Stellate ganglion block increases blood flow into the optic nerve head and the peripapillary retina in human

The effects of stellate ganglion block (SGB) on the blood flow of the optic nerve head (ONH) and the peripapillary retina, which plays an important role in the pathogenesis of a major blinding disease, e.g. glaucoma, are unclear. The aim of this study was to evaluate the effects of a sympathetic block on the blood flow of the ONH and the peripapillary retina. Heidelberg Retinal Flowmetry, which is a system incorporating a noninvasive confocal scanning laser Doppler flow meter, was used to measure the retinal blood flow. A unilateral stellate ganglion block was performed in 11 healthy subjects. The retinal blood flows were measured before, 30 and 120 min after SGB. On each occasion, three scans were obtained and the blood flow was analyzed. The systemic blood pressure (BP) and the intraocular pressure (IOP) were also measured at the set time points. The blood flow of the ONH and the peripapillary retina of the ipsilateral retina was significantly increased (P=0.001) by 106.8% and 98.7%, respectively, 30 min after SGB without accompanying significant changes in BP and IOP when compared to their baseline values; while those of the contralateral eyes did not change. The effect of SGB on blood flow in these areas disappeared 120 min after SGB. In conclusion, SGB may have a beneficial effect on ocular diseases associated with ischemia of the ONH and the peripapillary retina, e.g. glaucoma.