Arterial blood flow characteristics in central retinal vein occlusion and effects of panretinal photocoagulation treatment: an investigation by colour Doppler imaging.
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AIMS: To determine whether an increase in vascular resistance in the central retinal and ophthalmic arterial circulations contributes to the development of central retinal vein occlusion (CRVO), or haemodynamic alterations in central retinal and ophthalmic arteries occur secondary to the vein occlusion as increased intravascular pressure is transferred through the capillary bed to the arterial side and the effect of panretinal photocoagulation treatment on these circulations in ischaemic cases. METHODS: The ophthalmic and central retinal arteries of the affected and non-affected eyes of 20 patients with non-ischaemic CRVO, 13 patients with ischaemic CRVO, and 22 control subjects were investigated by colour Doppler imaging. Panretinal photocoagulation (PRP) treatment was applied to the eyes with ischaemic CRVO. Maximum and minimum blood flow velocities, and resistivity indexes were calculated in the affected and healthy eyes of patients and in the control eyes. RESULTS: Average blood flow velocity in the central retinal and ophthalmic arteries of patients with non-ischaemic CRVO did not differ from their fellow eyes, but a significantly lower average blood flow velocity was found in the ophthalmic and central retinal arteries of the patients with ischaemic CRVO compared with their fellow eyes. Patients with ischaemic CRVO had significantly lower blood flow velocities in their ophthalmic and central retinal arteries than non-ischaemic cases that were further reduced following PRP treatment. CONCLUSION: This study suggests that impaired arterial blood flow observed in patients with CRVO may be partly related to secondary changes in the retrobulbar arterial circulation as a result of enhanced arterial resistance following CRVO. These data also demonstrate that PRP treatment decreases retinal and ophthalmic blood flow velocities in patients with ischaemic CRVO. (+info)
Blurred vision and high blood pressure in a young woman.
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A 41-year-old woman presented with a short history of blurred vision. She had a 6-year history of refractory hypertension which had been treated with a variety of drug regimens. She was found to have bilateral branch retinal vein occlusion. Retinal vein occlusion is a recognised complication of hypertension but simultaneous involvement of both eyes is extremely rare. Following this episode, blood pressure control has improved without change in drug therapy, suggesting that treatment compliance may partly explain the previous difficulties. (+info)
Increased interleukin-6 in aqueous humor of neovascular glaucoma.
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PURPOSE: To demonstrate the involvement of proinflammatory cytokines in intraocular neovascularization by detecting the presence of interleukin (IL)-6, IL-2, and tumor necrosis factor (TNF)-alpha in aqueous humor and serum of patients with neovascular glaucoma (NVG) secondary to central retinal vein occlusion (CRVO). METHODS: According to the grade of iris neovascularization (NVI), patients with CRVO were divided into three groups: CRVO without NVI, CRVO with NVI, and CRVO with regressed NVI. Healthy patients with cataract were enrolled as control subjects. Enzyme-linked immunosorbent assay was used to quantitate the concentrations of the cytokines IL-6, IL-2, and TNF-alpha in aqueous humor and serum from patients with NVG and control subjects. RESULTS: In serum, the levels of IL-6, IL-2, and TNF-alpha did not differ among groups. In aqueous humor, only IL-6 showed significant change among groups. IL-6 levels in aqueous humor of group 2, CRVO with NVI (1532.0+/-221.1 pg/ml; P < 0.001), and group 3, CRVO with regressed NVI (234+/-154.6 pg/ml; P < 0.001), were significantly higher. There was no significant difference in IL-6 levels between the control group (26.4+/-21.8 pg/ml) and group 1 (15.6+/-0.9 pg/ml). CONCLUSIONS: The inflammatory cytokine IL-6 in aqueous humor increased spatially and temporally correlated with the grade of NVI in patients of NVG secondary to CRVO. The aqueous IL-6 increased in NVI and decreased after vessels regressed. It is possible that the significantly higher level of IL-6 was due to intraocular synthesis because of the minimal change in serum. The increased level of IL-6 may have a putative role along with other angiogenic factors in angiogenesis of NVG as a possible predictor of NVI. (+info)
Raised plasma homocysteine as a risk factor for retinal vascular occlusive disease.
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BACKGROUND/AIMS: A moderately elevated plasma concentration of the sulphur amino acid homocysteine is an independent risk factor for atherosclerotic vascular disease. Many of the risk factors associated with coronary, cerebral, and peripheral atherosclerotic vascular disease are common to retinal vascular occlusive disease but it is unclear whether elevated plasma concentrations of homocysteine are also associated with such disease. This study assessed the relation between retinal vascular occlusive disease and elevated levels of plasma total homocysteine (tHcy). METHODS: A retrospective case-control study involving hospital based controls and cases with retinal artery, central retinal vein (including hemiretinal vein), and branch retinal vein occlusions was performed. The relation between elevated tHcy, defined as a level greater than or equal to 12 micromol/l and risk of retinal vascular occlusive disease was examined. RESULTS: 87 cases of retinal vascular occlusive disease including 26 cases of retinal artery occlusion, 40 cases with central retinal vein occlusion, and 21 cases of branch retinal vein occlusion were compared with 87 age matched controls. Mean tHcy levels were higher in all disease groups and this difference was significant in patients with retinal artery occlusions (p= 0.032) and patients with central retinal vein occlusion (p=0.0001). When adjusted for known cardiovascular risk factors, tHcy was an independent risk factor for retinal vascular occlusive disease (OR 2.85 (95% CI 1.43-5.68)). CONCLUSIONS: Elevated tHcy is an independent risk factor for retinal vascular occlusive disease. Assessment of tHcy may be important in the investigation and management of patients with retinal vascular occlusive disease. (+info)
Laser treatment and the mechanism of edema reduction in branch retinal vein occlusion.
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PURPOSE: To test a hypothesis on the physiological mechanism of the disappearance of macular edema after laser treatment. The hypothesis is based on the effect grid laser treatment has on retinal oxygenation and hemodynamics. It predicts that laser-induced reduction of macular edema is associated with shortening and narrowing of retinal vessels in patients with branch retinal vein occlusion (BRVO). METHODS: The study included 12 subjects, treated with argon laser photocoagulation for BRVO and macular edema. Fundus photographs taken at the time of diagnosis and again after laser treatment, were digitized, and diameter and segment length of retinal vessels was measured using NIH-Image program. RESULTS: Macular edema disappeared or was dramatically reduced in all cases after laser treatment. The diameter of occluded venules constricted to 0.81+/-0.02 (mean +/- SD, P = 0.019) of the prelaser diameter and adjacent arterioles constricted to 0.78+/-0.01 (P = 0.008). The laser treatment also led to shortening of the affected vessels. The final segment length of the occluded venules was 0.95+/-0.17 (P = 0.005) of the length before treatment. The corresponding value for the adjacent arterioles is 0.95+/-0.14 (P = 0.008). Control arterioles and venules in the same fundus did not change in either length or width. CONCLUSIONS: These results do not reject the authors' hypothesis that the disappearance of macular edema in BRVO can be explained by the effect the laser photocoagulation has on retinal oxygenation. Increased oxygenation causes vessel constriction and shortening and lower intravascular pressure, which reduces edema formation according to Starling's law. (+info)
Experimental preretinal neovascularization by laser-induced thrombosis in albino rats.
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The primary objective of this study was to develop a simple experimental model of angiogenesis by photodynamic thrombosis of the retinal veins in Sprague-Dawley rats. After a tail vein injection of rose bengal (40 mg/kg), all major retinal veins adjacent to the optic nerve head were photocoagulated with an argon green laser. The eyes were examined regularly for the following eight weeks. A grading system was devised using fluorescein angiograms and ADPase staining to describe the progression of the new vessels. Nine out of ten eyes showed development of the preretinal new vessels by day 14. Seven weeks after laser coagulation, 2 of 5 eyes developed localized tractional retinal detachment. Regression of the neovascularization was not noted in any of the animals during the follow-up period. The authors were able to establish an experimental model for preretinal neovascularization by vein occlusion. This model may be applied in study of the pathogenesis and treatment of retinal neovascularization. (+info)
Central retinal vein occlusion combined with cilioretinal artery occlusion.
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A healthy 65-year-old man with sudden profound visual loss in his right eye presented with clinical signs of central retinal venous occlusion and retinal whitening, indicative of a cilioretinal arterial obstruction. He had been diagnosed with cilioretinal artery occlusion at a private ophthalmology clinic three days before being referred to our department. On fluorescein angiogram of the affected eye, the proximal portion of the retinal arteries filled with dye 27.3 seconds after injection, indicating a delay in retinal arterial filling. Moreover, the cilioretinal artery did not fill at that phase, but went on to fill 45.1 seconds after injection. Over 63.4 seconds after the filling of the retinal arteries, the laminar flow of the retinal venous vessels appeared. This was not until 90.7 seconds after injection. This patient was elderly, had no systemic diseases, and showed non-ischemic CRVO, prolonged retinal arterial filling on fluorescein angiography, and poor prognosis in visual acuity. His clinical course seemed to favor the pathogenetic hypothesis of a primary arterial affection. (+info)
Treatment of recent onset central retinal vein occlusion with intravitreal tissue plasminogen activator: a pilot study.
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AIMS: To study the effects of intravitreal tissue plasminogen activator (tPA) in recent onset central retinal vein occlusion (CRVO). METHODS: 15 patients with recent onset CRVO (from 1-21 days' duration, mean 8 days) were given 75-100 microg of tPA intravitreally associate with low dose low molecular weight heparin. CRVO was perfused in nine patients and with mild ischaemia not exceeding 100 disc diameters in six patients. Follow up ranged from 5 to 21 months for 14 patients (mean 8 months). Visual acuity measurement, macular threshold (Humphrey perimeter), fluorescein angiography with the scanning laser ophthalmoscope with special emphasis on retinal circulation times, and retinal perfusion were performed at days 0, 1, and 8 and months 1, 3, and 6. RESULTS: Visual acuity was significantly improved on the first day after treatment in only one eye, and decreased transiently in six eyes (40%). Retinal blood velocity was not significantly modified by tPA injection. Retinal ischaemia developed in six eyes (43%), leading to panretinal photocoagulation in five eyes including one with rubeosis iridis. At the end of follow up, visual acuity had improved to 20/30 or better in five eyes (36%), including two with complete recovery; visual acuity was worse than 20/200 in three eyes (28%). No complication of tPA injection was observed. CONCLUSION: Intravitreal tPA treatment for CRVO appears to be simple and safe, but did not significantly modify the course of the occlusion in our patients immediately after treatment. Final visual outcome did not differ significantly from that observed in the natural course of the disease, but final visual acuity seemed to be slightly better. A randomised study is required to determine if intravitreal tPA actually improves visual outcome in CRVO. (+info)