article
Full-text available
Tele-ophthalmology requires low-cost devices that are easy to use and robust. A new imaging method was invented and applied, which is capable of acquiring wide-field color fundus images with 68×18° field of view at pupil sizes of only 2 mm. As a consequence there was no need for pupil dilatation or darkened examination rooms. Furthermore, many imag...
Article
Objective: To prevent vision-threatening eye diseases in nonindustrialized countries, a continuous medical education is necessary. Professionally interested parties of these countries often lack access to good illustrative material of normal and rare diseases. Purpose and Main Outcome Measure: Quantification of worldwide acceptance of the social me...
Conference Paper
Full-text available
Retinal Image Quality Assessment (RIQA) is an essential preliminarily step in automatic retinal screening systems (ARSS) to avoid misdiagnosis of retinal disease. In this work, a no-reference wavelet based RIQA algorithm suitable for real-time ARSS is introduced. Retinal images are classified into good and bad quality images using two proposed metr...
Article
To measure the wall-to-lumen ratio (WLR) and the cross-sectional area of the vascular wall (WCSA) of retinal arterioles by an Adaptive Optics (AO) retinal camera. Forty-seven human subjects were examined and their medical history was explored. WLR and WCSA were measured on the basis of retinal arteriolar wall thickness (VW), lumen diameter (LD) and...
Article
Objective: Vascular remodeling in the retinal circulation represents an easily accessible, non-invasive, in-vivo possibility to assess early microvascular changes, especially as a model of brain microperfusion. In addition to the assessment of functional (e.g. retinal capillary flow, RCF) and retinal arterial structural parameters (e.g. wall-to-lum...
Article
High pulsatile pressure and flow in the arteries causes microvascular damage, and hence increased cardio-, and cerebrovascular complications. With advanced stages of hypertensive disease, an exaggerated pulsatile retinal capillary flow (RCF) has been shown, but data about interventional effect are missing. Fifty-one patients with true treatment-res...
Book
This book provides an up-to-date overview of the clinical applications, methods, and technologies of teleophthalmology within the field of preventive medicine. The ability of novel methods to detect the initial signs of systemic and neurodegenerative diseases on the basis of alterations in the retina is reviewed, and detailed attention is paid to e...
Article
Full-text available
Stereopsis is one of several visual depth cues. It has been evaluated for athletes of different types of sports in the past. However, most studies do not cover the full range of stereopsis performance. Therefore, we propose computer-supported stereopsis tests that provide an extended assessment and analysis of stereopsis performance including stere...
Article
Purpose: To evaluate the correlation between the extent of cerebral white matter lesions (WMLs) and the integrity of the visual pathway represented by fractional anisotropy (FA) in patients with primary open-angle glaucoma (POAG). Methods: This case-control study included a total of 61 German patients (39 POAG patients, 22 controls) matched for...
Conference Paper
Full-text available
This paper proposes a novel super-resolution framework to reconstruct high-resolution fundus images from multiple low-resolution video frames in retinal fundus imaging. Natural eye movements during an examination are used as a cue for super-resolution in a robust max-imum a-posteriori scheme. In order to compensate heterogeneous illu-mination on th...
Conference Paper
This paper proposes a novel super-resolution framework to reconstruct high-resolution fundus images from multiple low-resolution video frames in retinal fundus imaging. Natural eye movements during an examination are used as a cue for super-resolution in a robust maximum a-posteriori scheme. In order to compensate heterogeneous illumination on the...
Article
Mikroangiopathische Veränderungen der Retina korrelieren — unabhängig von traditionellen Risikofaktorenmit zur Erblindung führenden Augenerkrankungen und mit zerebround kardiovaskulären Risikofaktoren bzw. Erkrankungen wie dem metabolischen Syndrom, Alter, arteriellem Bluthochdruck, Schlaganfall und Myokardinfarkt. Die Untersuchung der Netzhaut erm...
Article
Objective: Increased pulsatile pressure induces as well as aggravates microvascular damage. Scanning laser Doppler flowmetry allows the noninvasive assessment of both retinal capillary flow (RCF) and arteriolar structural parameters of the retinal circulation. Moreover, pulsatile characteristics of the retinal arterioles can be assessed. Methods:...
Article
Full-text available
Background and Purpose Tract-based spatial statistics (TBSS) has been used to assess the integrity of the visual pathway in glaucoma patients. TBSS uses the subjects’ FA data to create a mean FA skeleton of white matter tracts before running voxel-wise cross-subject statistics. We compared four different approaches of registration of FA maps to cre...
Conference Paper
Full-text available
Fundus video cameras enable the acquisition of image sequences to analyze fast temporal changes on the human retina in a noninvasive manner. In this work, we propose a tracking-by-detection scheme for the optic disk to capture the human eye motion on-line during examination. Our approach exploits the elliptical shape of the optic disk. Therefore, w...
Article
One of the most common modalities to examine the eyebackground is the fundus image. These images are photographs taken through the pupil by a fundus camera. The evaluation of these images is usually carried out by ophthalmologists or experts during visual inspection. The aim of our work is to accelerate this process by a fullyautomatic screening. T...
Article
Full-text available
In patients with diabetes mellitus (DM), early retinal microvascular alterations can be observed even before the clinical diagnosis of diabetic retinopathy. This study aimed to investigate morphological and functional changes in retinal microvascular blood flow in type 1 diabetic patients with and without peripheral neuropathy (PNP) as compared to...
Article
This case report depicts the clinical course of a female patient with unilateral retinitis pigmentosa (RP), who presented first in 1984 at the age of 43 years. At the beginning, there were cells in the vitreous leading to the diagnosis of uveitis with vasculitis. Within 30 years, the complete clinical manifestation of RP developed with bone spicule...
Article
We describe a method we call "stripe field imaging" that is capable of capturing wide field color fundus videos and images of the human eye at pupil sizes of 2mm. This means that it can be used with a non-dilated pupil even with bright ambient light. We realized a mobile demonstrator to prove the method and we could acquire color fundus videos of s...
Article
To test visual function after repetitive tests of visual acuity (VA) and contrast sensitivity (CS). Ten young female subjects performed repetitive tests of visual functions over ten sessions within 5 weeks. Per week they performed two 30 min sessions of repetitive tests of central VA, CS and vernier acuity (VT) using Michael Bach's Freiburg Vision...
Article
Purpose: In the literature, different graphic illustrations are available, which depict different parts of the visual pathway in relation to visual field sectors, to retinal sectors, the layers of the lateral geniculate nucleus (LGN), or sections of the primary visual cortex (V1). However, a complete overview is missing, which may be useful for a...
Article
We present a novel approach that simulates human vision including visual defects such as glaucoma by temporal composition of human vision in real-time on the GPU. Therefore, we determine eye focus points every time step and adapt the lens accommodation of our virtual eye model accordingly. The focal distance is then used to determine bluriness of o...
Article
Purpose: To present a system for performance evaluation of stereopsis for beach volleyball players. Methods: Our dynamic stimulus consists of four equally rendered spheres with volleyball textures each rotating around its x-axis presented on a polarized 32'' 3D-TV (1920x1080p) at a distance of 5 m. All spheres have the same crossed disparity of 15...
Conference Paper
Full-text available
3D displays enable immersive visual impressions but the impact on the human perception still is not fully understood. Viewing conditions like the convergence-accommodation (C-A) conflict have an unnatural influence on the visual system and might even lead to visual discomfort. As visual perception is individual we assumed the impact of simulated 3D...
Article
Most of the existing methods for diagnosing glaucoma analyze the eye with a main focus on the retina, despite the transsynaptic nature of the fiber degeneration caused by glaucoma. Thus, they ignore a significant part of the visual system represented by the visual pathway in the brain. The advances in neuroimaging, especially diffusion tensor imagi...
Conference Paper
Fundus imaging is one of the most frequently used modalities for screening, diagnosis of eye diseases and some vascular abnormalities. Due to its wide availability, automatic evaluation of fundus images offers great potential benefits to current clinical practice. The basis of many automatic evaluations or diagnosis is the segmentation of the eye b...
Conference Paper
Full-text available
Fundus imaging is the most commonly used modality to collect information about the human eye background. Objective and quantitative assessment of quality for the acquired images is essential for manual, computer-aided and fully automatic diagnosis. In this paper, we present a no-reference quality metric to quantify image noise and blur and its appl...
Article
Full-text available
Introduction: Scanning laser Doppler flowmetry (SLDF) plays an important role in the study of arterial hypertension, diabetes and stroke. The technology enables non-invasive measurement of the retinal capillary perfusion (RCF), retinal haemodynamics and arteriolar morphology in human. The values can be measured in mydriasis or in non-mydriatic eye...
Article
Full-text available
Numerous rheological and microvascular alterations characterize the vascular pathology in patients with type 2 diabetes mellitus (T2DM). This study investigated effects of vildagliptin in comparison to glimepiride on retinal microvascular blood flow and erythrocyte deformability in T2DM. Fourty-four patients with T2DM on metformin monotherapy were...
Article
Pulse pressure has been recognized as a risk factor for stroke. Moreover, it was shown that central pulse pressure relates more strongly to vascular disease and outcome than (peripheral) brachial pulse pressure. Because vascular remodeling in the retinal circulation mirrors the 1 in the cerebral circulation and represents an easy, noninvasive possi...
Article
Full-text available
Background Patients with recent stroke or TIA are at high risk for new vascular events. Several evidence based strategies in secondary prevention of stroke are available but frequently underused. Support programs with multifactorial risk factor modifications after stroke or TIA have not been investigated in large-scale prospective controlled trials...
Article
Objective: Haemoglobin is a potential nitric oxide (NO) scavenger. Haemoglobin is associated with blood viscosity and the red blood cell free layer width of microvessels that impact on shear stress in the microcirculation. We hypothesized that haemoglobin modulates retinal vascular function. Methods: In 139 nondiabetic male patients with haemogl...
Article
Full-text available
One of the most common modalities to examine the human eye is the eye-fundus photograph. The evaluation of fundus photographs is carried out by medical experts during time-consuming visual inspection. Our aim is to accelerate this process using computer aided diagnosis. As a first step, it is necessary to segment structures in the images for tissue...
Article
Purpose In glaucomatous optic nerve atrophy (glOA) damage of retinal ganglion cells may continue to the linked optic radiations (OR). This study investigated differences between glOA and non-glOA in relation to impairment of the optic radiations using DTI-MRI. Methods We examined 42 patients with healthy optic nerve head and no ophthalmological sig...
Article
Objective: We aimed to analyse whether there is an early association of retinal arteriolar structure and renal function in patients with essential hypertension and yet normal renal function. Methods: In 144 patients with essential hypertension (and without renal disease (eGFR-CKD EPI >60 ml/min/1.73m2 (range 60.2-112 ml/min/1.73m2)) we analyzed str...
Article
We hypothesized that the increase of retinal capillary blood flow (RCF) to flicker light exposure is impaired in subjects with arterial hypertension. In 146 nondiabetic untreated male subjects with (n=50) or without (n=96) arterial hypertension, RCF was measured before and after flicker light exposure noninvasively and in vivo using scanning laser...
Article
Full-text available
Purpose of this study was to evaluate with diffusion-tensor imaging (DTI) changes of radial diffusivity (RD) and fractional anisotropy (FA) in the optic nerve (ON) and optic radiation (OR) in glaucoma and to determine whether changes in RD and FA correlate with disease severity. Therefore, glaucoma patients and controls were examined using 3T. Regi...