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Results for “RETINAL VESSELS”

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At least 307 records · Page 17Linked to original sources
PubMed2004

Prospective cohort study of retinal vessel diameters and risk of hypertension.

OBJECTIVE: To examine the relation between diameters of the retinal arterioles and 10 year incidence of hypertension. DESIGN: Population based prospective cohort study. SETTING: Beaver Dam eye study. PARTICIPANTS: 2451 normotensive people aged 43 to 84 years. MAIN OUTCOME MEASURES: Diameters of retinal arterioles and venules measured from digitised photographs of the retina taken at baseline. Measurements summarised as the arteriole:venule ratio, with a lower ratio indicating smaller arteriolar diameters. Incident hypertension, defined as systolic blood pressure > or =140 mm Hg, diastolic blood pressure > or =90 mm Hg, or use of antihypertensive drugs during follow up. RESULTS: 721 participants developed hypertension over a 10 year period. Those with lower arteriole:venule ratio had a higher cumulative incidence of hypertension (incidences of 17.4%, 24.1%, 31.0%, and 45.1%, respectively, for decreasing quarters of distribution of arteriole:venule ratio). After adjustment for age and sex, participants with arteriole:venule ratios in the lowest quarter had a threefold higher risk of hypertension (odds ratio 2.95, 95% confidence interval 2.77 to 3.88) than those with ratios in the highest quarter. This association remained significant after further adjustment for baseline systolic and diastolic blood pressure and other risk factors (1.82, 1.39 to 2.40, for lowest versus highest ratio quarters). CONCLUSIONS: Narrowed retinal arterioles are associated with long term risk of hypertension, suggesting that structural alterations of the microvasculature may be linked to the development of hypertension.

Adult↗
PubMed1992

Computerized digital image analysis of retinal vessel density: application to normoxic and hyperoxic rearing of the newborn rat.

Because of the inherent nature of existing techniques for vascular assessment of the retina, quantitative rigor has been difficult to attain. Computer imaging has now made possible measurement of oxygen-induced alterations in retinal blood vessels that is precise, accurate and repeatable. Newborn rats were exposed to 80% oxygen for 14 days as an animal model for retinopathy of prematurity (ROP). Ink perfusion, followed by retinal dissection, yielded silhouettes of the retinal vascular network. These images were digitized and enhanced by the MegaVision 1024XM imaging system in order to facilitate measuring extent of vasculature and capillary density. Mean grey levels, or 'mu', were 33.1 +/- 3.4 and 20.1 +/- 3.5 for room air- and oxygen-reared rats, respectively. These values are directly proportional to the fraction of the overall image that is vascular material, and, therefore, describe the extent of vaso-obliteration resulting from the oxygen exposure. The values were subsequently converted to square millimeters of vessel area to facilitate comparison to past and future studies. Oxygen rearing does not effect retinal area, but decreases retinal artery and vein diameter and decreases the linear extent of vessels toward the retinal periphery.

Animals↗
PubMed2006

Risk factors for conjunctival and retinal vessel alterations in sickle cell disease.

PURPOSE: The aim of this study was to clarify whether the clinical, laboratory and genetic aspects of sickle cell disease (SCD) influence the occurrence of vessel alterations in the conjunctiva and retina. METHODS: A total of 102 SCD patients underwent biomicroscopical and retinal examination, in addition to evaluations of haemoglobin (Hb) and haematocrit (Ht) levels, fetal haemoglobin (HbF) estimations, serum creatinine and albuminuria levels, glomerular filtration rate (GFR) values, phenotypes, beta-globin gene haplotypes and alpha-thalassaemia. The relationship between ocular vessel alterations and clinical, laboratory and genetic features were evaluated using chi-squared or Fisher tests and logistic regression analysis. In 13 patients on enalapril treatment, a second ophthalmological evaluation was performed after a 12-month period to evaluate the longitudinal effect of the drug on ocular vessels. RESULTS: Conjunctival vessel alteration (CVA) was not influenced by age, gender, HbF estimation, serum creatinine and albuminuria levels, GFR values, beta-globin gene haplotypes or alpha-thalassaemia. However, increased frequencies of CVA were found in patients with Hb </= 9.0 g/dl, Ht </= 26.7% and sickle cell anaemia (SS) phenotype. Retinal vessel alteration (RVA) was identified only in patients aged 17 years or older. Enalapril did not demonstrate ocular vessel amelioration after 12-months of daily use. CONCLUSION: The results indicate that lower Hb and Ht levels and SS phenotype are risk factors for CVA, and age over 17 years may be risk factors for RVA in SCD patients.

Adult↗