Diabetic retinopathy is the main eye disease caused by diabetes mellitus: a syndrome in which blood sugar levels are elevated, since the body is unable to handle them properly.
High levels of sugar, over time, can damage blood vessels, especially affecting richly vascularized organs; these include the eye, in particular the retina, the structure responsible for transforming light into images.
The diabetologist will frame the complications of diabetes throughout the body, while the ophthalmologist will focus on the ocular complications, such as diabetic retinopathy.
BUT HOW DOES DIABETES DAMAGE YOUR EYES?
The most common cause of visual loss in people with diabetic retinopathy is macular edema: a condition in which some liquids accumulate in the central and most noble part of the retina, the macula, responsible for detailed vision; in addition, the so-called neovascularization can occur, a phenomenon in which abnormal and fragile blood vessels can grow on the surface of the retina.
A neovascularization can significantly expand, contract and pull on the retina; all this can lead to bleeding, a phenomenon known as “vitreous hemorrhage” and other complications such as retinal detachment.
WHAT ARE THE SYMPTOMS OF DIABETIC RETINOPATHY?
The symptomatology of diabetic retinopathy differs greatly from subject to subject and can vary from the gradual clouding of vision to a sudden and severe visual loss; however, it should be stressed that the patient with diabetic retinopathy may also have no symptoms, up to advanced stages of the disease; it is therefore very important that an eye examination is performed with dilation of the pupils at least once a year; care must also be taken not to confuse the figure of the ophthalmologist, a graduate in medicine and surgery and specialized in ophthalmology, with other professional figures such as the optician or orthoptist.
The greatest risk is that of not recognizing the disease promptly; sudden changes in vision and the sensation of seeing moving bodies in those with diabetes mellitus must be promptly brought to the attention of the specialist.
HOW LONG CAN DIABETES DAMAGE THE EYES?
The longer the duration of diabetic disease and the greater the decompensation, i.e. poor blood glucose control, the greater the possibility of developing retinopathy.
After 25 years, almost all people with diabetes mellitus can show signs, even mild ones, of diabetic retinopathy.
The diagnostic process involves:
– Dialogue with the patient to identify risk factors
– Comprehensive examination of the eye to highlight signs that may advance the suspicion of diabetic retinopathy; the so-called “eye fundus examination” is also included in the overall eye examination, through which the ophthalmologist can identify some characteristic signs of the disease.
– Instrumental tests such as retinography, or a photo of the retina, OCT (non-invasive examination and useful for documenting the response of macular edema to therapy) and fluorescein angiography: necessary to determine the peripheral extension of diabetic retinopathy or to identify fluid loss or bleeding points.
The examination is carried out by injecting a dye, fluorescein sodium, into a vein in the arm, which will reach the retina after a few seconds; at this point, photographs will be taken at well defined times, to dynamically follow the alteration of the blood flow, characteristic of retinopathy.
Fluorescein angiography is considered an important and safe examination in a hospital setting or with the presence of an anesthesiologist.
One of the most common side effects is the yellowish appearance of the skin and the orange color of the urine for a few hours; most people have no difficulty in undergoing such an examination, even if a small percentage of patients may experience transient nausea after the injection and more rarely allergic reactions can occur, even serious ones and for this reason, if there are known allergies to drugs or food, the patient is always required to notify the doctor, who will thus take care of any precautions.
Another instrumental examination that could be useful in the diagnostic process of diabetic retinopathy is ocular ultrasound: it is useful when the retina cannot be directly visualized with a standard examination due to the opacity of the various ocular structures; this happens, for example, in the case of virtual bleeding or advanced cataract; ultrasound is necessary to identify any retinal breaks, tractions or detachments.
HOW IS DIABETIC RETINOPATHY TREATED?
The first thing the patient must do is to keep his blood sugar under control, scrupulously following the advice that the diabetologist will have provided.
Laser photocoagulation is considered the standard treatment of diabetic retinopathy; a laser beam emits, in fractions of a second, a very intense energy that will close abnormal vessels or gently burn areas of the retina that are now considered too damaged and that cause problems in healthy areas.
Numerous clinical studies have shown that laser photocoagulation reduces the risk of severe visual loss in people with diabetic retinopathy; in general, laser treatments are necessary to stabilize or prevent the progression of complications related to diabetic retinopathy, and it is also possible to induce an improvement in vision.
The best results are obtained when the problems related to diabetic retinopathy are treated immediately. The treatment can include several sessions.
Intravitreal injections consist of the introduction, by injection, of specific drugs into the eye, precisely in its gelatinous component known as the vitreous body.
These drugs aim to allow the reabsorption of macular edema and to counteract the growth of abnormal vessels; also in this case it may be necessary to repeat the injections several times to control the disease over time.
Surgery may be required in some patients with diabetic retinopathy; this happens when there is massive bleeding inside the eye or traction on the retina which can cause loss of vision.
The surgical procedure, called vitrectomy, involves the removal of the vitreous body full of blood and the tissue that exerts traction on the retina; all this is done with small instruments that are inserted by the surgeon inside the eye, all with the aid of a microscope.
Instead of the removed vitreous body, other fluids, gas or silicone oil are introduced, to keep the retina in its position; contextually an intraoperative laser photocoagulation can be performed.
The prognosis of subjects requiring vitrectomy depends on the degree of advancement of the diabetic retinopathy.
Remember: if you are a diabetic subject, an eye examination is very important, so that your eye doctor can identify and eventually treat the first ocular manifestations of the disease immediately.