Age-related macular degeneration

Age-related macular degeneration is believed to be caused by an overload of the photoreceptors, which is why the disease does not appear until old age. This is because, in the course of life, the photoreceptors have to break down large quantities of metabolic products every day. When they eventually become exhausted, these degradation products accumulate in the so-called drusen. However, these drusen cause the photoreceptors responsible for colour and black-and-white vision to die. As a result, the density of light-sensing cells suffers and these cannot regenerate. 

In addition, blood vessels often grow into the retina. This process creates oedema as water accumulates under the retina and lifts off the pigment layer. Wet macular degeneration is the result. 

If your vision changes suddenly or gradually, you should be alert and always consult a doctor. Macular degeneration can be recognised by the following symptoms:

• dry macular degeneration:  Here, the visual impairment develops slowly over a long period of time. At first, vision deteriorates when reading, for example. As the disease progresses, a grey spot appears in the centre of the field of vision and does not disappear.
• wet macular degeneration: The wet form develops from a dry one. The symptoms get worse more quickly and soon reading is no longer possible. Recognising faces becomes difficult. Sometimes only rough outlines are visible. Also a typical sign of the presence of AMD: Objects appear distorted and lines look curved. 

An eye specialist can carry out the following examinations to confirm the diagnosis:

• Amsler grid test: This eye test is used for early screening for AMD. If the lines of the grid are perceived as distorted, further examinations should follow to confirm the suspicion of macular degeneration.
• Fluorescein angiography: Fluorescein angiography involves injecting a dye into the patient's arm vein. After a short time, this colour spreads to the blood vessels in the eye. This allows the doctor to detect vascular changes with a special camera.
• Optical coherence tomography (OCT): Using OCT, the eye specialist measures the thickness of the retina, which provides information about the type of AMD. In dry AMD, the retina is usually thinner than in a healthy retina, whereas in the wet form it is thicker.

The best chance of treatment lies in early detection of the eye disease. This allows an eye specialist to detect the drusen during the examination before they cause problems for the patient. Changes in the retina can also be treated at an early stage by screening. In general, however, specific treatment is difficult; therapy is usually aimed at preserving the eyesight for as long as possible.

• Treatment of dry AMD: The dry type is hardly amenable to treatment. The best chance of success is to take certain supplements such as lutein, zinc and carotenoids. This can at least delay progression of the disease. Visual aids and magnifying spectacles enable those affected to read and find their way around in everyday life.
• Treatment of wet AMD: Wet macular degeneration is usually treated by injecting VEGF (vascular endothelial growth factor) inhibitors into the eye. They inhibit the excessive growth of blood vessels into the centre of the retina. In some cases, they may even resolve. The injections are administered directly into the vitreous body three times at intervals of four to six weeks. The eye is anaesthetised beforehand, rendering the procedure completely painless.  

More rarely and only under special conditions is photodynamic therapy (PDT) or surgery performed.