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At least 109 records · Page 6Linked to original sources
PubMed1998

The distribution of angioarchitectural changes within the vicinity of the arteriovenous crossing in branch retinal vein occlusion.

OBJECTIVE: Branch retinal vein occlusions (BRVOs) are known to occur most commonly in the vicinity of arteriovenous (A/V) crossings. The authors aimed to identify types of venous wall abnormalities in BRVO and document their position in relation to the A/V crossing. DESIGN: A retrospective review of the color photographs and fluorescein angiograms from the most recent 110 patients with first- or second-order BRVO was performed. MAIN OUTCOME MEASURES: The films were examined for the presence of angioarchitectural changes of specified type within one-quarter disk diameter of the A/V crossing involved in the BRVO. The specific changes noted were fluorescein leakage, presumed thrombi, and flow abnormalities, which were recorded along with their position in relation to the A/V crossing. RESULTS: Of the 110 patients diagnosed with BRVO, 59 had photography of satisfactory quality. Forty-one (70%) of these 59 patients had venous lesions, of which significantly more (chi-square -5.74, P < 0.02) were downstream (56%) than upstream (12%) from the A/V crossing. Thirty-two percent were upstream and downstream. Of the hemodynamic changes seen, 49% had late venous phase leakage of fluorescein, 85% had abnormal flow, and 7% had presumed thrombi. All thrombi seen were downstream. CONCLUSIONS: Venous lesions in the vicinity of the A/V crossing commonly are seen in BRVO, most of which occur downstream. This suggests that the venous narrowing at the crossing may induce downstream hemodynamic changes predisposing to endothelial damage and thrombus generation.

Arteriovenous Malformations↗
PubMed2006

Ophthalmodynamometric differences between ischemic vs nonischemic retinal vein occlusion.

PURPOSE: To estimate the central retinal vein pressure in patients with ischemic vs nonischemic central retinal vein occlusion (CRVO). DESIGN: Prospective clinical observational comparative study. METHODS: The study included 28 patients with CRVO, either of the ischemic type (n = 7) or the nonischemic type (n = 21). The control group consisted of 38 subjects without retinal disease. A new ophthalmodynamometer consisting of a Goldmann contact lens fitted with a pressure sensor into the holding grip of the contact lens, was used to indirectly estimate the central retinal artery and vein pressure. RESULTS: Central retinal vein pressure was significantly higher in the ischemic CRVO group than in the nonischemic CRVO group (91.5 +/- 30.1 arbitrary units vs 52.4 +/- 32.5 arbitrary units; P = .014), in which it was significantly (P < .001) higher than in the control group (4.8 +/- 8.1 arbitrary units). Central retinal vein pressure was higher than the diastolic central retinal artery pressure significantly (P = .039) more frequently in the ischemic CRVO group (7/7 or 100%) than in the nonischemic CRVO group (8/21 or 38%) or the control group (0/38; P < .001). Central retinal artery pressure was significantly (P = .017) lower in the ischemic CRVO group (46.0 +/- 10.6 arbitrary units) than in the nonischemic CRVO group (64.5 +/- 22.8 arbitrary units), in which it was significantly (P = .016) lower than in the control group (79.9 +/- 22.3 arbitrary units). CONCLUSIONS: Ophthalmodynamometric estimation of the retinal vein pressure may be helpful for the differentiation between the ischemic vs nonischemic type of CRVO. In the ischemic type, vein pulsations were usually observed at supradiastolic arterial values.

Adult↗
PubMed1995

Retinal circulation times in branch retinal vein occlusion.

To investigate the retinal hemodynamics in branch retinal vein occlusion (BRVO), we measured retinal circulation times using scanning laser ophthalmoscope (SLO) and studied their relationships with clinical findings. Arm-retina time (ART) and arteriovenous passage time (AVP) were measured in 30 eyes of 30 patients. Mean ART was 13.07 seconds. ART showed no difference in relation to sex and systemic diseases, but increased with age. Mean AVPs were 3.00 sec. and 3.39 sec. in superotemporal and inferotemporal BRVO, respectively. AVPs were delayed significantly in occluded branch of retinal veins. AVP was delayed three-fold when the area of capillary nonperfusion was over 6 disc area, but showed no difference according to the duration of disease or macular edema. These results suggest that SLO may be a useful tool for studying retinal hemodynamics in BRVO.

Adult↗
PubMed2002

Follow up by colour Doppler imaging of 102 patients with retinal vein occlusion over 1 year.

BACKGROUND/AIM: Retinal vein occlusion (RVO) is one of the most frequent ocular vascular diseases and leads to severe vision impairment. Colour Doppler imaging (CDI) is the first method which allows distinct evaluation of arterial and venous velocities in RVO. CDI is valuable for diagnosis of RVO and shows the effects of isovolaemic haemodilution. Patients with RVO were monitored by CDI for 1 year in order to clarify venous and arterial involvement in the pathogenesis of this disease. METHODS: Patients with RVO were monitored prospectively for 1 year with clinical examinations, fluorescein angiography, and CDI every 3 months. 102 adults referred for RVO for less than 2 months were enrolled. Unaffected eyes were used as control. The maximum systolic and diastolic flow velocities and the resistance index (RI) were measured in the central retinal artery (CRA) and the maximum and minimum blood flow velocities in the central retinal vein (CRV). RESULTS: During the year of observation, branch retinal vein occlusion (BRVO), ischaemic central retinal vein occlusion (CRVO), and non-ischaemic CRVO had a distinct pattern of venous velocity changes. BRVO had a similar profile to that observed in controls. Venous velocities were continuously lower in central forms, with the lowest values in ischaemic occlusion. In contrast, a brief decrease in arterial diastolic velocity was observed in ischaemic CRVO at presentation, correlated with arteriovenous passage time on fluorescein angiography, but with rapid normalisation. CONCLUSIONS: CDI findings were correlated with the type of RVO at all times during follow up. CDI showed persistent impairment of central venous velocity in CRVO whereas there was a fast initial values recovery of the arterial velocity. These results using CDI show strong evidence of a primary venous mechanism in RVO.

Adult↗
PubMed1999

Cilioretinal artery occlusion with central retinal vein occlusion.

BACKGROUND: Combined cilioretinal artery and retinal vein occlusions are infrequently documented retinal vascular disorders of speculative origin. Occlusion of the cilioretinal artery is believed to result from either mechanical compression of the artery as a result of an increase in venous pressure or from a reduction in perfusion pressure in both the cilioretinal and retinal arteries. The ophthalmoscopic and angiographic features of this condition are reviewed. CASE REPORTS: Two cases of cilioretinal artery occlusion after central retinal vein occlusion are presented, one of which evolved to the development of iris neovascularization. DISCUSSION: The incidence of cilioretinal artery occlusions due to central retinal vein occlusions is infrequently reported in the literature. Excluding those with chronic cystoid macular edema, most patients have a favorable visual outcome. It is possible that the incidence of combined cilioretinal artery and central retinal vein occlusions is grossly underestimated.

Adult↗
PubMed1993

Hyperhomocysteinemia in retinal artery and retinal vein occlusion.

In 19 patients who had retinal vein occlusion or retinal artery occlusion before the age of 50 years, the incidence of hyperhomocysteinemia, as observed in heterozygosity for homocystinuria, was studied by the performance of a standardized, oral methionine-loading test. In four of the 19 patients (21%), two with retinal artery occlusion and two with central retinal vein occlusion, the after-load peak levels of homocysteine exceeded the mean level, established in normal control subjects, by more than two standard deviations and were as well within the ranges established in obligate heterozygotes for homocystinuria. Because the frequency of heterozygosity for homocystinuria in the normal population is one in 70 (1.4%) at the most, we conclude that hyperhomocysteinemia predisposes to the development of premature retinal artery and retinal vein occlusion (P < .01; chi 2 test).

Adult↗
PubMedDate not supplied

[Retinal vein occlusions: diseases for the internist?].

Retinal vein occlusion is a relatively common disease, usually associated with the presence of diseases related to internal medicine. Central retinal vein occlusion is the most frequently-occurring and clinically relevant type. In addition to the well-known classic risk factors, new hemostasis-related ones have been investigated in patients affected by central retinal vein occlusion. While data concerning a number of parameters remain contradictory, high levels of type 1 plasminogen activator inhibitor (PAI-1) and lipoprotein(a) and hyper-homocystinemia appear to play a significant role in the pathogenesis of this disease. Although based on a limited number of studies, this new knowledge could eventually provide important indications regarding prognosis and therapeutic strategies.

Hemostasis↗
PubMed2001

Capillary blood flow in acute branch retinal vein occlusion.

PURPOSE: To study retinal capillary blood flow during the acute stage of induced branch retinal vein occlusion (BRVO) in the feline retina and the effect of systemic blood pressure during this event. METHODS: Known fractions of the animal blood cells were labeled by a fluorescent marker and tracked by an electro-optical device as they flowed within the retinal microcirculation. Branch retinal vein occlusion was induced by photocoagulation of a large vein at the optic disk rim. The findings were video recorded and analyzed by computerized image processing. RESULTS: Reversed capillary blood cell flow from the blocked vein was noted immediately following occlusion of the vein. Two patterns of reversed capillary flow were identified: one from the blocked vein to a terminal arteriole and the other from a blocked vein to another vein via a junction with a terminal arteriole. Increased systemic blood pressure decreased the reversed flow in both flow patterns. CONCLUSIONS: 1) Flow deviation to nearby retinal arterioles or veins (shunting) through the normal capillary system is an immediate hemodynamic event following acute BRVO. 2) The reversed capillary flow is affected by the systemic blood pressure.

Acute Disease↗
PubMed1990

Vitrectomy prevents retinal hypoxia in branch retinal vein occlusion.

Vitrectomy has been shown to halt diabetic retinal neovascularization, but the mechanism of this process is unknown. We propose that vitrectomy improves the oxygen supply to ischemic inner retina by way of fluid currents in the vitreous cavity. In order to test this hypothesis, we induced branch retinal vein occlusion in cats and measured preretinal oxygen tension before and after branch retinal vein occlusion in ten nonvitrectomized and five vitrectomized eyes. Branch retinal vein occlusion caused a significant decrease in preretinal oxygen tension in nonvitrectomized eyes, in which the oxygen tension fell from 20 +/- 7 to 6 +/- 5 mmHg (P = 0.001). Conversely, in vitrectomized eyes the oxygen tension was not significantly reduced after branch retinal vein occlusion. The data demonstrate that branch retinal vein occlusion causes retinal hypoxia in nonvitrectomized eyes, whereas after vitrectomy the hypoxic effect of branch retinal vein occlusion is reduced. The relief of retinal hypoxia that follows vitrectomy may be responsible for halting retinal neovascularization after vitrectomy in diabetic patients.

Animals↗
PubMed1994

Retinal vein occlusions: case reviews of USAF aviators.

Retinal vein occlusions are primarily a disease of the elderly, frequently with permanent visual abnormalities. However, both branch and central retinal vein occlusions occur rarely in young individuals. Reported here are a series of retinal vein occlusions in USAF aviators. Seven cases were identified from records of the USAF Armstrong Laboratory Aeromedical Consultation Service from 1976-91. Four cases of central retinal vein occlusions and three cases of branch occlusions are summarized. Initial visual acuity ranged from 20/15 to 20/400. All seven aviators recovered 20/15 vision and returned to flying status. Hyperlipidemia was found in four of the seven aviators, and hypertension was diagnosed in two aviators. Included is a discussion of current concepts in the natural history, associated systemic conditions, treatment options, and aeromedical implications of retinal vein occlusions.

Adult↗
PubMedDate not supplied

Visual field defects after radial optic neurotomy for central retinal vein occlusion.

PURPOSE: Surgical decompression of the vein in central retinal vein occlusion (CRVO) by radial optic neurotomy (RON) was recently proposed as being surgically feasible, safe, and beneficial. The effect of RON on the visual field has not been systematically reported, although possible visual field defects are expected due to iatrogenic cutting of the optic nerve fibers. The authors report the results of visual field testing in patients who underwent RON at the Tel Aviv Medical Center. METHODS: Twelve consecutive patients (8 men, mean age of all patients 68 years) with nonperfused or indeterminate CRVO whose initial visual acuity (VA) was < or =20/400 underwent RON. Nine of these patients were able to perform visual field tests at 6 months post-RON and their visual field results are presented. RESULTS: : VA improved by > or =3 lines in 5 patients (42%). Three (25%) patients had a final VA of > or =20/200 and another had a final VA > or =20/50. Fundus and VA improvement were relatively slow. Two patients had clearing of the intraretinal blood, resolution of the venous dilation, and improved VA at the 2-month follow-up visit. Temporal visual field defects consisting of temporal ones that could be correlated to the site of the RON incision were detected in five out of the nine patients who were able to perform visual field tests. No temporal visual field defects were found in the remaining four patients, and three other patients were unable to perform visual field tests due to inability to identify the largest target size. CONCLUSION: VA improvement in 5 of 12 patients with ischemic or indeterminate CRVO following RON may be better than the natural history of CRVO. The risk of visual field defects may, however, be heightened by possibly cutting off blood supply to the optic nerve head and possible damage to nerve fibers in the optic nerve head, both inherent to the surgical procedure and both likely to produce visual loss.

Adult↗
PubMedDate not supplied

Central retinal vein occlusion during remission of ulcerative colitis.

BACKGROUND: Retinal vascular disease is a rare complication of ulcerative colitis. CASE: We report a patient who developed unilateral nonischemic central retinal vein occlusion (CRVO) (papillophlebitis) without any other retinal vascular disease during remission of ulcerative colitis. OBSERVATIONS: The best-corrected visual acuities were 1.5 OD and 0.7 OS. Dilated and tortuous retinal veins and retinal bleeding were seen in the left eye. Macular edema and leakage from the papilla and the retinal veins of the left eye were evident on fluorescein angiography. After increased dosage of systemic prednisolone was prescribed, the retinal vascular changes resulting from CRVO (papillophlebitis) in the left eye gradually abated. CONCLUSIONS: Retinal vascular diseases should be monitored during both remission and activation of intestinal symptoms of ulcerative colitis.

Adult↗
PubMed1985

Underlying medical conditions in young patients and ethnic differences in retinal vein occlusion.

Eighty-seven patients with retinal vein occlusion were investigated for the prevalence of associated conditions, and divided in two groups, young (less than 50 years, n = 40) and an older group (greater than 50 years, n = 47). Young patients had a highly significant decreased prevalence of hypertension compared to the older group (27 per cent versus 62 per cent: P less than 0.001), with hyperlipidaemia being the predominant underlying condition (35 per cent). Four young female patients presenting with retinal vein occlusion were on the contraceptive pill. In the majority of young patients (60 per cent) an underlying medical condition could be identified. Striking ethnic differences in the occurrence of retinal vein occlusion have also been observed in a total of 214 patients referred without prior selection in two major ophthalmological centres over a four year period. Only 3 per cent of patients with retinal vein occlusion were Asian and 2 per cent of West Indian origin. In particular, no West Indian patient has been seen with the central form of venous occlusion. We conclude that hyperlipidaemia, and not hypertension, is the predominant associated medical condition in young patients and that other aetiological factors including the contraceptive pill may be found. Marked ethnic differences have also been observed which may give further insight into the exact aetiology of retinal vein occlusion.

Adult↗
PubMed1989

Diabetes as a risk factor for retinal neovascularization in retinal vein occlusion.

We evaluated a series of patients with retinal vein occlusive disease to determine whether diabetic patients with vein occlusions developed retinal neovascularization more frequently than did nondiabetics. Retinal neovascularization occurred in 68.8% of diabetics after central retinal vein occlusion compared with 27.8% of nondiabetics. Diabetics with branch retinal vein occlusions showed no greater likelihood for subsequent retinal neovascularization than did nondiabetics.

Diabetic Retinopathy↗
PubMed1996

Hyperbaric oxygen treatment for macular edema in retinal vein occlusion: relation to severity of retinal leakage.

Twelve subjects with macular edema in retinal vein occlusion received hyperbaric oxygen treatment. Median visual acuity improved from 20/100 to 20/25 (p = 0.002). Clinically significant improvement (2 lines or more) was achieved in 10 cases (83%). Evaluation of the inward permeability coefficient of the blood-retinal barrier using vitreous fluorophotometry showed no significant alteration in the permeability. Studies of larger groups of vein occlusion patients are required to better understand and characterize the visual changes after the oxygen treatment. Moreover, further follow-up is required before conclusions can be reached about the long-term effect of this treatment.

Aged↗
PubMed1995

[Bilateral central retinal vein occlusion and circulating anticoagulant].

A case of central retinal vein occlusion with second development of the same type of retinal vein occlusion in the fellow eye, is reported. The patient was a 68 year-old man with a history of thyroid gland disorder and a cardiac arrhythmia. He presented also with bilateral tilted disc. The first eye occlusion was initially nonischemic, but converted secondarily into an ischemic type and required laser panretinal photocoagulation. The biological assay found the presence of lupus anticoagulant antibodies and rheological findings (major plasma hyperviscosity, increased erythrocyte aggregation, high hematocrit and fibrinogen levels). The patient was given high doses of troxerutin, and aspirin. Central retinal vein occlusion occurred in the fellow eye one year later, a few weeks after the decrease of troxerutin doses. Hemodilution therapy was performed and visual acuity remained unchanged. Unusual risk factors for retinal vein occlusion are discussed. Lupus anticoagulant antibodies may sometimes lead to occlusive vascular phenomenon. Although these antibodies are not commonly found in retinal vascular occlusion, they may constitute a contributory factor. Tilted disc has often been involved in the pathogenesis of central retinal vein occlusion. Finally, abnormal rheological findings, major in this case, are found in more than half of the cases of retinal vein occlusion.

Aged↗