Retinal blood flow calculated using video fluorescein angiography after arteriovenous sheathotomy in eyes with branch retinal vein occlusion

Purpose: To study the effect of arteriovenous sheathotomy on retinal blood flow (RBF) in eyes with branch retinal vein occlusion (BRVO) using video fluorescein angiography (VFA). Methods: The results of VFA performed using the scanning laser ophthalmoscope were evaluated to determine RBF at the distal site of arteriovenous crossing causing BRVO preoperatively and 1 week postoperatively. A bolus of 0.8 ml of fluorescein dye was injected into the antecubital vein and mean circulation time (MCT) in the vessels was calculated by fitting the results of VFA to the dye dilution curves. Four eyes of 4 patients were examined. Results: Preoperative RBF in the affected vessels (18.3 ± 2.6 pixels²/second), which was lower than RBF in healthy nasal vessels (40.3 ± 14.1 pixels²/second), was significantly improved at 1 week after surgery (35.4 ± 6.3 pixels²/second) (p<0.05). Postoperative MCT (5.0 ± 0.8 seconds) was significantly shorter than the preoperative MCT (7.3 ± 0.7 seconds) (p<0.05). Conclusion: The results of our study demonstrated that retinal blood flow improves after sheathotomy in eyes with BRVO. The technique of evaluating VFA results by fitting them to dye dilution curves may be useful to study the effects of surgery on retinal circulation.