Why are eyes so prone to damage

Age-related macular dysthrophy

Straight lines appear crooked, especially in the center of the field of vision: If the lines appear distorted when you look at the tiles in the bathroom or on a piece of checked paper, this can be a sign of age-related macular degeneration. In industrialized countries, this disease is increasingly responsible for visual impairments and even blindness in the legal sense.

What is the macula?

The retina - the ophthalmologist calls it the retina - contains millions of light-sensitive cells onto which images of the outside world are mapped. The macula is the center of the retina. The light-sensitive cells, especially the cones responsible for color vision, are located particularly densely on this patch, which is just a few square millimeters in size. We recognize faces, writing and fine details of our environment thanks to this small spot - the rest of the retina mainly perceives outlines and light-dark contrasts. Nowhere in the body do such intensive metabolic processes take place as in the retina.

Why does the macula degenerate?

It is precisely these intensive processes that make the macula susceptible to damage as a result of metabolic disorders. Gradual chronic damage in particular plays a role here. Therefore, older people from around the age of 60 are particularly affected by this disease.

Problems with the "garbage collection"

Under the retina there is a thin layer called the pigment epithelium. Among other things, this layer has the function of garbage disposal: it is supposed to digest the waste products of the light-sensitive cells and dispose of them as completely as possible. However, as you age, residues - fats and proteins - remain and build up until they themselves affect your metabolism. The ophthalmologist will then recognize whitish spots, so-called drusen, on the back of the eye. Part of these deposits is a substance which, when exposed to UV light, leads to further damage: lipofuscin.

Dry and wet macular degeneration

These deposits impair the supply of nutrients to the retina. The patient's eyesight is initially only slightly impaired. Colors appear pale; it takes longer for the eyes to get used to the change from a light to a dark environment. In the late stage, the sensory cells perish. Central vision then becomes considerably worse: For example, you can see that someone is standing in front of you, but you cannot see your face. In this "dry form" of macular degeneration, the disease progresses very slowly.

In contrast to this, a small proportion of patients is affected by the much more aggressive "wet" form of macular degeneration: the pigment epithelium becomes brittle. Fine, newly formed blood vessels can penetrate it. These blood vessels are usually leaky. Leaking fluid leads to swelling in and under the macula, and bleeding is also possible.

These pathological processes are, in principle, normal signs of old age - practically everyone would be affected by this disease at some point if they were old enough. Various hereditary and environmental factors determine the point in time when the disease occurs in an individual: Smoking or high blood pressure mean that macular degeneration occurs earlier; A diet rich in vitamins, which is also rich in the pigment lutein, can protect the macula.

How does the ophthalmologist recognize AMD?

A number of examination methods are available to the ophthalmologist to determine signs of age-related macular degeneration. The ophthalmologist can use the slit lamp, a special microscope, to inspect the macula and the fundus. Digital photographs can be used for documentation in the process monitoring. Functional disorders can be determined on the one hand during the examination with the eye chart and the Amsler grid, on the other hand during an examination of the central visual field with perimetry. Damage to the retina, the pigment epithelium and the choroid as well as the vascular structures can be visualized with digital fluorescence angiography. Optical coherence tomography (OCT) allows high-resolution cross-sectional images of the retina and macula. This enables the ophthalmologist to assess changes in a differentiated manner.

What can i do on my own?

Anyone can prevent age-related macular degeneration with a healthy lifestyle: Smoking and high blood pressure are known risk factors, so it is also good for the eyes to stop smoking if necessary and to check your blood pressure regularly. In particularly bright sunlight - for example by the sea or in the mountains - sunglasses protect the eye from UV radiation. A balanced diet with plenty of fruit and vegetables is also helpful for prevention. With certain forms of macular degeneration, it can be useful to pay attention to the intake of certain vitamins and lutein. These substances, which make up the so-called macular pigment, are mainly found in vegetables such as broccoli and corn. It can also be useful to take appropriate dietary supplements.

How does the ophthalmologist treat?

Macular degeneration in particular is the subject of intensive research. In the recent past, new treatment methods have been developed that can at least stop the disease process. In some cases of dry macular degeneration, rheopheresis offers a treatment option. Proteins that reinforce the disease process are eliminated from the blood. In the early stages of wet macular degeneration, the ophthalmologist can use a laser beam to obliterate sprouting and leaky vessels. In many cases, photodynamic therapy is an effective treatment: First, a substance is injected into the arm vein. It makes the vascular growths in the eye sensitive to the laser beam.

Administration of medication directly into the eye

Wet macular degeneration can also be treated with medication that is injected directly into the vitreous humor of the eye. Various active ingredients are available for this purpose. Various drugs inactivate growth factors in the retina and thus reduce the formation of new vessels, and this also has a positive effect on the leakage of the vessels. Cortisone preparations can also be injected directly into the vitreous humor: this seems to reduce the number of necessary re-treatments, especially in combination with photodynamic therapy.

surgery

In some situations, vitreous removal surgery is necessary to remove bleeding and neovascularization. In rare cases it can be helpful to lift and rotate the retina or to line the central retina with a piece of pigment epithelium from the outer retina in order to improve the metabolism of the macula. If the macular degeneration is already very advanced, the patients can make optimal use of the remaining eyesight with magnifying visual aids. With the help of magnifying glasses it may still be possible to read.

Intervene early

The early detection of age-related macular degeneration is gaining in importance. Because the earlier the ophthalmologist can intervene in the disease process, the better valuable eyesight can be preserved.

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