People with diabetes have a high risk of developing, over time, ocular diseases that can endanger the health of their eyes. This is due to the fact that, in diabetic individuals, the physiological mechanism that regulates blood glucose concentration (glycemia) is deficient or absent. For this reason, blood glucose levels tend to be often too high, especially if the patient does not follow an appropriate and rigorous dietary and pharmaceutical protocol, with harmful effects on the body and, in particular, on the integrity of the blood vessel walls, including those at the retinal level.
When diabetes begins to compromise the structure of the retinal blood vessels, the patient has a high probability of developing diabetic retinopathy, an ocular disease that can cause very serious damage to the retina and the optic nerve, and consequently to vision. There are two forms of diabetic retinopathy: non-proliferative diabetic retinopathy and proliferative diabetic retinopathy.
Non-proliferative diabetic retinopathy is caused by exudation of blood and fluids—often pinpoint or otherwise small in extent—from the blood vessels of the retina, a phenomenon often accompanied by the formation of exudates. Among the most serious complications of non-proliferative diabetic retinopathy are diabetic macular edema (DME) and macular ischemia, conditions that are very dangerous for vision.
Diabetic macular edema is characterized by swelling of the macula, the central area of the retina responsible for sharp and detailed vision. This ocular complication is of particular social relevance today, as it affects a high percentage of people with diabetes and is the leading cause of vision loss in the working-age population.
Macular ischemia occurs when one or more capillaries that bring blood to the macula become obstructed, causing ischemia in the macular tissue and sudden visual impairment, whose severity depends on the extent of the ischemia itself. This condition is particularly insidious as it often triggers a series of events that lead to the development of the proliferative form of diabetic retinopathy.
Proliferative diabetic retinopathy is characterized by pathological neovascularization caused by an insufficient supply of oxygen (hypoxia) to the retina or the optic nerve, due to occlusion of some retinal blood vessels. The retina responds to the hypoxic state by promoting the growth of new blood vessels, which however present a particularly fragile, pathological structure. This can lead, depending on the pathophysiological mechanism that is established, to various ocular complications, including vitreous hemorrhage, the formation of an epiretinal membrane (which in turn can lead to tractional retinal detachment, macular pucker, and macular hole) and neovascular glaucoma.
To diagnose diabetic retinopathy, specific tests are necessary such as optical coherence tomography (OCT) and fluorescein angiography (FAG). These tests allow the ophthalmologist to diagnose diabetic retinopathy before it causes damage to vision. For this reason, it is essential that patients with diabetes undergo regular eye exams, even if they have no symptoms.
Once diagnosed, diabetic retinopathy must be monitored through frequent retinal examinations using OCT and FAG. In this way, if necessary, the patient can undergo the most appropriate therapy, which—depending on the complication that has occurred—may consist of laser treatments, intravitreal injections of anti-VEGF drugs, implantation of slow-release intravitreal devices, or vitrectomy.
Today, thanks to advances in technique and medicine, the severe complications of diabetic retinopathy can be kept more under control. However, a definitive treatment does not yet exist, which is why the most effective and valuable weapon against this serious eye disease is prevention, which consists in strict blood sugar control and must be carefully planned through close collaboration among the ophthalmologist, general practitioner, diabetologist, and patient.
The risk of ocular complications in patients with diabetes increases with the duration of the disease. For this reason, in addition to prevention, diabetic patients must pay special attention to early diagnosis.
Early diagnosis is an irreplaceable weapon in combating the consequences of diabetic retinopathy. In fact, it has been shown that the risk of vision loss is significantly reduced if diabetic patients undergo regular and thorough retinal monitoring. People with type 1 diabetes should have a thorough eye exam within five years of their diabetes diagnosis, and then once a year; people with type 2 diabetes should instead have an eye exam immediately after diagnosis, and then at least once a year.
Macular edema is the main cause of vision loss in diabetic patients, but also the risk of cataract, even at a young age, and angle-closure glaucoma is higher in those suffering from diabetes.
Protecting eye health must be a priority for all diabetic patients, even more so for children, who have to live with the disease for many years, and for pregnant women, in whom this condition can progress very quickly, making a thorough eye exam necessary already during the first trimester of pregnancy.
It is of fundamental importance that this information reaches all diabetic patients, so that knowledge and awareness can help them manage their condition in the best possible way, safeguarding their vision and quality of life.
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