The macula or yellow spot is a small area of approximately three millimeters in diameter in the center of the retina. The visual axis of the human eye runs precisely through this point. Since the density of color-sensitive sensory cells is highest in the area of the macula, the highest resolution is achieved there, i.e. when we read a text, it is displayed exactly in this area. Retinal changes in this area are correspondingly dramatic and have a major impact on visual acuity.
In macular edema, fluid builds up inside the retina. This can be detected on the slit lamp during fundus copy (retinal endoscopy). In order to be able to accurately diagnose macular edema, so-called ocular coherence tomography (OCT) is used today.
Macular edema worsens visual acuity and straight lines are typically perceived as curved.
The Amsler grid can be used to diagnose macular edema. The test subject looks at a central point and pays attention to whether the grid lines around it appear straight or curved.
The fine capillaries of the central retina leak and fluid leaks into the surrounding macular tissue. There are various reasons for capillary leakage:
Depending on the cause of the edema, different treatment routes are taken:
Diabetes, AMD or vascular occlusions cause increased release of VEGF (vascular endothelial growth factor) in the eye. These growth factors cause blood vessels in the area of the retina to leak and fluid to leak into the macula. Anti-VEGFs are artificially produced antibodies that bind VEGF and thus inhibit its effect. The vessels are therefore virtually sealed by the anti-VEGFs.
The patents for ranibizumab and aflibercept have recently expired and the first so-called “biosimilars” have come onto the market. In contrast to generic drugs, the structure of “biosimilars” differs more from the original drug. Like the original products, “biosimilars” are also subject to an approval process, which is significantly shorter. As a result, these new “biosimilars” are less well tested compared to the original preparations. We therefore currently only recommend original preparations.
The active ingredient is injected into the eye as a liquid solution using a syringe. An injection in the eye may sound very alienating and cause anxiety for many patients, but pain is very rare. The majority of patients report that any anxiety about the injection has disappeared after the first treatment.
The treatment takes a few minutes and is performed on an outpatient basis. Intravireal injections generally do not require anesthesia. Before the procedure, the surface of the eye is made insensitive with anesthetic eye drops.
In order to minimize the risk of an infection in the eye, the treatment takes place on a couch in a sterile operating room. The eye is disinfected with a chlorhexidine or iodine solution and then covered in a sterile manner. An eyelid holder is used to keep the eye open, after which the conjunctiva is also rinsed with disinfectant. Using a very thin cannula, the medication is slowly injected through the connective and sclera into the vitreous body inside the eye.
The areas below and above the cornea are best suited for injection as they are protected by the eyelids and are less sensitive. In order to reach these areas, the patient should look up or down.
As a result of the treatment, the eye often feels sandy for a few hours. Shortly after the injection, floating black dots may also be noticed in the visual field, which usually disappear after a few hours to days. In addition, bleeding visible from the outside may occur in the area of the connective or sclera. The blood dissolves again after a few days. In rare cases, there may be bleeding in the vitreous cavity. This can lead to a temporary impairment of vision. The blood usually dissolves within four to six weeks.
Sudden head movements during injection may damage the lens or retina, resulting in cataracts, slipping of the artificial lens, or retinal detachment.
Moisturizing eye drops or eye ointment (e.g. vitamin A eye ointment) can help if you feel sandy. Prophylactic antibiotic eye drops are generally not needed after intravireal injections.
Visual acuity usually only becomes visibly better after several treatments at first.
During follow-up checks, we perform an eye test, examine the eyes for possible side effects of the injection and document the macular edema with an OCT examination.
Each patient responds differently to anti-VEGF agents; as a rule, several injections are required to treat macular edema in the long term.
As a result of the OCT images, the time intervals from one injection to the next can be extended if improved or shortened again if worsened. This treatment regimen is called “Treat and Extend” and is currently the gold standard for treating most types of macular edema. The aim of intravireal therapy is to achieve a good, stable condition with as long distances as possible.
Like anti-VEGF preparations, cortisone is also effective in treating macular edema in particular in:
If the anti-VEGF preparations do not work or do not work well enough, steroid injections are used as a so-called “second line” therapy:
There may be an increase in eye pressure after the injection. In addition to Triamcinolone® (solution), there are also fixed dexamethasone implants (Ozurdex®), which, like a depot, evenly release cortisone into the eye over several months.
The patient can perceive these implants until they are completely dissolved. Steroids can cause clouding of the natural lens, which later leads to cataract surgery can make necessary.
If left untreated, visual acuity that makes it possible, for example, to recognize faces, read and watch television, is unlikely to be maintained. A further worsening or loss of visual function is very likely if left untreated. If macular edema persists over a long period of time, structural damage occurs that is not reversible.
