Abstract
Purpose: :
Retinal venous occlusion is a common ophthalmic problem with significant visual morbidity. There is no current standard treatment in the acute setting and no medical or ocular intervention can reverse the occlusion once it has occurred. There are a number of reports on the use of haemodilution in retinal vein occlusions to increase blood flow through the occluded segment.
The objective of this study was to systematically review the effect of haemodilution treatment on visual function in retinal vein occlusion.
Methods: :
A literature search for retinal venous occlusion and haemodilution was undertaken on the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE. All randomised controlled trials with central or branch retinal vein occlusions where included. We excluded studies where only a combination of haemodilution and other rheological or pharmacological agents are used. The primary outcome measure was an improvement in visual acuity of three LogMAR lines or more (equivalent to doubling of the visual angle) at 3, 6, and 12 months.
Results: :
611 references were reviewed and 13 possible papers identified. 7 studies met our inclusion criteria and 6 had data that could be used for meta–analysis. Of these two used hydroxyethylene starch and three used dextran as plasma expanders. One study used normal saline for haemodilution. Meta–analysis of these studies provided evidence that haemodilution improves visual outcome following retinal vein occlusion. The odds ratio for treatment of central retinal vein occlusions was 0.31 (95% CI, 0.15–0.65) and 0.18 (95% CI, 0.06–0.54) at 3 and 12 months respectively. The odds ratio for treatment of branch retinal vein occlusions was 0.23 (95% CI, 0.07– 0.80) and 0.18 (95% CI, 0.05–0.65) at 3 and 12 months respectively. One study (using saline for haemodilution) displayed a degree of heterogeneity. Analysis performed with or without this study did not significantly change our results.
Conclusions: :
Meta–analysis showed the benefit of haemodilution treatment for retinal vein occlusions. Treatment is associated with an increased chance of visual improvement. The studies reviewed are small and larger studies using a standard regime with a colloid plasma expander for haemodilution are warranted.
Keywords: vascular occlusion/vascular occlusive disease • retina • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials