Diabetic retinopathy is a condition characterised by lesions affecting the retinal capillaries in patients suffering from both insulin dependent or independent diabetes mellitus. Generally there are no signs until 5 years after diagnosis. According to the type and degree of lesions two forms of diabetic retinopathy can be distinguished: a non-proliferating diabetic retinopathy and a proliferating diabetic retinopathy.
Non-proliferative diabetic retinopathy is characterised in its initial phase by the presence of micro-aneurysms, micro-haemorrhages and then of exudates. A complication of this form of diabetic retinopathy is macular edema that can severely impair central vision. Proliferative diabetic retinopathy is characterised instead by the development of new blood vessels (neovascularisation), which are extremely fragile and can exude liquid or break causing severe haemorrhages.
Diabetic retinopathy is the major ocular complication caused by diabetes mellitus and in industrialised countries is the leading cause of legal blindness among working-aged people. The symptoms related to it often appear belatedly, when lesions are already advanced, and this often restricts the effectiveness of the treatment. The main risk factors associated with earlier signs and a more rapid progression of retinopathy are the duration of diabetes, glycemic decompensation and possible arterial hypertension.
IIn the early stages, diabetic retinopathy is usually asymptomatic. As the pathology progresses there are symptoms that vary depending on the extent and location of the lesions. Diabetic retinopathy usually affects first peripheral areas of the retina, but when the macula is affected, even in early stages, clouding and a sharp reduction of the vision acuity due to the appearance of a macular edema could happen. Sudden vision loss can be caused by an intraocular haemorrhage (vitreous haemorrhage) or a large vessel occlusion (thrombosis).
Blindness from diabetic retinopathy may be avoided in more than half of the cases if proper patient information and appropriate forms of health education were implemented, which are critical to the success of any policy of prevention of visual impairment in diabetes (population screening, national computerised register of diabetic patients, etc.). An ocular fundus examination once a year and when necessary a fluorescein angiography are now an established practice in the management of all diabetics. The fluorescein angiography in particular highlights the early injury of retinal capillaries and assesses the need for laser treatment.
Diabetic retinopathy treatment starts with a strict control of blood sugar levels and blood pressure as well as any other metabolic disorders that are present, such as hypercholesterolemia. In initial forms capillary-protective drugs to increase vascular resistance are often used. In more serious cases instead, laser photocoagulation is used to stabilise the disease through the destruction of the lesions and prevention of haemorrhaging. Also, when haemorrhages occur in the vitreous body, growth of abnormal capillaries and fibrous adhesions that raise and detach the retina, vitrectomy surgery may be a solution, which involves the removal of the vitreous body and replacing it with transparent liquids (silicone oil or saline solution). The cutting edge for drug treatment of diabetic retinopathy refers to the use of antiangiogenic substances which, injected directly into the vitreous humour, block the proliferation of new vessels.
In more advanced stages of retinopathy, it is possible to reduce the discomfort due to low vision, using optical systems for the visual impaired. Given the human, social and economic costs resulting from diabetic retinopathy, patients and their family doctors should be properly informed about the possibility of rehabilitation and how to get it.
SIFI proposes a range of nutritional supplements formulated specifically to ensure adequate dietary intake to maintain the health of the retina.