Abstract: In  recent years it has been recognized that nitric oxide(NO) is a hot spot in research of ocular diseases. As a molecular medium synthesized by nitric oxide synthase (NOS). NO is involved in the control of ocular blood flow. Abnormalities of NO system have been observed in a variety of ocular diseases including uveitis, glaucoma, retinal ischemic diseases, diabetic retinopathy and retinitis pigmentosa. In addition, its antagonist endothelin1(ET1) also attracts much attention. All these make the nitric oxide pathway an attractive target for therapeutic interventions of ocular diseases.   (Int Rev Ophthalmol, 2014, 38:   420-424)