Laser photocoagulation has changed the visual prognosis of diabetic patients affected by retinopathy. It aims to lower the risk of blindness of diabetic patients. The goal of photocoagulation is to reduce the tissue damage of microangiopathic origin expressed by nonperfusion areas and permeability abnormalities that are responsible for retinal ischemia and oedema respectively. Loss of visual acuity in the diabetic is due mainly to two causes : first, vitreous hemorrhage with its dramatic loss of vision; secondly, macular cystoid oedema, occuring more commonly and with progressive loss of central vision. The efficiency of pan-retinal photocoagulation in reducing the risk of vitreous hemorrhage and consequent blindness in patients with disc or preretinal newly formed vessels, has been ascertained by American and British randomised studies. The indications, technics and results of photocoagulation in non-proliferative diabetic retinopathy are the subject of many studies. Only photocoagulation for macular oedema due to intra-retinal microvascular abnormality has shown to be of benefit.