[Changes in retinal blood flow volume in experimental retinal vein compression]

The authors quantitated the retinal blood flow volume during and immediately after experimental compression of the temporal retinal vein in 5 Macaca fuscata monkey eyes. The hydrogen clearance method was used to quantitate the retinal blood flow volume. After placing a microelectrode on the retinal surface, we measured the blood flow volume 4 times at a 15-minute interval. This value served as a baseline for the experiments. Next we compressed the temporal retinal vein near the disc with a 25-gauge needle with a rounded tip under guidance by an indirect ophthalmoscope. We measured the blood flow volume during compression. The compression was maintained for 3 minutes. Further blood flow determination was performed 7 minutes after release of compression and was repeated 4 times at a 15-minute interval. During compression of the temporal retinal vein, the retinal blood flow volume in the area served by the vein decreased by an average of 35%. The flow volume recovered rapidly and remained stable after release of compression. There was no reactive hyperemia. This model appears useful to elucidate the retinal circulation of branch retinal vein occlusion.