Improvement of Retinal Blood Flow Volume Measured Intraoperatively by Laser Speckle Flowgraphy after Sheathotomy for Branch Retinal Vein Occlusion

Abstract

Purpose: : To evaluate whether the restored blood flow in the occluded retinal vein after arteriovenous sheathotomy for branch retinal vein occlusion (BRVO) can directly improve the intraoperative blood flow volume, as measured by Laser Speckle Flowgraphy (LSFG).

Methods: : Our group recently suggested that LSFG may be a useful modality for quantitatively and non-invasively assessing the increase in the blood flow volume of the retinal vein 7 days after arteriovenous sheathotomy for BRVO (2008 ARVO meeting). Ten eyes of 10 BRVO patients treated with vitrectomy were analyzed. Blood flow was restored during arteriovenous sheathotomy in 6 eyes of 6 patients. No restoration of blood flow was found in the occluded veins in 4 eyes of 4 patients. The relative blood flow volume was expressed as the mean blur rate (MBR), as measured by LSFG immediately before and after the arteriovenous sheathotomy, with the patient in a supine position. The focus of measurement was the blood flow volume through the retinal vein proximal to the arteriovenous crossing site.

Results: : In the 6 eyes with restored blood flow, the MBR after the arteriovenous sheathotomy increased by 28.1±17.4% compared to the MBR before the sheathotomy. In the 4 eyes without any observable restoration of blood flow, the MBR after arteriovenous sheathotomy increased by 0±5.4% compared to that before the sheathotomy. This difference was significant (P=0.015, student’s t-test).

Conclusions: : These results suggest that a restoration of blood flow in the occluded retinal vein after arteriovenous sheathotomy in BRVO eyes can improve the blood flow volume during surgery. A restoration of blood flow during surgery may be a suitable endpoint for arteriovenous sheathotomy for BRVO as a surgical procedure.

Keywords: vitreoretinal surgery • retina • vitreous