Diabetic retinopathy is a condition characterised by lesions affecting the retinal capillaries (non-proliferating form: micro-aneurysms, retinal and vitreous haemorrhages , ischemic areas - proliferating form: neovessels or neovascularisation). A very serious complication is the formation of macular edema.
This disease is the major ocular complication caused by diabetes mellitus.
In the early stages the disease can be asymptomatic, but as it progresses it can cause clouding and a progressive loss of vision, which can result in visual impairment and blindness.
First of all, proper integrated diabetes management through strict glycemic, lipids and blood pressure control is required.
Vascular lesions can be treated with laser photocoagulation. In severe cases vitrectomy surgery is performed. In recent years, intravitreal therapies with antiangiogenic drugs have been proposed.
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.
AMD (Age-related Macular Degeneration): degenerative chronic pathology, progressive and with tendency to become bilateral, affecting the macula, the central area of the retina providing distinct vision. It occurs in dry form (non-exudative AMD) and wet form (exudative AMD).
The causes of the disease are unknown. The pathogenesis is related to physiological ageing of the eye, in addition to a number of other risk factors: demographics (age, sex, ethnic factor), genetic and environmental (family history, smoking, alcohol consumption, diet rich in saturated fats and low in fish, fruits and vegetables, obesity, lack of physical activity, prolonged exposure to sunlight).
In early stages: altered perception and distorted images (lines appear wavy), sometimes opaque spots at the centre of the visual field. In advanced stages: progressive loss of vision, particularly of central vision.
For dry form it is suggested to take dietary supplements (vitamins, minerals, antioxidants, carotenoids, ω-3 fatty acids) formulated to slow down the progression of the disease.
In the wet form today there are several treatment options that include: laser photocoagulation, photodynamic therapy and antiangiogenic therapy with intravitreal administration of drugs that block the proliferation of new vessels.
AMD (Age-related Macular Degeneration) is a degenerative progressive chronic pathology with a tendency to become bilateral, affecting the macula, the central area of the retina responsible for distinct vision of image details.
There are two forms of AMD:
- the "dry" form, which covers about 90% of all macular degeneration characterised by the accumulation beneath the macula of yellowish material deposits, the drusen, which gradually alter the functionality of the photoreceptors, the cells responsible for light stimuli perception;
- the "wet" form, fortunately less frequent than dry AMD, but with more debilitating outcomes , characterised by the formation of abnormal blood vessels beneath the macula. These vessels, with very fragile walls, can easily allow liquid to exude, or they may break, causing haemorrhages in the retina.
Although the causes of the disease are not yet fully known, some risk factors have certainly been identified. First of all age (the risk of onset of this pathology increases with age), in addition to other risk factors: demographics (age, sex, ethnic factor), environmental and genetic (family history, smoking, alcohol consumption, diet rich in saturated fats and low in fish, fruits and vegetables, obesity, lack of physical activity, prolonged exposure to sunlight.
AMD initially manifests as a gradual reduction in visual acuity associated with altered and distorted perception of the images (lines appear wavy). More light may be needed to read and difficulty to recognise people, unless they are very close. Sometimes it occurs with opaque spots (scotomas) in the centre of the visual field, but often the symptoms are masked by the fact that the problem affects only one eye.
In the "dry" form the loss of central vision occurs slowly and gradually, and it is possible to see a black spot in the centre of the visual field. Whereas in the "wet" form, the loss of central vision is unfortunately very fast.
If any of the symptoms described appear, it is better to undergo an eye examination as soon as possible.
The ophthalmologist may diagnose AMD during the eye examination that includes among others: visual acuity test, ocular fundus examination in dilated pupil, examination of the optic papilla and the Amsler test. The latter is a grid similar to an exercise worksheet with a black dot in the centre that the ophthalmologist will ask you to look at, one eye at a time, staring at the central dot. The vision of wavy lines, spots, or the absence of some lines on the grid must be reported to the doctor.
If the ophthalmologist suspects AMD, additional tests may be required such as fluorescein angiography or indocyanine-green angiography angiography, which are useful to detect alterations in retinal circulation or choroid.
There are two more important non-invasive diagnostic tests:
- optical coherence tomography (OCT), which allows you to observe, without any contrast media, retinal sections in high definition;
- Microperimetry, which allows the evaluation of the visual sensitivity of each point of the macula.
For dry AMD (non-exudative) it is widely recognized the importance of using specially formulated dietary supplements to slow the progression of the disease, by the guidelines of the American Academy of Ophthalmology (A.A.O.), official agency of reference for the Ophthalmologists around the world.
Dietary supplements designed to slow AMD progression include:
- vitamin C and vitamin E, which act by slowing ageing processes and cellular degeneration caused by the production of free radicals.
- zinc, involved in many enzymatic activities, localised at retinal level.
- copper, an essential oligoelement for the activity of numerous enzymes, which always complements zinc intake.
- lutein and zeaxanthin, carotenoids that accumulate in the central part of the retina (the macula lutea), forming the macular pigment, an important eye protective shield.
- astaxanthin, the most powerful antioxidant present in nature provided also with anti-inflammatory and antiangiogenic properties.
- ω -3 fatty acids, called "essential" because they cannot be synthesised by the body, but must be taken as part of your diet. Major constituents of the outer membrane of photoreceptors, have anti-inflammatory and antiangiogenic activities.
Several preclinical and clinical studies have demonstrated the protective effects of all of these components against the risk of AMD progression.
For the treatment of wet AMD (exudative) today there are numerous therapeutic options, from traditional ones, such as laser photocoagulation and Photodynamic therapy (PDT) to the latest antiangiogenic drug therapy. Laser photocoagulation consists of using a laser beam of particular strength to destroy abnormal blood vessels developed in the retina. In some cases it is possible to use Photodynamic therapy (PDT), which selectively destroys abnormal blood vessels through the intravenous injection of a photosensitive pharmacological substance which is activated by laser treatment.
