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At least 127 records · Page 7Linked to original sources
PubMed1999

Grid laser treatment of macular edema in macular branch retinal vein occlusion.

AIM: Macular branch retinal vein occlusion (MBRVO) is a subgroup of branch retinal vein occlusion in which the occlusion is limited to a small venous vessel draining a sector of the macular region. The present study aims to evaluate the efficacy of grid laser treatment for macular edema in MBRVO. METHODS: 77 Patients with MBRVO of recent onset were prospectively studied during a 24 month period. Eyes were randomly assigned to a grid laser treatment group and to a control group. Clinical parameters such as visual acuity, presence of macular edema and angiographic features were recorded during the follow-up period. RESULTS: Visual acuity increased significantly in both groups after 3 months of follow-up (p<0.001) and after 1 year of follow-up (p<0.005). No additional improvement was noted at the two year control. There was no statistical difference between the two groups. CONCLUSIONS: The visual prognosis of MBRVO is not improved after grid laser treatment of macular edema. This suggests that sudden ischemic damage to central photoreceptors rather than macular edema is the main factor for permanent visual acuity reduction.

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PubMed1999

Grid laser treatment in macular branch retinal vein occlusion.

BACKGROUND: Macular branch retinal vein occlusion (MBRVO) is a subgroup of branch retinal vein occlusion in which the occlusion is limited to a small venous vessel draining a sector of the macular region. The present study aimed to evaluate prospectively whether grid laser treatment is useful in improving the visual acuity of eyes affected by MBRVO with significant macular edema. METHODS: Ninety-nine patients affected by MBRVO of recent onset were prospectively studied during a 24-month period; eyes were randomly assigned to the control group, the early grid laser treatment group or the delayed grid laser treatment group. Clinical and angiographic features were recorded during the whole follow-up; parameters such as visual acuity and macular edema were carefully evaluated, the latter even by means of stereophotography. RESULTS: With respect to the baseline mean visual acuity values, a statistically significant improvement was noted at the 3-month follow-up and at the 1-year follow-up. No additional improvement was noted at the 2-year follow-up. No statistically significant difference was found between the treated groups and the control group. CONCLUSIONS: We hypothesize that the abrupt ischemic damage subsequent to MBRVO is the main factor causing the central function impairment. Grid laser treatment is not able to reduce the macular edema more than the natural evolution, and does not improve visual acuity.

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PubMed2002

Direct tissue plasminogen activator administration through a microinjection device in a pig model of retinal vein thrombosis.

PURPOSE: This study sought to analyze the changes to clots and retinal tissue following direct infusion of tissue plasminogen activator (tPA) at different rates to the obstructed area of the retinal vein in an experimental animal model of retinal vein occlusion. METHODS: The miniature pigs, which underwent unilateral retinal vein thrombosis generated by a combination of light illumination of the retinal vein and I.V. administration of rose Bengal, were randomly divided into two groups. In the experimental group (n = 45), balanced salt solutions + tPA were infused into the obstructed retinal vein at different rates (30,60, and 80 ml/h) for 20 minutes (15 pigs in each subgroups). In the control group (n = 5), balanced salt solutions without tPA were infused. Retinal tissue and clots were evaluated by fundus photographic and histopathologic analysis. RESULTS: Clot lysis occurred in 2/15, 9/15, and 10/15 pigs respectively following the 30, 60, and 80 ml/h tPA infusion. Exudative retinal detachment appeared in 12/15 pigs after infusion of tPa at a rate of 80 ml/h. Retinal histopathology and transmission electron microscopy showed that endothelial cell tight junctions of retinal vein and capillaries were injured in pigs receiving the 80 ml/h tPA infusion. CONCLUSION: Experiments with our pig model suggests that the optimal infusion rate for the treatment of retinal vein thrombosis by direct tPA infusion is 60 ml/h for 20 minutes.

Animals↗
PubMed1998

Retinal blood flow measurements in branch retinal vein occlusion using scanning laser Doppler flowmetry.

PURPOSE: To determine capillary blood flow measurements in eyes with branch retinal vein occlusion using a scanning laser Doppler flowmeter. METHODS: Retinal capillary blood flow in branch retinal vein occlusion areas and corresponding ipsilateral nonbranch retinal vein occlusion areas, 11 equivalent areas of the contralateral fellow eye of 12 consecutive untreated branch retinal vein occlusion patients, and 16 eyes of 11 age-matched normal control subjects were measured with scanning laser Doppler flowmetry. A template consisting of eight squares, each with a field of 100 x 100 microm (10 x 10 pixel) with space interval of 500 microm equidistant horizontally and vertically was used to obtain blood flow measurements in all subjects. Mean blood volume, flow, and velocity were obtained by averaging the mean values measured in each field. We avoided measurement over large retinal vessels to prevent the aliasing artifact of blood cells from moving faster than the sampling frequency. RESULTS: Branch retinal vein occlusion areas have significantly decreased microvascular blood volume (P = .0009), flow (P = .02), and velocity (P = .016) compared with ipsilateral nonbranch retinal vein occlusion areas in the same eye. Branch retinal vein occlusion areas also have decreased blood volume (P = .001), flow (P = .0042), and velocity (P = .0044) compared with areas of contralateral fellow eyes of branch retinal vein occlusion subjects. Branch retinal vein occlusion areas have significantly decreased blood volume (P = .0012), flow (P = .008), and velocity (P = .02) compared with age-matched normal areas. CONCLUSION: Average retinal blood volume, flow, and velocity in areas of branch retinal vein occlusion are significantly lower than in healthy retinas. The ability to noninvasively measure hemodynamic changes in the retinal capillary bed may be relevant to development of new therapies for retinovascular disease.

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PubMed2000

Initial color Doppler findings in retinal vein occlusion.

PURPOSE: We assessed early hemodynamic characteristics of various types of retinal vein occlusion using color Doppler imaging and spectral analysis. METHODS: We measured the maximum systolic and diastolic blood flow velocities and the resistance index (RI) in the central retinal artery and the maximum and minimum blood flow velocities in the central retinal vein of affected eyes and contralateral unaffected eyes in 102 adults (63 men and 39 women; mean age, 61 +/- 14.6 years) who presented with retinal vein occlusion. Sixty-three control subjects (27 men and 36 women; mean age, 50 +/- 22.1 years) were also investigated. RESULTS: No significant differences in hemodynamic characteristics were found between the control subjects' eyes and the patients' unaffected eyes. In the 18 cases of ischemic central retinal vein occlusion, the mean diastolic arterial flow velocity (p = 0.005) and venous flow velocity (p < 0.04) were lower and the mean RI was higher (p = 0. 0002) in the affected eyes than in the unaffected contralateral eyes. In the 51 cases of nonischemic central retinal vein occlusion, the mean diastolic arterial flow velocity (p < 0.0001) and venous flow velocity (p < 0.0001) also were lower and the mean RI (p < 0.0001) was higher in the affected eyes than in the unaffected contralateral eyes. These variables were different in the ischemic versus nonischemic types of central retinal vein occlusion. In the 33 cases of branch retinal vein occlusion, no significant differences were observed in arterial or venous blood flow velocities in the affected versus unaffected eyes. The mean RI in the affected eyes was significantly higher (p = 0.009) in patients with central versus branch retinal vein occlusion. CONCLUSIONS: These results suggest that previous arterial disorders were not involved in the pathogenesis of central retinal vein occlusion in these patients. The findings also support the value of Doppler imaging and spectral analysis in the diagnosis and evaluation of retinal vein occlusion and confirm the involvement of arterial flow in venous occlusion.

Adult↗
PubMed1985

Medical conditions underlying recurrence of retinal vein occlusion.

Seventeen patients with recurrent retinal vein occlusion were investigated for underlying medical conditions and compared with 61 patients with single retinal vein occlusion (26 with central, 35 with branch vein occlusion). The two study groups were comparable for age, sex, and weight. Patients with recurrence had a significantly increased prevalence rate of hypertension (88% versus 48%: p less than 0.01), with a trend to increased hyperlipidaemia (47% versus 33%) compared with patients with a single episode. A significantly raised mean systolic (p less than 0.05) but not diastolic blood pressure was found in patients with recurrence. Other cardiovascular risk factors in patients with recurrence were also found and included lower mean levels of high density lipoprotein (HDL)-cholesterol (p less than 0.02) and the HDL2 subfraction (p less than 0.001), and a significantly increased proportion of patients with regular alcohol intake (p less than 0.01). We conclude that hypertension and hyperlipidaemia with an increase in other cardiovascular risk factors are commonly found in patients with recurrent retinal vein occlusion and may therefore be important aetiological factors. The possible benefits of treatment of these underlying conditions to prevent recurrence need to be assessed in well designed prospective studies.

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PubMedDate not supplied

Central retinal vein occlusion in young adults.

Central retinal vein occlusion (CRVO) is usually seen in older adults and is often associated with systemic vascular disease. CRVO can be seen in young adults, and although it is occasionally associated with a systemic disease, in the majority of cases it occurs in an otherwise healthy patient with no known systemic disease or ocular problem. Inflammation of the central retinal vein has been proposed as a cause of the occlusion in young adults and for that reason it has been called papillophlebitis. The appearance of unilateral optic disc edema, dilatation, and tortuosity of the major retinal veins with a variable amount of retinal hemorrhage in young, healthy adults with complaints of blurred vision or photopsias has been called, in addition to papillophlebitis, benign retinal vasculitis, optic disc vasculitis, nonischemic CRVO, big blind spot syndrome, and presumed phlebitis of the optic disc. An approach to the diagnostic evaluation of the young adult with CRVO is presented. Although most eyes recover vision to better than 20/40, about one-fifth have significant visual loss, and many suffer ocular sequelae. Many treatment modalities have been tried for this entity, but no conclusive evidence exists that any treatment alters its natural history.

Adolescent↗
PubMed1983

Evaluation of a patient with central retinal vein occlusion.

Patients suffering a central retinal vein occlusion should be evaluated for conditions that promote and/or contribute to the formation of a thrombosis in the central retinal vein. These conditions include alterations of blood flow, altered viscosity of the blood, abnormalities of coagulation, and abnormalities of vessel walls. Patients with either a partial or complete central retinal vein occlusion have similarities in the age of onset, associated systemic findings, and laboratory data. At the time of onset, 90% of patients are older than 50 years. Seventy-four percent of patients will have symptoms or signs of associated systemic vascular disease (ie, hypertension, arteriosclerotic heart disease, and diabetes mellitus.) The most common laboratory findings include elevated blood lipids, abnormalities of glucose tolerance testing, and abnormalities of protein chemistries. Evaluation should include both a complete ocular and medical examination with appropriate laboratory tests and special studies. Assessment of central retinal venous pressure may be helpful in identifying those patients who have a severe, complete thrombosis and are at significant risk to develop anterior segment neovascularization.

Adult↗
PubMed2002

High prevalence of resistance to APC in young patients with retinal vein occlusion.

Resistance to activated protein C (APC) is among the coagulation disorders that have been implicated in retinal vein occlusion. However, since retinal vascular occlusions may be due to a combination of several mechanisms, the question of whether thrombophilic anomalies are pathogenic for this disorder remains controversial. In the current study, we investigated the prevalence of APC resistance in patients with retinal vein occlusion with reference to age and various cardiovascular risk factors. A cohort of 142 consecutive patients with retinal vein occlusion and a control group of 128 subjects matched for age, sex and several risk factors were screened for resistance to APC. Both cohorts were divided into two subgroups, according to the patient's age (< or =45 or >45 years) at the time of the retinal vein occlusion or a previous thromboembolic event. The proportion of individuals with resistance to APC was higher in the patient group (13 of 142; 9.1%) when compared to controls (6 of 128; 4.7%). Moreover, patient age < or =45 years by the time of the retinal vein occlusion or a previous thromboembolic event was significantly associated with a high prevalence of APC resistance (17%). By contrast, resistance to APC was present in 5 of 95 cases (5.3%) in the patient group >45 years and in 4 of 83 (4.8%) young controls. Our results indicate that APC resistance is highly prevalent in patients with retinal vein occlusion at age < or =45 years and/or with a history of thrombosis at this age. By contrast, the prevalence of APC resistance in patients who suffered a retinal vein occlusion when they were older than 45 years and had no history of thromboembolism appears to be similar to that seen in healthy control subjects or in the normal population. Selective screening may be helpful in identifying retinal vein occlusion patients with thrombophilic defects.

Activated Protein C Resistance↗
PubMed1976

So-called "central retinal vein occlusion". I. Pathogenesis, terminology, clinical features.

Pathogenesis of occlusion of the central retinal vessels, based on experimental and clinical findings, is discussed. It suggests that the so-called "central retinal vein occlusion" represents not only occlusion of the central retinal vein but also retinal arterial ischemia. Based on this pathogenesis the following terminology is recommended for central retinal vascular occlusion: (a) Ischemic retinopathy is due to occlusion of the central retinal artery. (b) Venous stasis retinopathy is due to occlusion of the central retinal vein alone. (c) Hemorrhagic retinopathy is due to occlusion of the central retinal vein associated with retinal ischemia. Clinical findings of (b) and (c) are compared which indicate that the two conditions are distinct entities and unfortunately so far have been dumped under a common heading of so-called "central retinal vein occlusions". Such a distinction is extremely important before any attempts are made to evaluate their natural history or effects of any therapy on them.

Humans↗
PubMed1983

beta-thromboglobulin and platelet factor 4 levels in retinal vein occlusion.

Fifty-six patients with retinal vein occlusion--35 with central and 21 with branch vein occlusion--were investigated for comparison with an age and sex matched control group. Mean levels of beta-thromboglobulin and platelet factor 4 were significantly higher (p less than 0.001) in both the group with central and the group with branch retinal vein occlusion than in the control group. A significant increase of beta-thromboglobulin (p less than 0.001) was also found in the retinal vein occlusion group in those patients who were not hyperlipidaemic or diabetic (n = 39). Weak correlations were found between levels of lipoprotein cholesterol and plasma beta-thromboglobulin. Increased platelet aggregation may contribute to the aetiology of retinal vein occlusion.

Beta-Globulins↗
PubMedDate not supplied

Central retinal vein occlusion: review of management.

Central retinal vein occlusion is usually a disease of the elderly and is often associated with systemic vascular disease, e.g., hypertension, diabetes mellitus, arteriosclerotic vascular disease. Younger patients, especially those less than 45 years of age, with retinal vein occlusion should be evaluated carefully for the possibility of an underlying thrombotic tendency. The authors describe the ocular manifestations, pathogenesis, associated conditions, patient evaluation, and treatment of patients with central retinal vein occlusion.

Age Factors↗
PubMed1998

[Measurement of retinal blood flow velocity by scanning laser ophthalmoscopic fluorescein fundus angiography in experimental retinal vein obstruction].

To study the role of arterial blood dynamics in the thrombogenesis of thrombin-induced experimental retinal vein obstruction, the retinal blood flow velocity was evaluated using scanning laser ophthalmoscopic fluorescein videoangiography in an experimental rabbit retinal vein obstruction model. Retinal vein obstruction was made by transadventitial direct instillation of thrombin to the retinal vessels from the vitreous side. The blood flow velocity in the retinal artery and vein was estimated by measuring the passing velocity of the flow head of the dye bolus and venous filling time, respectively. 23 animals were treated with thrombin and compared with 18 controls not treated. In the control group retinal artery blood flow velocity and retinal venous fluorescein filling time was 5.3 +/- 1.1 mm/sec (mean +/- standard deviation) and 6.2 +/- 1.2 sec, respectively. In the treated group the values were 5.7 +/- 1.3 mm/sec and 5.8 +/- 1.0 sec before the thrombin administration, and 3.0 +/- 0.9 mm/sec at 24 hours after its administration, and 5.7 +/- 2.0 sec and 4.0 +/- 1.5 mm/sec and 4.5 +/- 1.4 sec at 48 hours after the administration. These results indicate that a decrease in retinal artery blood flow velocity is strongly involved in the thrombogenesis in thrombin-induced experimental retinal vein obstruction.

Animals↗
PubMed2002

[Retinal vein occlusion and carotid Doppler imaging].

PURPOSE: To investigate retinal vein occlusion with B-mode ultrasonography carotid and color Doppler imaging. METHODS: In 223 patients (225 eyes) presenting with retinal vein occlusion, we retrospectively investigated vascular risk factors (hypertension, diabetes, hyperlipidemia, cardiovascular history, smoking, and glaucoma), standard laboratory tests, and color Doppler imaging of the carotid artery. RESULTS: The data from 106 women (47.54%) and 117 men (52.46%), with a mean age of 65 years, were studied, with 169 patients presenting a central retinal vein occlusion (CRVO) and 56 a branch retinal vein occlusion (BRVO). Thirteen patients (6%) had significant carotid artery stenosis (>=70%), which was the single etiology. Forty patients (18%) had nonsignificant carotid artery stenosis (<70%) with a risk of embolism production. Such carotid artery lesions found in color Doppler imaging in the RVO investigations were significantly more frequent in older patients (>65 years) who presented at least two RVO risk factors (p<0.001). CONCLUSION: This study has shown the the advantages of carotid Doppler imaging in retinal vein occlusion.

Adult↗
PubMed1996

Laser therapy for central retinal vein obstruction.

The Collaborative Central Retinal Vein Occlusion Study has recently reported information on the early natural history of central vein occlusion that includes a 16% conversion of perfusion to nonperfusion within the first 4 months. The Collaborative Central Vein Occlusion Study randomized trial of laser photocoagulation for macular edema and for the management of iris neovascularization suggested that grid laser photocoagulation is not useful for the improvement of visual acuity that is decreased because of perfused macular edema and that iris neovascularization is best managed by applying panretinal photocoagulation after the first appearance of iris neovascularization. A recent report has suggested that chorioretinal venous anastomosis can be achieved in some patients with vein occlusion to permit venous outflow through the choroid, lessen the likelihood of progression to ischemia, and improve visual acuity by lessening macular edema.

Fluorescein Angiography↗
PubMed2005

Protein Z levels and central retinal vein or artery occlusion.

OBJECTIVES: Central retinal vein occlusion (CRVO) and central retinal artery occlusion (CRAO) are common disorders associated with risk factors for atherosclerosis. Protein Z is a cofactor for the inactivation of activated factor X (Xa) by the protein Z dependent protease inhibitor. Protein Z deficiency was recently linked to increased risk of arterial thrombosis. We investigated whether CRVO and CRAO are associated with low protein Z levels. PATIENTS AND METHODS: Patients with CRVO, CRAO or recurrent branch retinal vein occlusion were recruited to the study. Protein Z level, lupus anticoagulant (LAC), anticardiolipin antibodies (ACA) and activated protein C resistance (APCR) were determined in plasma from patients (n = 36) and healthy controls (n = 42). RESULTS: Thirty patients in the study group had traditional risk factors for retinal vessel occlusion and six patients had none. There was no significant difference in protein Z levels between the whole study group patients and controls (1995 +/- 810 vs. 2010 +/- 603 ng/mL, P = 0.922). However, patients with no risk factors for retinal vessel occlusion had significantly lower protein Z levels than controls (1379 +/- 682 vs. 2010 +/- 603 ng/mL, P = 0.022). Positive LAC was found in six patients and one control subject (P = 0.04). There were three patients and one control subject with abnormal APCR (P = 0.3) and none with positive ACA. Low protein Z level (lower than fifth percentile of control) was not associated with the presence of LAC or APCR. CONCLUSION: Low protein Z level may be another risk factor for retinal vessel occlusion in patients without traditional risk factors for these disorders.

Adult↗
PubMed1997

Axial length as a risk factor to branch retinal vein occlusion.

PURPOSE: To determine whether axial length is a factor in branch retinal vein occlusion. METHODS: Axial length measurements in a group of 24 patients with a unilateral branch retinal vein occlusion were compared with the axial length measurements in a control group. Axial length measurements were taken with an A-scan; affected and unaffected eyes were measured. The control group consisted of 24 individuals who matched the patients in the branch retinal vein occlusion group in age, systemic hypertension status, and diabetes mellitus status. RESULTS: The affected and fellow eye in patients in the branch retinal vein occlusion group did not differ statistically in axial length (P = 0.26). The mean axial length of affected eyes in the branch retinal vein occlusion group was 22.76 +/- 0.92 mm, and the mean axial length of control eyes was 23.36 +/- 1.08 mm. The difference in axial length between the eyes with a branch retinal vein occlusion and the eyes in the control group was statistically significant (P = 0.023). CONCLUSION: The axial length of affected eyes of patients with branch retinal vein occlusion was on average 0.60 mm shorter than that of eyes of matched controls (95% confidence interval, 0.30-0.90 mm). The shorter axial length could be a local risk factor in the pathogenesis of a branch retinal vein occlusion.

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PubMed2005

[Aspects of outcome and therapy of edematous branch retinal vein occlusion].

The main cause of oedematous branch retinal vein occlusion (BRVO) vision loss is macular oedema persistence. We studied 18 patients having oedematous branch retinal vein occlusion. An ophthalmologic exam completed with angiography and etiologic assessment were performed. Argon Laser macular grid photocoagulation was performed in 11 eyes where macular oedema had persisted for over 3 months with visual acuity under 5/10. In 45% of cases, occlusion interests superotemporal vein. Atherosclerosis risk factors are found in 88% of cases. The course was spontaneously favourable in 39% of cases. Improvement of visual acuity was obtained in 36% of cases treated with laser photocoagulation. Oedematous branch retinal vein occlusion outcome is variable; it can be favourable if veino-veinous anastomosis develops rapidly, or unfavourable with macular edema persistence and decreased visual acuity. In the later case, grid macular phototcoagulation should be performed leading to macular edema regression. So, macular edema secondary to branch retinal vein occlusion can disappear spontaneously and needs laser treatment only if it persists.

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