Purpose: The effect of stellate ganglion block (SGB) on human retinal blood flow was evaluated.
Methods: We measured the diameter of the retinal artery and vein, and retinal venous flow rate by laser speckle retinal blood flow meter simultaneously in 11 eyes of 11 normal volunteers.
Results: The reliable data from 9 eyes of 9 person were used for analysis. SGB did not change the blood pressure, heart rate, retinal arterial diameter, or venous diameter. However SGB increased retinal blood velocity significantly from 9.9 +/- 1.6 (mean +/- standard deviation) mm/s to 11.1 +/- 1.5 mm/s (p < 0.01). Intraocular pressure decreased from 12.3 +/- 2.1 (mean +/- standard deviation)mmHg to 9.4 +/- 2.2 mmHg after SGB (p < 0.01). There was no relationship between the change of ocular perfusion pressure and that of retinal venous blood velocity.
Conclusion: SGB increased the retinal venous blood velocity without changing the retinal vessel diameter.