It is known that NO is involved in the regulation of intraocular pressure (IOP) and retinal function recovery after ischemia. Thus, S-nitrosoglutathione (RVC-588) and 4-phenyl-3-furoxancarbonitrile (RVC-589) as NO donor and precursor, respectively, were studied in terms of their ability to increase b-wave recovery of electroretinogram (ERG) and ocular blood flow. It was found that RVC-588 increased b-wave amplitude markedly from 28% (control) to 67% (treated) and the blood flow significantly in the retina, choroid, and ciliary body. In the case of RVC-589, the b-wave recovery was significantly increased from 30% (control) to 51% (treated) but was less marked than that of RVC-588. The blood flow in the eye tissues was not significantly increased by RVC-588, but there was a clear tendency to enhance in the retina, choroid and iris. These results indicate that NO can be released effectively from S-nitrosothiols but less significantly from furoxans.