Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RETINAL VESSELS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed2006

Multifractal analysis of human retinal vessels.

In this paper, it is shown that vascular structures of the human retina represent geometrical multifractals, characterized by a hierarchy of exponents rather then a single fractal dimension. A number of retinal images from the STARE database are analyzed, corresponding to both normal and pathological states of the retina. In all studied cases, a clearly multifractal behavior is observed, where capacity dimension is always found to be larger then the information dimension, which is in turn always larger then the correlation dimension, all the three being significantly lower then the diffusion limited aggregation (DLA) fractal dimension. We also observe a tendency of images corresponding to the pathological states of the retina to have lower generalized dimensions and a shifted spectrum range, in comparison with the normal cases.

Algorithms↗
PubMed1981

Morphometric studies of pancreatic islets and retinal vessels of rats with streptozotocin-induced latent diabetes.

Latent diabetes was induced in rats by injecting subdiabetogenic doses of streptozotocin. Four months later, the pancreas was examined and morphology, number and size of Langerhans islets were studied and compared with those of control and overt diabetic animals. In latent diabetics and in diabetics, islet surface per unit pancreas surface was significantly lower (p less than 0.01) than in controls. Immunoreactive insulin in beta cells was visualized by the peroxidase reaction and quantitated by densitometry. Assuming insulin in islets of controls equal to 100%, insulin in islets of latent diabetic rats was reduced to 38% (p less than 0.05) and in diabetics to 6% (p less than 0.01). Differences between latent and overt diabetics were not significant. At the same time occurrence of microangiopathy was taken in consideration and the basement membrane thickness of retinal capillaries was measured on electron micrographs by means of an image analyzer. Compared to controls, retinal capillary basement membranes of latent diabetics had increased by 49% (p = 0.01) and of diabetics by 68% (p less than 0.01). Differences between latent diabetics and diabetics were not significant. These observations demonstrate the induction of microangiopathic changes in rats in absence of hyperglycemia and of a genetic prediabetic disposition. Other mechanisms, possibly related to the induced islet abnormality, may be involved in the basement membrane thickening.

Animals↗
PubMed1993

Retinal telangiectasis and proliferation of the retinal vessels in a family.

A 20-year-old woman presented with a marked proliferative retinopathy of the entire central region of the retina in both eyes, with veil-like epiretinal gliovascular membranes and isolated spots of haemorrhaging. The outer region of the retina was unremarkable. Her 49-year-old mother showed perimacular telangiectases in both eyes. The vascular system of both patients were medically sound, and, in particular, the blood pressure, blood sugar and blood picture were normal, with no signs of heart, kidney, lung or liver disease. The first patient had been a heavy smoker for 6 months, and the second did not smoke. The 84-year-old mother of the second patient was blind following bilateral Horton's temporal arteritis.

Adult↗
PubMed2005

Do complaints of amaurosis fugax and blurred vision after transcatheter device closure of atrial septal defect indicate microemboli to retinal vessels?

Atrial septal defect (ASD) is a common diagnosis in young adults with congenital heart disease. The aim of this study was to determine if ocular symptoms following percutaneous treatment are due to microemboli. The study group included 20 adult patients (9 men, 11 women, mean age 57.2 years) with ASD who had undergone successful closure with the Amplatzer occluder. The patients were treated with aspirin or warfarin during 6 months after the procedure. All were evaluated neurologically and an ocular medical history was obtained. Ocular examination included the 120-point Humphrey visual field. Transcranial Doppler (TCD) was performed to monitor the middle cerebral artery. Two patients complained of amaurosis fugax at 1 and 3 months after the procedure, and two patients complained of blurred vision at 3 and 4 months after the procedure. TCD performed for 45 minutes within 24 hours of the visual complaints revealed no abnormalities. In all patients, the neurological and ocular examinations, including the visual field test, were normal. In conclusion, microembolic events could not be demonstrated to be the cause of the ocular complaints in patients with ASD treated with Amplatzer occluder. Further studies in larger samples are needed to confirm these results.

Adult↗