AGE-RELATED MACULAR DEGENERATION (AMD)
Straight lines appear crooked especially in the center of the field of vision: When looking at bathroom tiles or a piece of graph paper and lines appear distorted it can be a sign of age-related macular degeneration (AMD). In industrialized countries AMD is the most common cause of severe visual impairment and even blindness in people over 50 years of age.
The retina contains millions of sensory cells (photoreceptors) onto which images of the outside world are projected. The macula is the center of the retina. The sensory cells are particularly densely packed in the macula area, which is a few square millimeters in size, especially cones responsible for color vision. Faces, writing and fine details of the environment are recognized thanks to this small spot – the rest of the retina primarily perceives outlines and light-dark contrasts. Nowhere else in the body are metabolic processes as intensive as in the retina.
The most intensive metabolic processes mean that the macula is susceptible to get damaged as a result of metabolic disorders. Above all, elderly people starting around the age of 60 are affected by this disease.
Underlying the retina is the pigment epithelium. This layer has, among other things, the function of a waste removal: the waste products of the sensory cells are processed and subsequently disposed of as completely as possible. However, with increasing age, residues (fats and proteins) accumulate impairing metabolism. These deposits appear as whitish spots on the retina, so-called drusen, their component (lipofuscin) leads to further damage.
These above-mentioned deposits in the macula impair the supply of nutrients to the retina. The vision of the patients is initially only slightly restricted: colors appear pale and it takes longer for the eyes to get used to the change from light to dark surroundings. Gradually the sensory cells perish. Central vision then becomes significantly worse: for example, you can see that someone is standing in front of you, but you cannot recognize their face. In this “dry form” of macular degeneration, the disease progresses slowly.
In principle, these pathological processes are normal signs of aging – practically everyone would be affected by this disease at some point if they were old enough. Various hereditary and environmental factors determine when the disease appears in each individual: Smoking or high blood pressure can cause macular degeneration to occur earlier. A vitamin-rich diet containing the pigment lutein can protect the macula.
In contrast, a small proportion of patients are affected by the much more aggressive “wet form” of macular degeneration: the pigment epithelium becomes fragile; fine, newly formed blood vessels can penetrate it. But these blood vessels are usually leaky. Leaking fluid leads to swelling in and under the macula, also bleeding is also possible.
Your ophthalmologist has a broad range of examination methods available to identify signs of age-related macular degeneration. The macula and the fundus of the eye can be examined with the slit lamp, a special biomicroscope. Digital photographs can be taken for follow-up documentation. Visual acuity tests can be completed with near eye chart and the Amsler grid. ptical coherence tomography (OCT) allows high-resolution cross-sectional images to assess and differentiate very precisely even small changes in the delicate structures of the retina and macula. Damage to the retina, the pigment epithelium or the choroid as well as the vascular structures can be visualized using digital angiography.
The screening of age-related macular degeneration is becoming increasingly important – the earlier your ophthalmologist can intervene in the disease process, the better valuable vision can be preserved. If, on the other hand, the macular degeneration is already very advanced, patients have the opportunity to optimally use their remaining eyesight with magnifying visual aids – with the help of magnifying glasses it may even be possible to read.
Everyone can prevent age-related macular degeneration with a healthy lifestyle: smoking and high blood pressure are known risk factors. That’s why itis also good for your eyes to stop smoking and check your blood pressure regularly. In particularly bright sunlight – for example at the seaside or in the mountains – sunglasses protect the eyes from UV radiation. A balanced diet with plenty of fruit and vegetables is also considered helpful for prevention. In certain forms of macular degeneration, it is advisable to pay attention to the intake of certain vitamins (vitamin A, vitamin C, vitamin E, ) and carotenoids (lutein, zeaxanthin). These substances, which make up the so-called macular pigment, are mainly found in vegetables such as tomatoes, broccoli, green cabbage or corn. It may also make sense to take appropriate dietary supplements when advised by your ophthalmologist.
Die Altersbedingte Makuladegeneration ist aktuell Gegenstand intensiver Forschung. Im Fall der trockenen Makuladegeneration gibt es momentan leider noch keine sinnvolle Behandlungsmöglichkeit. Bei schon diagnostizierter trockener Makuladegeneration sollen die Sehschärfe und die Netzhaut regelmäßig – alle 6 bis 12 Monate – von Ihrer Augenärztin oder Ihrem Augenarzt kontrolliert werden. Selbstkontrollen mit dem Amsler Gitter können zu Hause durchgeführt werden. Nahrungsergänzungsmittel mit hoch dosierten Radikalfängern, Vitaminen und Lutein können die Netzhaut schützen und sollen verhindern, dass die trockene Makuladegeneration in eine feuchte Form übergeht.
Die feuchte Makuladegeneration lässt sich mit der Gabe von Medikamenten, die direkt in den Glaskörper des Auges gespritzt werden (IVOM, intravitreale operative Medikamentenapplikation) behandeln. Dazu stehen unterschiedliche Wirkstoffe zur Verfügung. Verschiedene Medikamente inaktivieren Wachstumsfaktoren in der Netzhaut, verringern so die Neubildung von Gefäßen und beeinflussen die Undichtigkeit der Gefäße positiv.