What is diabetic macular edema?
Diabetic Macular Edema (DME) is a primary cause of vision loss in diabetic patients. Diabetes mellitus is a chronic disease that affects the body’s blood vessels. Specifically in the eyes, it causes damage to small vessels (microvascular complications due to chronic hyperglycemia), resulting in the formation of new pathological vessels (neovascularization) in the macula, which often bleed.
Diabetes affects blood vessels, causing vascular disease and consequently reduced oxygen transport to the macula. The breakdown of the blood-retinal barrier leads to the leakage of plasma components into the surrounding macular environment, resulting in macular edema. DME is essentially the thickening of the macula due to the accumulation of fluid in its layers (fluid leakage from the interior of dilated capillaries).
The macula is located at the center of the retina and is responsible for central and clear vision. Thus, it is easy to understand that any damage to its structures causes serious disturbances in vision.
Main symptoms
- Blurred vision
- Metamorphopsia
- Scotomas
- Disturbance in color perception
- Significant loss of vision
- Photophobia
Other risk factors
- The stage of diabetic retinopathy
- Arterial hypertension
- Smoking
- Aging
- Hyperlipidemia
- Diabetic nephropathy
It is worth mentioning that one of the factors contributing to the development of DME is a substance called ‘vascular endothelial growth factor’ (VEGF). This induces an increase in the permeability of blood vessels, vascular leakage, and macular thickening, resulting in vision complications.
Types of DME
- Focal macular edema
- Diffuse macular edema
- Cystoid macular edema
Diagnosis
It is advisable for all diabetic patients to be monitored by both an endocrinologist and an ophthalmologist. The diagnostic examination includes:
- Fundoscopy (examination of ocular fundus)
- Fluorescein angiography (detection of damage at the retinal structures)
- Optical Coherence Tomography (OCT) for detailed imaging of the retinal layers and the macula
Treatment
DME can be effectively treated with intraocular injections. These injections contain anti-angiogenic agents (anti-VEGF: anti-Vascular Endothelial Growth Factor) that inhibit the progression of the condition. The ophthalmologist, considering the stage of the condition, follows the appropriate protocol.
Focal photocoagulation laser is a classic therapeutic approach. Using a thermal laser, leaking blood vessels in the macula are cauterized, and the leaks are sealed, preventing fluid entry into the macula.
Surgical intervention with posterior vitrectomy is indicated for cases where edema does not respond to the above therapeutic techniques.
Sources:
Chrysa Koutsiouki MD
Ophthalmic Surgeon
Specialized in Cataract, Medical Retina & Uveitis