What is Diabetic Retinopathy?
Diabetic retinopathy is a complication of diabetes mellitus (a metabolic disease characterized by high blood glucose levels) and one of the leading causes of blindness in Western countries. It occurs when diabetes damages the small blood vessels in the retina, which is the light-sensitive tissue at the back of the eye.
Diabetic retinopathy has different stages. The mildest, called mild non-proliferative diabetic retinopathy, characterized by the appearance of small areas of inflammation, which look like blisters, in the small blood vessels of the retina. As non-proliferative diabetic retinopathy progresses, fluid leaks occur in the retinal vessels, which, when they affect the region of the macula (area located in the center of the retina responsible for “fine and detailed” vision) produces macular edema. Macular edema is the accumulation of fluid below the macula, which causes a vision reduction. On the other hand, blood vessels can become clogged, causing various parts of the retina to stop receiving blood. Then these areas of the retina send signals to the body to grow new blood vessels.
The most advanced stage of diabetic eye disease is proliferative diabetic retinopathy. During this phase, the growth of new aberrant blood vessels (neovascularization) occurs. These new blood vessels are fragile and present a high risk of bleeding, which can lead to significant loss of vision.
Who is at risk for developing Diabetic Retinopathy?
All people with diabetes, both type 1 and type 2, are at risk. That’s why everyone with diabetes should have a comprehensive dilated eye exam at least once a year. It is estimated that, at 15 years of diabetes onset, approximately 15% of diabetics have macular edema, and at 20 years, more than 90% will present some degree of diabetic retinopathy.
The main risk factors for the development of diabetic retinopathy are the duration of the disease, poor glycemic control (high levels of glycosylated hemoglobin), and the presence of high blood pressure.
Keep in mind that diabetic retinopathy can also be a problem for pregnant women with diabetes, so additional eye exams during pregnancy may be advisable.
Symptoms
In early stages, diabetic retinopathy does not present specific symptoms, so the patient may have diabetic retinopathy and not know it. Hence the importance of performing periodic ophthalmological reviews.
As diabetic retinopathy worsens, various symptoms may appear, such as:
· Blurred and / or alternating vision (vision that changes from blurry to clear).
· Appearance of “floaters” (black spots that correspond to small blood clots).
· Distortion of images.
· Alterations and / or defects in the visual field.
· Difficulty seeing at night.
· Decreased visual acuity (both far and near).
· Alteration in the perception of colors.
Is it possible to prevent Diabetic Retinopathy onset?
Adequate control of blood glucose levels and high blood pressure, a healthy diet, exercise, and good health education of the diabetic patient are essential elements that can prevent or delay the onset of diabetic retinopathy.
From the ophthalmological point of view, secondary prevention will be based on an early detection of retinopathy and adequate follow-up.
Diagnosis
The diagnosis of diabetic retinopathy is made, in most cases, by the clinical manifestations associated with vascular abnormalities (neovascularization) that occur in the retina.
In addition to a routine ophthalmologic examination, including examination of visual acuity (far and near), measurement of intraocular pressure, examination of the anterior segment of the eye, and study of the fundus, patients with diabetic retinopathy may require complementary examinations, among which fluorescein angiography and optical coherence tomography stand out.
How often should a patient with diabetic retinopathy be checked?
The pattern of ophthalmological examinations, mainly of the fundus, must be adjusted to the needs of the patients, but as a rule a complete ophthalmological examination should be carried out at the time of diagnosis of diabetes.
In patients with type 1 diabetes, the norm would be a first review 3-4 years after diagnosis and an annual follow-up review. On the contrary, in type 2 patients it is recommended to perform a complete ophthalmological examination at diagnosis and annual follow-up.
Treatment
The best treatment for diabetic retinopathy is prevention.
The treatment of choice varies depending on the degree of disease and patient characteristics.
Treatment of the retina with laser (small burns that close the leaks of the vessels) may be indicated in some patients.
At present, the treatment of choice for proliferative diabetic retinopathy and diabetic macular edema is intravitreal injections of vascular endothelial growth factor inhibitors and implantation of slow-release corticosteroid devices.
In patients with severe proliferative diabetic retinopathy, with the presence of vitreous hemorrhage (blood in the vitreous humor) and / or tractions on the retina, the treatment of choice would be surgery (vitrectomy).
Diabetic Macular Edema
The most common cause of vision loss in patients with diabetic retinopathy is diabetic macular edema.
What is Diabetic Macular Edema?
Accumulation of fluid below the macula (usually due to a leak from blood vessels damaged by diabetic retinopathy), causing a significant loss of visual acuity.
Symptoms
Diabetic macular edema is painless and has no symptoms in its early stages. When you have symptoms, these are:
· Loss of vision and distorted vision.
· Alteration in the perception of colors.
Treatment
Laser photocoagulation has represented the standard of care for the treatment of diabetic macular edema before the advent of medical treatment with intravitreal injections with vascular endothelial growth factor inhibitors or the implantation of slow-release corticosteroid devices.
