OCT and IOP findings in a healthy worker cohort: results from a teleophthalmic study in occupational medicine.

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 information about prevalence of eye diseases such as glaucoma, ocular hypertension, hypertensive retinopathy, diabetic retinopathy, epiretinal membrane, AMD, adult vitelliform maculopathy, cystoid maculopathy, choroidal nevi, and macular drusen. METHODS: The study included 931 people ranging from age 39 to 65 years. Using a telemedical approach, all medical examinations and the ophthalmic examination were performed by a technician using an optical coherence tomography (SD-OCT) and a pulse air tonometer. The data were saved in the web-based patient chart MedStage® of the Talkingeyes® Collaboration Network. RESULTS: We found a high prevalence of eye diseases in a group representative for the working-age population by telemedical examination. 13.47% of the workers examined showed ocular findings necessitating treatment or control by an ophthalmologist, including ocular hypertension (5.7%), hypertensive retinopathy with loss of temporal retinal nerve fiber thickness (2.3%), epiretinal membrane (1.07%), glaucoma (0.97%), age-related macular degeneration and adult vitelliform maculopathy (0.53%), and diabetic retinopathy (0.2%). Two of the examined persons presented ocular findings requiring urgent treatment to prevent serious vision loss. CONCLUSION: Using a telemedical approach, we collected epidemiological information about prevalence of eye diseases in the working-age population. Virtual eye clinics in occupational preventive medicine are a useful method to improve sight and reduce vision loss of workers by reducing travel time and inconvenience associated with an in-person appointment with an ophthalmologist.

[Diffusion tensor imaging of the visual pathway in glaucomatous optic nerve atrophy]. / Diffusionsbildgebung der Sehbahn bei glaukomatöser Optikusatrophie.

In Germany more than one million inhabitants suffer from glaucoma, more than 100,000 are threatened with blindness because glaucoma is often diagnosed too late or not at all. Diagnosis and monitoring is usually carried out "only" by examination of the retina and not the whole visual pathway. However, the eye is just "the tip of the iceberg" of the actual visual pathway, which extends through the brain to the visual cortex. The interdisciplinary holistic assessment of the whole visual pathway in glaucoma is of crucial importance because glaucoma is a complex neurodegenerative disease. Subtypes, such as normal tension glaucoma (NTG), seem to originate from primary damage to the intracranial visual pathway with secondary retrograde retinal degeneration. Recent studies including glaucoma patients and healthy controls could show that diffusion tensor imaging with calculation of diffusion coefficients, i.e. fractional anisotropy (FA), mean and radial diffusivity (MD and RD) as markers of axonal integrity, provide the potential to assess the intracranial visual pathway with a high correlation to established ophthalmological examinations. In particular, calculation of FA maps of the visual pathway and accompanying voxel-based approaches, can be integrated into clinical routine. Thus, detection of glaucoma-related intracranial alterations, even in early stages of the disease, as well as differentiation of different glaucoma subtypes, is made possible. Furthermore, the diagnosis of normal tension glaucoma seems to be possible much earlier with these new imaging techniques compared to established ophthalmological work-up. Moreover, holistic imaging provides new insights into the pathophysiology of this form of glaucoma. This review article gives an overview of these novel magnetic resonance imaging techniques for assessment of the visual pathway in glaucomatous optic nerve atrophy and reveals the potential of an interdisciplinary approach.

Robust vessel segmentation in fundus images.

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 differentiation. As the eye is the only organ, where the vasculature can be imaged in an in vivo and noninterventional way without using expensive scanners, the vessel tree is one of the most interesting and important structures to analyze. The quality and resolution of fundus images are rapidly increasing. Thus, segmentation methods need to be adapted to the new challenges of high resolutions. In this paper, we present a method to reduce calculation time, achieve high accuracy, and increase sensitivity compared to the original Frangi method. This method contains approaches to avoid potential problems like specular reflexes of thick vessels. The proposed method is evaluated using the STARE and DRIVE databases and we propose a new high resolution fundus database to compare it to the state-of-the-art algorithms. The results show an average accuracy above 94% and low computational needs. This outperforms state-of-the-art methods.

Addition of liraglutide in patients with Type 2 diabetes well controlled on metformin monotherapy improves several markers of vascular function.

AIMS: The aim of this study was to investigate the vascular effects of liraglutide in patients well controlled on metformin monotherapy. METHODS: Forty-four patients with Type 2 diabetes were included in the study. Main inclusion criteria were: pretreatment with metformin on a stable dosage, HbA(1c) < 53 mmol/mol (7.0%), age 30-65 years. Patients were randomized to receive additional liraglutide or to remain on metformin monotherapy. After 6 weeks (1.2 mg) and after 12 weeks (1.8 mg), venous blood was taken for the measurement of several laboratory markers characterizing vascular and endothelial function. In addition, retinal microvascular endothelial function and arterial stiffness were measured. RESULTS: HbA(1c) levels declined from 45 ± 4 mmol/mol (6.3 ± 0.4%; mean ± SD) to 40 ± 3 mmol/mol (5.8 ± 0.3%) during liraglutide treatment. Asymmetric dimethylarginin was reduced by liraglutide treatment from 0.39 ± 0.08 to 0.35 ± 0.06 µmol/l, E-selectin from 43.6 ± 15.4 to 40.8 ± 15.1 ng/ml, plasminogen activator inhibitor 1 from 861.6 ± 584.3 to 666.1 ± 499.4 ng/ml and intact proinsulin from 9.0 ± 7.2 to 7.0 ± 4.8 pmol/l at 12 weeks of treatment. The microvascular response to flicker light increased from 7.0 ± 15.1 to 15.4 ± 11.5% after 6 weeks and to 11.1 ± 9.9% after 12 weeks. No change could be observed for high-sensitivity C-reactive protein, monocyte chemotactic protein 1, vascular cell adhesion molecule or arterial stiffness parameters. CONCLUSIONS: In patients with Type 2 diabetes, well controlled with metformin monotherapy, addition of liraglutide improves several cardiovascular risk markers beyond glycaemic control.

[Integrity/demyelination of the optic radiation, morphology of the papilla, and contrast sensitivity in glaucoma patients]. / Integrität/Demyelinisierung der Radiatio optica, Morphologie der Papille und Kontrastsensitivität bei Glaukompatienten.

BACKGROUND: In primary open angle glaucoma (POAG) and its non-barotraumatic subgroup, normal tension glaucoma (NTG), the pathophysiological differences are not clear. A participation of the 4th neuron of the visual pathway (optic radiation) appears possible on the basis of related experimental studies. The goal of the present study was the evaluation of the optic radiation by diffusion tensor imaging (DTI), which is based on the magnetic resonance imaging. The diffusion and anisotropy parameters of the optic radiation as a marker of axonal integrity and demyelination/damage of glial cells, respectively, were used to investigate the relation between the morphology of the papilla (BLDF, linear discriminant function of Burk) and the contrast sensitivity (FDT, frequency doubling test). PATIENTS AND METHODS: In this prospective observational study 13 POAG patients, 13 NTG patients, and 7 control patients of the same mean age were included. For segmentation of the optic radiation a semi-automated algorithm was applied and the diffusion and anisotropy parameters were calculated. The importance of the covariates age, BLDF, and FDT for the DTI parameters was determined using partial correlation analysis. RESULTS: Analysis of the covariates partially showed a clear autocorrelation. The correlations between the DTI parameters and BLDF were significant in all groups after correction of the measurement values for the covariates. FDT correlated with DTI parameters in controls and POAG. The NTG group did not show this correlation due to a strong spreading of the FDT values. CONCLUSION: After statistical elimination of the autocorrelation of the covariates age, BLDF, and FDT the morphology of the papilla correlated with the axonal integrity and demyelination/glia cell impairment of the optic radiation in controls and glaucoma. In NTG the impaired contrast sensitivity is highly variable and is not associated with the condition of the 3rd or 4th neuron, respectively, as compared to POAG. The autocorrelation between individual covariates represents an important element for the judgement of the visual pathway.

[Retinal microangiopathy in arterial hypertension as an early marker of a cerebral macroangiopathy]. / Retinale Mikroangiopathie bei arterieller Hypertonie als Frühzeichen einer zerebralen Makroangiopathie.

HISTORY AND ADMISSION FINDINGS: A 54-year-old man reported having had nonspecific attacks of dizziness. His BMI was 27.7. Since 11 years he had been treated for arterial hypertension and had received oral medication for type 2 diabetes for one year. The latest blood pressure value was 134/109 mm Hg during treatment with a combination of atenolol, chlortalidone und hydralazine-HCl; furthermore hr received simvastatin, metformin, glimepirid und ramipril. A standardized telemedical imaging of the retina ("talkingeyes (®) ") was undertaken, revealing focal and generalized arteriolar narrowing of the retinal vessels and a retinal microinfarction (cotton wool spot) in the right eye. The arterial/venous ratio was decreased to 0.74 in the right and 0.77 in the left eye. INVESTIGATIONS: Optical coherence tomographie (OCT) revealed an ischemic microinfarction of the retina with marked axonal swelling. The digital subtraction angiography of the cerebral vessels revealed a 40 % stenosis of the right internal carotid artery and a proximal, highgrade stenosis of the basilary artery. TREATMENT AND COURSE: Angioplasty with stent insertion of the basilary artery was performed. Long-term observation showed no restenosis and a reduction in the size of the the retinal microinfarct. CONCLUSION: Retinal microinfarctions denote localized retinal areas of hypoxia and underperfusion. They may act as markers of a generalized micro- and macroangiopathy. Patients with severe retinal microangiopathic changes should be examined thoroughly to detect early macroangiopathic changes. These can be treated by interventional procedures thus avoiding irreversible end-organ damages.

[Electronic patient records and teleophthalmology. Part 2: concrete projects in ophthalmology]. / Elektronische Patientenakte und Teleophthalmologie. Teil 2: Konkrete ophthalmologische Projekte.

Electronic storage of patient-related data will replace paper-based patient records in the near future. Because of the high visualization needed in ophthalmology integrated electronic data storage and usage will be very useful. Chronic diseases like glaucoma, macular degeneration and diabetic retinopathy would benefit from long-term data storage and analysis. Unfortunately there are nearly no widely accepted systems available providing these options. Another important point is the simplification of existing diagnostic procedures and nomenclature on an international level. Increasing mobility of patients requires a better portability of existing medical examination data between different physicians. This is the only way to provide continuously high levels of quality in patient care and to simultaneously reduce costs and prevent unnecessary secondary examinations.

A phase Ib study of vosaroxin, an anticancer quinolone derivative, in patients with relapsed or refractory acute leukemia.

This study of vosaroxin evaluated dose-limiting toxicity (DLT), maximum-tolerated dose (MTD), pharmacokinetics (PK), clinical activity and pharmacodynamics in relapsed/refractory leukemia. Dosing was weekly (days 1, 8 and 15) or twice weekly (days 1, 4, 8 and 11). Seventy-three treated patients had a median age of 65 years, 85% had acute myeloid leukemia and 78% had refractory disease. Weekly schedule: 42 patients received 18-90 mg/m(2); MTD was 72 mg/m(2). Twice-weekly schedule: 31 patients received 9-50 mg/m(2); MTD was 40 mg/m(2). DLT was stomatitis; primary non-hematologic toxicity was reversible gastrointestinal symptoms and febrile neutropenia. Thirty-day all-cause mortality was 11%. Five patients had complete or incomplete remissions; median duration was 3.1 months. A morphologic leukemia-free state (bone marrow blast reduction to <5%) occurred in 11 additional patients. Antileukemic activity was associated with total dose or weekly time above 1 µmol/l plasma vosaroxin concentration (P<0.05). Vosaroxin exposure was dose proportional over 9-90 mg/m(2). The average terminal half-life was ~25 h and clearance was non-renal. No induction or inhibition of vosaroxin metabolism was evident. Vosaroxin-induced DNA damage was detected as increased intracellular γH2AX. Vosaroxin had an acceptable safety profile, linear PK and encouraging clinical activity in relapsed/refractory leukemia.

[Electronic patient records and teleophthalmology : part 1: introduction to the various systems and standards]. / Elektronische Patientenakte und Teleophthalmologie : Teil 1: Vorstellung der verschiedenen Systeme und Standards.

Electronic storage of patient-related data will replace paper-based patient records in the near future. Some steps in medical practice can even now not be achieved without electronic data processing. Both systems, conventional paper-based and electronic-based records, have advantages and disadvantages which have to be taken into consideration. The advantages of electronic-based records are e.g. good availability of data, structured storage of data, scientific analysis of long-term data and possible data exchange with colleagues in the context of teleconsultation systems. Problems have to be solved in the field of data security, initial high investment costs and time consumption in learning to use the system as well as in incompatibility of existing IT systems.

[Comparison of early retinal microvascular changes and microalbuminuria as indicators for increased cardioascular risk]. / Vergleich von frühen Veränderungen der retinalen Mikrostrombahn und Mikroalbuminurie als Zeichen eines erhöhten kardiovaskulären Risikos.

INTRODUCTION: Prevention of cardiovascular disease is an important goal in clinical medicine and public health. In the process, the diagnosis of early end-organ damage is a priority beside the treatment of classic cardiovascular risk factors. To achieve this, the ophthalmoscopic examination of the retinal vessels plays a prominent role. Alternatively, the quantification of low quantities of albumin in the urine (microalbuminuria) allows the detection of early vascular damage in the kidney. The question is addressed as to whether these two methods are interchangeable or are rather complementary. PATIENTS AND METHODS: We examined 226 members of the staff of the University Hospital Erlangen who volunteered to participate in a preventive campaign. A comprehensive history was taken, and height, weight and blood pressure were measured. Analysis of serum lipids and determination of the urinary albumin/creatinine ratio were performed. Fotos of the central fundus were taken with a non-mydriatic camera and analysed by an experienced ophthalmologist in a standardised fashion. The risk for cardiovascular mortality within the next ten years was estimated from age, sex, blood pressure and serum cholesterol using the euroSCORE tables for Germany. RESULTS: There was no signficant correlation between the arteriovenous ratio of the retinal vessels and the urinary albumin/creatinine ratio. Neither parameter correlated with the euroSCORE Germany. Arteriovenous crossings and focal narrowing of the retinal vessels were associated signficantly with an elevated euroSCORE risk. CONCLUSIONS: In large population-based studies, the arteriovenous ratio and the urinary albumin/creatinine ratio have been confirmed as markers of cardiovascular risk. In our study, there was no correlation between these two parameters. Thus, they seem to present independent risk markers. The presence of arteriovenous crossings and focal narrowing seems to be linked more closely to the classic cardiovascular risk factors from which the euroSCORE is calculated. The ophathlmolscopic examination of retinal vessels and the analysis of urinary albumin/creatinine ratio seem to complement rather than replace each other.

[Validation of telemedical fundus images from patients with retinopathy]. / Validierung von telemedizinischen Fundusaufnahmen bei Patienten mit Retinopathie.

BACKGROUND: The degree of retinal microangiopathy is important foran estimation of the vascular risk and for the optimisation of therapy in hypertensive and diabetic patients. Retinal microangiopathy may be determined by examination of the retinal fundus. We examined the reliability of the ophthalmoscopic diagnosis and of the telemedical judgement of fundus images in relation to the presence and the degree of retinopathy. PATIENTS AND METHODS: This comparative observational study included 47 inpatient hypertensive and/or diabetic subjects. The fundus was judged ophthalmoscopically and subsequently, a fundus image was generated by use of a KOWA camera. The images were sent to the Interdisciplinary Center of Ophthalmologic Preventive Medicine. The reliability of the two diagnostic methods was calculated for one of the two eyes, which was selected by a random generator. RESULTS: The largest concordance of the two diagnosis methods was achieved, in descending order, for retinal bleeding, stage of diabetic retinopathy and the papilla findings. Additionally, there were no differences for the stage of hypertensive retinopathy und tortuosity. The reliability of arterio-venous nicking related to the right and the left eye was low or absent, respectively. CONCLUSIONS: The teleophthalmologic diagnosis achieves good results as compared to the ophthalmoscopic judgement in relation to retinopathy assessment criteria.

[Prevalence of glaucomatous optic nerve atrophy among a working population in Germany diagnosed by a telemedical approach]. / Telemedizinische Erfassung der Prävalenz der glaukomatösen Optikusatrophie in einer arbeitenden Bevölkerungsgruppe.

PURPOSE: The aim of this study was to determine the prevalence of glaucomatous optic nerve atrophy among a working population in Germany by secondary evaluation of a study conducted to estimate the prevalence of retinal microangiopathic abnormalities by telemedical examination of the retina. PATIENTS AND METHODS: From August 2002 until January 2004 the retina and optic nerve head were examined in 19,294 Caucasians using a non-mydriatic fundus camera (Kowa, nonmyd-alpha 45), which produces colour images with 45 degrees. The images of the retina and optic nerve head were evaluated telemedically by glaucoma specialists in respect to optic nerve pathologies and microangiopathic abnormalities by a standardised procedure. Glaucomatous optic nerve atrophy was diagnosed when specific glaucomatous morphological alterations of the optic nerve head were present. A complete medical history including reported elevated intraocular pressure (IOP) and blood pressure was obtained. RESULTS: The intra-observer and inter-observer reliability were 0.884 and 0.740, respectively. Cronbach's alpha for two evaluation cycles each of two observers was 0.870. The prevalences of glaucomatous optic nerve atrophy in the different age groups were 0.07 % (45 - 49 years), 0.40 % (50 - 54 years), 0.45 % (55 - 59 years) and 0.82 % (60 - 64 years). Age could be established as an important risk factor for glaucomatous optic nerve atrophy, while no influence of gender or family history was found. CONCLUSION: Telemedical evaluation of colour images of the retina and optic nerve acquired by a non-mydriatic fundus camera allows a fast and efficient screening of many subjects with medium reliability.

Cold stimulation induces different responses of ophthalmic artery blood flow velocity depending on baseline blood pressure and gender.

Earlier, we have introduced the spectral index (SI), which was derived from the harmonic content of the blood flow velocity envelope of the ophthalmic artery. SI changed in dependency on the baseline blood pressure (bBP). We now examined SI during sympathetic activation by cold stimulation for 300 s in dependency on bBP to investigate the response to sympathetic neural activity in arterial hypertension. Ten men and 12 women with normal bBP (age, 60.5+/-4.6 years and 61.9+/-7.2 years) and age-adjusted men and women with increased bBP underwent the cold pressor test, including a periodical measurement of blood pressure and blood flow velocity in the ophthalmic artery, the latter by pulsed Doppler sonography. From this, the course of the SI was calculated. During cold stimulation men with increased bBP achieved their SI peak and their systolic blood pressure peak earlier than those with normal bBP (P=0.002 and P=0.035, respectively) and their SI slope was steeper than in normotensive men (P=0.002). Multiple testing showed that the difference of SI decrease between men with normal and increased bBP occurs on average 60 s after the beginning of cold stimulation (P=0.018). These differences were not found between female blood pressure groups, but the results in women may be influenced by antihypertensive treatment of some of the hypertensive women. In conclusion, the SI is useful to evaluate the response to sympathetic activation in hypertensive men but a larger study population should confirm the study results in women.

[Web-based electronic patient record as an instrument for quality assurance within an integrated care concept]. / Webbasierte elektronische Krankenakte im Rahmen eines integrierten Versorgungskonzepts als Instrument der Qualitätssicherung.

OBJECTIVE: A prerequisite for integrated care programmes is the implementation of a communication network meeting quality assurance standards. Against this background the main objective of the integrated care project between the University Eye Hospital Erlangen and the health insurance company AOK Bayern was to evaluate the potential and the acceptance of a web-based electronic patient record in the context of cataract and retinal surgery. METHODS: Standardised modules for capturing pre-, intra- and post-operative data on the basis of clinical pathway guidelines for cataract- and retinal surgery have been developed. There are 6 data sets recorded per patient (1 pre-operative, 1 operative, 4-6 post-operative). For data collection, a web-based communication system (Soarian Integrated Care) has been chosen which meets the high requirements in data security, as well as being easy to handle. This teleconsultation system and the embedded electronic patient record are independent of the software used by respective offices and hospitals. Data transmission and storage were carried out in real-time. RESULTS: At present, 101 private ophthalmologists are taking part in the IGV contract with the University Eye Hospital Erlangen. This corresponds to 52% of all private ophthalmologists in the region. During the period from January 1st 2006 to December 31st 2006, 1844 patients were entered. Complete documentation was achieved in 1390 (75%) of all surgical procedures. For evaluation of this data, a multidimensional report and analysis tool (Cognos) was used. The deviation from target refraction as one quality indicator was in the mean 0.09 diopter. CONCLUSIONS: The web-based patient record used in this project was highly accepted by the private ophthalmologists. However there are still general concerns against the exchange of medical data via the internet. Nevertheless, the web-based patient record is an essential tool for a functional integration between the ambulatory and stationary health-care units. In addition to the telemedicine functions of the system, we achieved the export of the data to a data warehouse system in order to provide a flexible and powerful tool for quality assurance analysis and reporting.

Visual field defect during therapy with valproic-acid.

Visual field defect because of antiepileptic drug (AED) treatment has been widely reported during the clinical application of vigabatrin. But other gamma-aminobutyric acid (GABA)-ergic and non-GABA-ergic AEDs could also affect the visual field with different mechanisms of action. Here we report a case of a 22-year-old female patient, who suffered from bilateral concentric visual field defect during the long-term therapy with valproic-acid (VPA). A VPA-related metabolic dysfunction was found through blood and urine examination. Reduced B-waves were shown by electroretinography and a bilateral concentric visual field defect was confirmed by both manual and automated perimetry. In conclusion, the concentric visual field defect related to VPA treatment is rare but possible.

[Diagnostics and therapy for normal tension glaucoma]. / Diagnostik und Therapie des Normaldruckglaukoms.

Pooled data from "The Baltimore Eye Survey", "The Blue Mountains Eye Study", "The Beaver Dam Eye Study", "The Rotterdam Study" and "The Melbourne VIP" showed a strong age-dependent prevalence of open angle glaucoma. Patients younger than 60 years have a prevalence of open angle glaucoma of less than 1 %. Beginning with the age of 60 the prevalence increases exponentially. The prevalence of open angle glaucoma in persons in the 8(th) age decade reaches up to 5 %. Among these patients, 30-50 % have normal intraocular pressure. The diagnostics and therapy for open angle glaucoma with normal intraocular pressure (IOP), also called normal tension glaucoma, is a complex and often interdisciplinary challenge. Established causative factors for developing a glaucomatous optic nerve atrophy in normal tension glaucoma are: relatively increased IOP, older age, non-dippers (0-10 %) or extreme dippers (> 20 %) concerning nocturnal arterial blood pressure drop, small vessel disease with cardiovascular disease and cerebral microgliosis (white matter lesions), decreased blood flow in the optic nerve head, extreme dip of the optic nerve head blood flow in the morning, cerebral blood flow dysregulation and the epsilon4-allele polymorphism of the apolipoprotein E-gene. Clinical pathways are presented for the diagnostics and therapy for normal tension glaucoma.

[TalkingEyes-and-more]. / [In Process Citation]

To avoid the clinical manifestation of a vascular disease like stroke it is necessary to detect early vascular signs, to begin a therapy before the outbreak of the vascular disease happens. "TalkingEyes-and-more" is an interdisciplinary and quality-assessed program for prevention of vascular diseases. In several "screening-centers" in Germany interested citized were examined by non-invasive and fast methods to estimate the vascular risk. The examinations were performed on site, the medical evaluation of the data and images were performed centrally in the reading center of the Private Center of Preventive Medicine and Eye Diagnostics" in Erlangen by medical doctors. Alterations of the microvessels become often at first visible in retinal vessels. "TalkingEyes-and-more" examined telemedically the retinal vessels by a patented approach regarding microangiopathic abnormalities. In addition other risk factors like arterial blood pressure, intima media thickness of the carotid artery, cholesterol, fasting glucose, extended bodymass index, and others were documented. By these data a risk index is calculated and a proposal for improving the risk factors is generated.

Automated segmentation of the optic nerve head for diagnosis of glaucoma.

Glaucoma is the second most common cause of blindness worldwide. Low awareness and high costs connected to glaucoma are reasons to improve methods of screening and therapy. A well-established method for diagnosis of glaucoma is the examination of the optic nerve head using scanning-laser-tomography. This system acquires and analyzes the surface topography of the optic nerve head. The analysis that leads to a diagnosis of the disease depends on prior manual outlining of the optic nerve head by an experienced ophthalmologist. Our contribution presents a method for optic nerve head segmentation and its validation. The method is based on morphological operations, Hough transform, and an anchored active contour model. The results were validated by comparing the performance of different classifiers on data from a case-control study with contours of the optic nerve head manually outlined by an experienced ophthalmologist. We achieved the following results with respect to glaucoma diagnosis: linear discriminant analysis with 27.7% estimated error rate for automated segmentation (aut) and 26.8% estimated error rate for manual segmentation (man), classification trees with 25.2% (aut) and 22.0% (man) and bootstrap aggregation with 22.2% (aut) and 13.4% (man). It could thus be shown that our approach is suitable for automated diagnosis and screening of glaucoma.

[Telemedical-supported screening of retinal vessels ("talking eyes")]. / Telemedizinisch unterstütztes Screening der retinalen Gefässe ("Talking Eyes").

BACKGROUND: Cerebral and retinal vessels behave similarly under the influence of vascular risk factors. Several groups have shown that retinal microvascular abnormalities represent an independent risk factor with regard to strokes and heart attacks. AIM OF THE STUDY: The aim of this study was to perform a prospective screening examination with regard to retinal microvascular abnormalities as well as an extended vessel diagnosis in a subgroup of patients with lower arteriovenous risk values. METHODS: In the course of a prospective cross-sectional study ("Talking Eyes") between 1.9.2001 and 1.8.2002 a telemedical-supported screening of the retina (study I) was carried out in 7,163 subjects. The patients were selected without any inclusion or exclusion criteria. The mean age was 48.2 +/- 8 years (18 - 83 years) with a sex distribution of 39.2 % females to 60.8 % males. Digital fundus photos of the right and left eyes were taken for all patients. The pictures were taken without pupil dilation using a CANON-NM camera. The pictures and case histories were stored in a central server using web-based software (MedStage, Siemens). In a central reading centre, the arteriovenous ratio of both eyes was determined telemedically using the Parr-Hubbard formula and the retinas subjected to a standardised examination by an ophthalmologist. The retinal risk factor was calculated on the basis of the arteriovenous ration, the presence of microvascular abnormalities and the case history. The reproducibility of measurement of the arteriovenous ratio (Kronbach alpha coefficient) was evaluated by double measurements on 1,332 images. In a subgroup of study I with arteriovenous ratio values < 0.76 (N = 107), an extended vessel diagnosis with measurement of 24-h blood pressure and vessel-relevant blood values (homocysteine, cholesterol, LDL, HDL, CRP, TG, HbA1c) was carried out (study II). RESULTS: Study I: The Kronbach alpha coefficient as a measure of reproducibility amounted to 0.77. The mean arteriovenous ratio of the retinal vessels was 0.83 +/- 0.09 and showed a pronounced age dependence (R = 0.9, p < 0.0001). On multivariate testing the arteriovenous ratio correlated significantly (R = 0.33, p < 0.001) with the factors age, systolic blood pressure, diastolic blood pressure and body mass index. Diastolic blood pressure followed by age had the largest influence. The prevalence of microvascular abnormalities in the right (RE) and left (LE) eyes, respectively were: cotton wool foci RE 0.0015 %, LE 0.003 %, retinal haemorrhage RE 0.1 %, LE 0.1 %, focal stenoses RE 3.4 %, LE 3.4 %, tortuositas vasorum RE 4.1 %, LE 4.0 %, arteriovenous crossing signs RE 11.2 %, LE 11.2 %. On multivariate testing the occurrence of microvascular abnormalities correlated significantly (R = 0.38, p < 0.001) with the factors high blood pressure known from case history, body mass index, and gender. Arterial hypertension had the strongest influence followed by diastolic blood pressure. The calculated retinal risk factor correlated with the prevalence of angina pectoris. Study II: 2/3 of the subjects with arteriovenous risk factor values < 0.76 exhibited pathologically high 24-h blood pressure values. For these patients there were significant correlations between the arteriovenous ratio and the low-density lipoprotein concentration as well as the Framingham risk score. CONCLUSION: In the course of a prospective, telemedical-supported screening examination of the retinal vessels of more than 7,000 subjects the arteriovenous ratio exhibited a strong dependence on age and blood pressure. Among the subjects with lowered arteriovenous ratio values, 2/3 exhibited arterial hypertension in the 24-h blood pressure determination.

[Telematic-assisted self-tonometry (TAS)]. / Telematisch assistierte Selbsttonometrie (TAS).

BACKGROUND: Close supervision of intraocular pressure (IOP) means monitoring an important risk factor for glaucoma. METHOD: After instruction in its use, patients measure their own IOP several times a day with the Drager self-tonometer. The measurements are subsequently transmitted to a server via the telephone keypad and recorded separately for each patient. The software enables statistical evaluation of the pressure levels collected. RESULTS: Up to now 30 of 35 patients transmit measurements or had done so for at least 6 months. Registration of measurement levels covering months and years provides the opportunity for optimizing treatment and hence can be considered a start toward quality assurance in the treatment of glaucoma patients. CONCLUSION: TAS is a cost-efficient method for obtaining long-term profiles of eye pressure. Thus, the possibility exists for early therapeutic intervention in patients at risk. The compliance gained by the close relationship between the physician and the patient represents a positive prognostic factor.