The review article focuses on free radicals and oxidative stress involved in ophthalmological diseases such as retinopathy, cataract, glaucoma, etc. Oxidative stress is considered as a key factor involved in the pathology of many chronic diseases including ophthalmic complication and inflammatory process. Oxidative stress and inflammation are closely related pathophysiological processes and are simultaneously found in many pathological conditions. The free radicals produced oxidize cellular components such as lipids and phospholipids leading to lipid peroxidation and trigger the onset of retinopathy. Cataract is a significant cause of visual disability and it is proposed that the high incidence is related to oxidative stress induced by continued intraocular penetration of light and consequent photochemical generation of free radical oxidants. Glaucoma is the leading cause of irreversible blindness and comprises a group of diseases characterized by progressive optic nerve degeneration. Oxidative injury and altered antioxidant defense mechanisms in glaucoma appear to play a role in the pathophysiology of glaucomatous neurodegeneration that is characterized by death of retinal ganglion cells. The UVB radiations through this way may cause a number of diseases like photo-keratitis, pterygium, damage to epithelium, edema, and corneal cell apoptosis.: ROS: reactive oxygen species; RNS: reactive nitrogen species; O: superoxide anion; HO: hydrogen peroxide;. OH: hydroxyl radicals; ONOO, ONO peroxynitrite; NO: nitric oxide; IOP: intraocular pressure; RGC: retinal ganglion cells. WHO: World Health Organization; IAPB: International Agency for the Prevention of Blindness.