What treatments for diabetic macular edema?

From lasers to smart drugs, passing through intraocular implants: an overview of treatments and their mechanisms of action.

Diabetic macular edema predominantly affects people with diabetes. It is the most frequent cause of blindness in people of working age. If diagnosed early, it is possible to reduce its progression, reducing symptoms and preserving visual function.

Light therapy

That is, with the laser: it is the retinal laser photocoagulation, which allows to eliminate the inflamed areas, where the production of VEGF (vascular endothelial growth factor) occurs. This is, in fact, the molecule that favors the passage of fluid from blood vessels to retinal tissue, giving rise to edema and swelling.

This procedure, which for years has been the most commonly used therapeutic option, allows to stabilize the disease, but not to recover lost vision.

Curbing inflammation with medication

The study of the molecular and cellular mechanisms underlying diabetic macular edema has allowed the development of alternative therapies to laser. Most of the drugs used aim to block the increase in vascular permeability that underlies the disease. In particular, by acting on some substances, including VEGF.

Anti-VEGF drugs were first used in the treatment of age-related macular degeneration (AMD). Since the two pathologies develop due to the malfunction of some common mechanisms, it has been possible to use these drugs also in the therapy of diabetic macular edema. Treatment is done by intravitreal injection.

The most widely used molecules today are ranibizumab and aflibercept; the latter, in addition to being a broad-spectrum anti-angiogenic (blocks and captures all VEGF isoforms), is also able to modulate PIGF, a placental growth factor also involved in the development of inflammation and permeability of retinal capillaries.

Aflibercept therapy is based on a first phase of “attack”, which consists of five injections on a monthly basis, followed by an injection every two months, during the first year. Following the frequency of injections is reduced according to the patient’s response and the doctor’s assessments.

Intravitreal implants

To interrupt the inflammatory process and thus recover a part of the lost vision, in addition to anti-VEGF drugs, cortisone-based drugs can also be used. By means of a small injection, an intravitreal implant is inserted, i.e. placed inside the eye cavity.

These are small structures consisting of totally biodegradable substances, which contain within them the drug to be administered. The implants, once inside the eye, dissolve slowly, releasing the active ingredient in a controlled and prolonged manner, for a period that can vary from a few months to a few years. These intravitreal cortisone implants are particularly indicated in the case of people resistant to common anti-VEGF drugs. Effects? Speaking of therapy with steroid drugs, possible side effects can be:

• increase in eye pressure, solvable with the intake of specific eye drops
• cataract formation, on which surgery can be performed in day-hospital

Surgery

Surgery is rarely recommended, mainly in cases where the retina is subjected to mechanical stress due to edema.