Pathophysiology and hemodynamics of branch retinal vein occlusion☆
Presented in part at the Second International Symposium on Macular Edema, Lausanne, Switzerland, April 1998.
Received 29 June 1998; accepted 27 July 1999.
Abstract
Purpose
To describe the pathophysiologic and the hemodynamic changes associated with branch retinal vein occlusion (BRVO) on the basis of selected angiographic observations from a cohort of patients with BRVO and related anomalies of retinal blood flow.
Design
Retrospective, observational case series.
Participants
A total of 250 patients with incipient or manifest BRVO and 5 patients with related anomalies.
Methods
Color and red-free gray-scale fundus photography and intravenous fluorescein angiography.
Main outcome measures
Morphologic signs of disturbed retinal blood flow.
Results
All occlusions occurred at arteriovenous crossing sites where the artery is positioned anterior to the vein. Presumptive precursor abnormalities of blood flow at arteriovenous crossings include turbulence and upstream venous dilation. After the onset of BRVO, the clinical course is determined by the location of the BRVO in relation to the fovea, the extent of the involved venous drainage area, and the collateral drainage capacity from the area with compromised venous drainage to the adjacent areas of intact venous drainage. Collateral maturation occurs over a period of 6 to 24 months after the onset of BRVO, when a transient retinal edema may be seen that has a preponderance for foveal involvement because the perifoveal area has the highest density of preformed collaterals between adjacent venous drainage areas.
Conclusions
The treatment of BRVO may possibly benefit from a refined angiographic analysis of the process of collateral formation and new treatment methods aimed at accelerating the process of collateral maturation.
Manuscript no. 98339.
aDepartment of Ophthalmology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
Reprint requests to Nynne L. B. Christoffersen, MD, Department of Ophthalmology, Herlev Hospital, Herlev Ringvej 75, DK-2730 Herlev, Denmark
☆ Supported by grants from the Simon Spies Foundation, Copenhagen, and the Danish Association for Prevention of Blindness and Eye Disease (Værn om Synet), Copenhagen, Denmark.
ABSTRACT