AIM: The effects of ZX-5, as nitric oxide (NO) donor, on ocular blood flow has been investigated using colored microsphere technique in previous study. The relationship between the production of NO by ZX-5 and ocular blood flow has been evaluated. ZX-5 has been shown to have strong positive effect on increasing choroidal blood flow. However, the effect of ZX-5 on retinal function recovery, the effects of its optical isomers, (R, R)-ZX-5 and (S, S)-ZX-5, on choroidal blood flow and retinal function recovery have not been studied and merit investigation. · METHODS: Colored microsphere technique was used for in vivo experiments to determine choroidal blood flow of ocular hypertension (40mmHg) in rabbit eyes. Electroretinography was used to measure the b-wave recovery as an indication of retinal function recovery. · RESULTS: (R, R)-ZX-5 increased choroidal blood flow at 10g/L, 50μL instillation into eyes at all time points (P <0.05). (S, S)-ZX-5 was not effective in increasing choroidal blood flow. ZX-5 and (R, R)-ZX-5 showed significant effects in retinal function recovery after ischemia of the retina at all time points (P <0.05); whereas (S, S)-ZX-5 did not show significant effect on recovery of b-wave after ischemia at most time points except at 120 and 240 minutes. · CONCLUSION: ZX-5 and (R, R)-ZX-5 have high potency in increasing the choroidal blood flow and improving the retinal function recovery. It is hoped that they could be used for the prevention/treatment of ocular blood flow related eye diseases.