Brief overview
- Description: Fluid accumulation (edema) at the point of sharpest vision (macula) of the retina, occurs relatively often in diabetes mellitus, leads untreated to vision loss
- Treatment: Depending on the cause, laser therapy, injections into the eye, rarely eye drops.
- Prognosis: Early diagnosis usually well treatable, untreated vision loss possible
- Symptoms: Often occurs insidiously, blurred and indistinct vision
- Causes: Diabetes mellitus or disorders of the retinal-blood barrier, as well as eye surgery and inflammation
- Diagnosis: Based on symptoms, ophthalmologic examination using slit lamp, optical coherence tomography and fluorescein angiography
- Prevention: Best possible therapy of diabetes mellitus, regular retinal examinations, consider risk factors in eye surgeries
What is macular edema?
While cystoid macular edema is becoming less common due to improved surgical techniques, the incidence of diabetes is increasing. According to the Robert Koch Institute, the figures for the incidence of diabetes mellitus have increased almost tenfold since the 1960s. Especially in the age group over 65 years, about every fifth person shows diabetes mellitus (women: 17.6 %, men: 21.1 %). Diabetic macular edema is the leading cause of reduced vision or blindness in people between the ages of 20 and 65.
What is diabetic macular edema?
Diabetes mellitus causes long-term vascular damage, including damage to the small blood vessels that supply the retina of the eye. When this complication occurs in people with diabetes, doctors refer to it as diabetic retinopathy. If left untreated, the retinal disease caused by diabetes leads to blindness in many cases.
The visual impairment caused by diabetic macular edema is caused by fluid buildup on the retina and retinal thickening of the macular center or near it. The risk of blindness depends on how severely the retinal vessels are affected and the location of the macula where the edema occurs: the closer it is to the macular center, the more severe the vision loss.
What is cystoid macular edema?
After surgery, fluid builds up in the retina of the eye and accumulates in small cysts or vesicles in the macula. In severe cases, several of these cysts close together and cause deep damage to the retina.
In some circumstances, cystoid macular edema also results from other causes, such as inflammation.
How can macular edema be treated?
The treatment of macular edema depends on the particular cause, for example diabetes mellitus or cataract surgery.
Treatment of diabetic macular edema
First and foremost is the treatment of the underlying disease, diabetes mellitus, with particular emphasis on the control and optimal adjustment of blood glucose and blood pressure.
If diabetic macular edema is present, the physician will base the treatment options on the severity and extent of the macular edema. Basically, there are two ways to treat diabetic macular edema:
Laser therapy
Laser treatment is used to treat diabetic macular edema that does not involve the retinal center (fovea). The primary goal of this treatment is to stop the progression of visual impairment and stabilize visual acuity.
Intravitreal injections/injections into the eye
If the retinal center (fovea) is affected in diabetic macular edema, doctors usually first suggest administering medication into the eye by injection. The aim of this treatment is to reduce macular edema and improve vision.
This treatment is also performed in specialized ophthalmic practices or eye clinics, usually on an outpatient basis. As a rule, intravitreal injections are not associated with pain, since the eye is anesthetized before the injection. So-called VEGF inhibitors are primarily injected.
VEGF stands for “Vascular Endothelial Growth Factor”. This factor ensures the formation of new blood vessels and is inhibited by the injection of VEGF inhibitors. These drugs are among the newer therapies for macular edema.
Injections are given monthly in most cases, up to twelve times a year. The therapy may be carried out for several years, usually the number of injections per year decreases.
The duration of therapy is much shorter here: those affected receive an injection from their doctor every three to six months. There is now also an implant with corticosteroids that lasts up to three years.
At the same time, however, the therapy also has side effects: For example, the risk of increased intraocular pressure and the development of a cataract must be weighed together with the doctor.
In diabetic macular edema with involvement of the retinal center, laser therapy may also be used or added.
Treatment of cystoid macular edema
Most cases of cystoid macular edema occur after cataract surgery. Many heal on their own and do not require therapy. However, a physician must periodically examine the development. Cystoid macular edema results from inflammation or blocked blood vessels, among other things. If this is detected, the doctor adjusts the therapy individually.
If cystoid macular edema must be treated, the ophthalmologist prescribes, for example, anti-inflammatory eye drops containing cortisone or administers cortisone injections into the eye.
What is the prognosis of macular edema?
The cause and timing of diagnosis affect the prognosis of macular edema. The earlier a diagnosis is made, the sooner therapy is given and the more favorable the prognosis.
In diabetic macular edema, the early diagnosis of macular edema, the response to therapy and the initial situation (previous diseases, etc.) of the affected person are decisive factors for the prognosis of the disease. With appropriate treatment, vision stabilizes in many cases, and in some cases vision improves again.
What are the symptoms of macular edema?
The symptoms of macular edema depend, among other things, on the severity and extent. Many affected people notice changes especially when reading or driving, they suddenly see blurred and out of focus. Patients with macular edema also experience blotchy vision or impaired perception of colors. In some cases, there are no symptoms; in others, they begin insidiously and cause only mild visual disturbances. Often, the signs of macular edema are noticed late.
Especially if you have diabetes mellitus, it is advisable to have regular checks for macular edema at your ophthalmologist.
What is the cause of macular edema?
In addition, different characteristics of the underlying disease diabetes mellitus play a role. Thus, diabetic macular edema occurs more frequently the longer the diabetes exists and the more severe the diabetic retinopathy becomes. The inflammatory processes that occur in the body during diabetes also seem to have an influence on the development of macular edema.
Why cystoid macular edema (CME) occurs after surgery is not yet fully understood. Currently, physicians consider the main cause to be the presence of inflammatory processes and neurotransmitters that are released by surgery and also influence the permeability of the blood vessels.
How is macular edema diagnosed?
The ophthalmologist diagnoses macular edema based on the symptoms described, a vision test, and various ophthalmologic examinations. A slit lamp (a special microscope used by ophthalmologists) can be used to view and evaluate the retina and diagnose macular edema.
Furthermore, a type of ultrasound examination called optical coherence tomography (OCT) may be performed. This enables the doctor to assess the eye tissue more precisely. In many cases, public health insurers do not cover this examination. OCT is often used to monitor the progression of macular edema.
For these examinations, the pupils must be dilated beforehand. This is done by administering certain eye drops. Remember that your eyes may be sensitive to light during this time; sunglasses will help. In addition, it is advisable not to drive a car or ride a bicycle for a few hours afterwards until the effect of the drops wears off.
How can macular edema be prevented?
The prevention of diabetic macular edema is primarily done by treating the underlying disease, diabetes mellitus. Here regular controls and a good adjustment of blood sugar and blood pressure are decisive. In addition, regular control examinations at the ophthalmologist are part of the prophylaxis of macular edema.
In case of cystoid macular edema, which occurs mainly after cataract or other eye surgeries, a careful preliminary examination is important. In this regard, your surgeon will pay special attention to risk factors. These include:
- Pre-existing conditions such as diabetes mellitus or high blood pressure
- Anatomical features that complicate the surgery
- Certain pre-existing conditions of the eye, such as uveitis (inflammation of the medial eye surface) or a history of retinal vein occlusion
- Certain medications (e.g., prostaglandin analogs for glaucoma)
