Search results for "Fundus oculi"
showing 7 items of 27 documents
Color Doppler Imaging of the Ocular Ischemic Syndrome
1992
Purpose: This study describes hemodynamic characteristics of the ophthalmic, central retinal, and posterior ciliary arteries in 16 eyes of 11 patients with the ocular ischemic syndrome. Understanding the hemodynamic characteristics of the retrobulbar circulation may elucidate the natural history and pathophysiology of the ocular ischemic syndrome and perhaps form the basis for rational treatment of this condition. Methods: Color Doppler imaging, a procedure that permits rapid noninvasive imaging of the ophthalmic, central retinal, and posterior ciliary arteries, was used to quantitate peak systolic blood flow velocities and vascular resistance (pulsatility index) within these vessels in stu…
A visual framework to create photorealistic retinal vessels for diagnosis purposes
2020
The methods developed in recent years for synthesising an ocular fundus can be been divided into two main categories. The first category of methods involves the development of an anatomical model of the eye, where artificial images are generated using appropriate parameters for modelling the vascular networks and fundus. The second type of method has been made possible by the development of deep learning techniques and improvements in the performance of hardware (especially graphics cards equipped with a large number of cores). The methodology proposed here to produce high-resolution synthetic fundus images is intended to be an alternative to the increasingly widespread use of generative ad…
Delayed Suprachoroidal Hemorrhage After Pars Plana Vitrectomy: Five-Year Results of a Retrospective Multicenter Cohort Study
2015
Purpose To determine the incidence, risk factors, and outcomes of delayed suprachoroidal hemorrhage after vitrectomy. Design Retrospective multicenter cohort study. Methods All consecutive patients who underwent primary vitrectomy, from January 2009 to December 2014, at 4 tertiary vitreoretinal centers in Italy were enrolled. Patient demographics and systemic, ophthalmic, operative, and postoperative data from all centers were extracted from the electronic record system using standardized data collection forms. All eyes that developed delayed suprachoroidal hemorrhage within 48 hours of the end of the vitrectomy were identified as the delayed suprachoroidal hemorrhage group; all other eyes …
Retinal vascular imaging in cardiovascular medicine: New tools for an old examination
2017
The old concept that the eye is the only window through which the body microcirculation can be observed in life easily, safely and repeatedly is part of the cultural baggage of every physician. When Hermann von Helmholtz invented the direct ophthalmoscope in 1850, he opened the door to a non-invasive visualization of human microcirculation in vivo at the retina. Only a few years later, the Scottish ophthalmologist Marcus Gunn documented the close association between retinal changes, and renal and cardiovascular diseases (CVD) in hypertensive patient. In 1939, Keith, Wagener, and Barker showed that the severity of retinal microvascular abnormalities was predictive of mortality in patients wi…
Arterial Hypertension and the Hidden Disease of the Eye: Diagnostic Tools and Therapeutic Strategies.
2022
Hypertension is a major cardiovascular risk factor that is responsible for a heavy burden of morbidity and mortality worldwide. A critical aspect of cardiovascular risk estimation in hypertensive patients depends on the assessment of hypertension-mediated organ damage (HMOD), namely the generalized structural and functional changes in major organs induced by persistently elevated blood pressure values. The vasculature of the eye shares several common structural, functional, and embryological features with that of the heart, brain, and kidney. Since retinal microcirculation offers the unique advantage of being directly accessible to non-invasive and relatively simple investigation tools, the…
Studying hypertension in ocular fundus images using Hausdorff dispersion ordering.
2010
Retinal arterial and vein diameters are altered in individuals at risk of cardiovascular events mainly due to high blood pressure. The measurement of retinal vessel diameters has been proved to reflect individuals' vascular health. Dispersion of such measures which are obtained by means of ocular fundus images is a major factor not usually considered in clinical research. In this paper, a method to evaluate if different levels of clinically relevant covariables induce greater dispersion in retinal arterial and vein diameters is proposed. A multivariate dispersion ordering, the Hausdorff dispersion order, is used to compare the level of dispersion in such diameters for different groups of pa…
Automated Detection of Microaneurysms Using Scale-Adapted Blob Analysis and Semi-Supervised Learning
2014
International audience; Despite several attempts, automated detection of microaneurysm (MA) from digital fundus images still remains to be an open issue. This is due to the subtle nature of MAs against the surrounding tissues. In this paper, the microaneurysm detection problem is modeled as finding interest regions or blobs from an image and an automatic local-scale selection technique is presented. Several scale-adapted region descriptors are then introduced to characterize these blob regions. A semi-supervised based learning approach, which requires few manually annotated learning examples, is also proposed to train a classifier to detect true MAs. The developed system is built using only…