Diabetic Retinopathy

Diabetic retinopathy occurs when uncontrolled high blood sugar damages the blood vessels supplying oxygen to the retina. This leads to retinal damage and decreasing vision. Anyone with diabetes is at risk for developing diabetic retinopathy. The longer a person has diabetes, the greater their chance of developing diabetic retinopathy. It is one of the leading causes of blindness in the world and in Egypt.

Diabetes damages the retina in two ways.

The first, known as non-proliferative diabetic retinopathy, occurs when the blood vessels of the retina begin to bleed or leak fluid. This results in retinal swelling (macular edema), small hemorrhages, and the formation of deposits known as exudates.
The second way that diabetes damages the retina is known as proliferative diabetic retinopathy. This is a more severe type of retinal damage. It occurs when blood vessels in the retina or optic nerve become blocked, consequently starving the retina of necessary nutrients. In response, the retina grows new blood vessels (neovascularization). Unfortunately, these new vessels are abnormal, causing bleeding or formation of scar tissue.

Proliferative diabetic retinopathy may lead to any one of the following:

Vitreous hemorrhage – the new vessels bleed profusely into the eye, blocking vision.
Retinal detachment – scar tissue pulls on the retina, causing it to tear or detach.
Neovascular glaucoma – abnormal blood vessels block drainage of fluid out of the eye, causing high eye pressure.

Diagnosis

Fluorescein Angiogram
Diabetic retinopathy is diagnosed with a dilated exam of the retina by an ophthalmologist. The ophthalmologist may wish to study the retinal blood vessels with photographs or by using a test called fluorescein angiography. During this test, a dye is injected into the arm and quickly travels throughout the blood system. Once the dye reaches the blood vessels of the retina, a photograph is taken of the eye. The dye allows the ophthalmologist to detect damaged blood vessels as they leak into the retina.

Optical Coherence Tomography
The posterior segment OCT allows us to take a cut section of the retinal central region; the macula so as to determine the degree of swelling or edema, and to monitor the response to treatment.

Prevention

The best way to prevent diabetic retinopathy is through strict control of blood sugar and blood pressure. These measures significantly reduce the risk of long-term vision loss. With annual eye exams and prompt treatment of diabetic retinopathy, few people progress to serious vision loss.

Treatment

In the early stages of diabetic retinopathy, the blood vessels in the eye leak, causing swelling of the retina. For decades, this swelling has been treated with retinal laser, which has been shown to slow the progression of vision loss. Recently, ophthalmologists have also been injecting anti-leakage medicines into the eye. These medicines include steroids such as triamcinolone acetate and anti-vascular endothelial growth factors (anit-VEGF) such as Avastin or Lucentis. In combination with laser, these injections have been shown to reduce retinal swelling and improve vision loss.