Diabetic retinopathy

Type 2 diabetes affects more and more people around the world. It causes a variety of long-term complications that influence not only the individual patient, but the society in general, because the disease usually affects people of active age. During the last two decades the diabetes morbidity has increased substantially and this tendency is expected to remain in the years to come. The reasons for that are complex, but most commonly diabetes is associated with changes of the human diet, the lack of physical activities and the sedentary lifestyle of the contemporary people.
Diabetes patients often develop eye-related complications such as corneal deformations, glaucoma, neovascularization of the iris, cataracts and neuropathies. The most common and threatening the sight complication remains the diabetic retinopathy (DR), which is one of the leading causes for vision loss in the age between 25 and 74.

Symptoms: In the early stages of DR there are no apparent visual symptoms. In time patients can experience floating blind spots, blurred vision, progressive deterioration in visual acuity. Some of the clinical signs of DR include:
- microaneurysms - the earliest clinical sign of DR; they are small red spots on the superficial retinal layers;
- retinal hemorrhages;
- vitreous hemorrhages;
- Retinal edema and rigid exudates;
- soft exudates;
- macular edema.

Diabetic retinopathy has two forms:
1) Non-proliferative and
2) Proliferative DR;
Non-proliferative DR – 90% of the cases:
- mild form;
- moderate form;
- severe form – including hemorrhages, microaneurysms, macular edema and venous problems.

Proliferative DR:
- neovascularization - the hallmark of PDR;
- preretinal hemorrhages – they occur in the area between the vitreous and the retina;
- vitreous hemorrhages;
- fibro-vascular tissue proliferation;
- transient retinal detachment / lifting;
- macular edema.

Diagnosis:
Laboratory tests and HbA1c hemoglobin levels are of utmost importance for the long-term medical supervision of patients with diabetic retinopathy. The following tests are also likely to be used to diagnose DR:
- Fluorescein angiography - contrast retinal vascular imaging;
- Optical Coherent Tomography (OCT) - measuring the thickness of the retina and the presence of macular edema;
- Ultrasound echography.

Treatment:
1) Medication treatment:
- Growth hormone-releasing hormone antagonists – combination of medicaments, discovered and developed in the last 5-10 years mainly used for treatment of the diabetes-related macular edema;
- ntravitreal corticosteroid injections.
2) Glucose control - „The Diabetes Control and Complications Trial” proved that strict control of the glucose levels of diabetes patients decreases the retinopathy progression.
3) Laser photocoagulation – applying monochromatic light energy to achieve controlled coagulation of the retinal tissue. There are various laser techniques, used depending on the type of diabetic retinopathy and the degree of changes occurring.
4) Vitrectomy - surgical technique that could be used in proliferative diabetic retinopathy in case there are complications such as persistent vitreous hemorrhages and traction retinal detachment.
5) Cryotherapy - method of lowering the intraocular pressure in extremely advanced and complicated stages of proliferative diabetic retinopathy.

Long-term medical supervision:
How often you need to visit your doctor depends on the stage of the diabetic retinopathy. Only 5% of the patients with a mild form of non-PDR progress to PDR in a period of 1 year, so you don’t need more frequent examinations than once every 12 months. Almost 27% of people with moderate non-PDR would progress to PRD in the space of one year so they need to visit their ophthalmologist every 2-3 months. In cases of macular edema, the patient should be treated in due time.