Remarkable advances have been made recently in the field of ocular pharmacology. They include pharmacological treatments of glaucoma, uveitis, myopia, ischemic retinopathy, age-related macular degeneration (AMD), dry eye syndroms, cataract and wound healing. It is known that nitric oxide (NO) produced by constitutional NO synthase (eNOS, bNOS) could be beneficial to lower the intraocular pressure and to improve ocular blood flow in glaucoma; to relax ciliary muscle to shorten the axis in myopia; to facilitate retinal and choroidal blood flow in ischemic retinopathy and AMD; to imporve tear formation and tear protein secretion in dry eye syndrome. On the other hand, inhibition of inducible NOS (iNOS) to over produce NO might be useful to protect optic nerve and retinal nerve degeneration in glaucoma; to prevent inflammatory repsones in uveitis; to avoid apoptosis of posterior sclear lesion in myopia; to prevent acinar cell degeneration in dry eye syndrome; to reduce polymerizaion of lens crystal proteins by free radicals in catarct; an to adjust the processes in wound healing. In short, most eye diseases could be related to under-production or over-production of NO in eye tissues. Manipulation of NO levels could become the new way for the treatment/prevention of various eye diseases.