Age-related macular degeneration, age-related macular degeneration or AMD for short, is a progressive damage of the epithelial tissue (pigment epithelium) and the photoreceptors in the retina. The damage of the tissue leads to a loss of function and thus to a severe reduction of visual acuity in old age. The following text discusses the definition, causes, diagnosis and progression, as well as treatment and preventive measures of age-related macular degeneration.
What is age-related macular degeneration?
Schematic diagram showing the anatomy of the eye and the difference between healthy eye and macular degeneration. Click to enlarge. Age-related macular degeneration is a disease of the retina (retina). In particular, it affects the site of sharpest vision, the macula lutea (also known as the “yellow spot“). Due to a malfunction of the pigment epithelium, age-related macular degeneration leads to an accumulation of metabolic products in the retina. This leads to the formation of so-called drusen, which result in the destruction and thinning of the pigment epithelium normally found there. Consequently, the neighboring photoreceptors are also impaired in their function. Photoreceptors are light-sensitive sensory cells, with the cones being responsible for color stimuli and the rods for twilight vision or black-and-white vision. Age-related macular degeneration is a disease of older age and usually begins after the age of 60.
Causes
Depending on the clinical appearance, a dry and a wet course form of age-related macular degeneration are distinguished. Diagnosis is made by ophthalmoscopy, a reflection of the back of the eye and a visual field examination. At home one can also perform an Amsler grid test for early detection of age-related macular degeneration. Thereby one sees a white grid on a black background or inverted. A point in the center is fixed. If you see distorted lines, squares of different size, missing corners or blurred areas you should consult an ophthalmologist as soon as possible. More rarely, fluorescein angiography is used to diagnose age-related macular degeneration; a contrast agent is injected into a vein. The retina is then photographed.
Symptoms, complaints, and signs
In this disease, patients primarily suffer from visual complaints. Although the severity of the visual complaints can vary greatly, there is always a marked reduction in visual acuity. Patients can no longer see sharply, and contrasts can no longer be recognized correctly. Vision is often distorted and very blurred, resulting in significant limitations and complications in everyday life. In the further course, the disease can also lead to complete blindness in the patient. Visual complaints can also lead to psychological limitations or depression in some people. Severe visual complaints also increase the risk of injuries and accidents. If the condition is not treated, hemorrhages and irreversible damage to the patient’s retina will occur as the condition progresses. Even after successful treatment with the help of a laser, a relapse can occur, so that the same symptoms reappear. In this case, no further treatment or cure is possible. In some cases, the disease can also negatively affect color vision, so that the patient can no longer recognize different colors correctly. Color blindness may also occur in this process.
Diagnosis and course
In the dry course form of age-related macular degeneration, hard drusen appear that are sharply defined and yellowish in appearance. As the disease progresses, the number and size of the drusen increase, and they may coalesce to form an area. This leads to a decrease in visual acuity. The dry form of age-related macular degeneration shows a central scotoma (site of attenuation) on visual field examination. A more severe course of age-related macular degeneration is the wet form. Here soft drusen with a fluid accumulation under the pigment epithelium show up. This corresponds to a pigment epithelial detachment. Patients complain of sudden distorted vision (metamorphopsia) with simultaneous decrease of visual acuity.Furthermore, in this form of age-related macular degeneration, vascular neovascularizations are observed, which lead to further damage of the pigment epithelium and the photoreceptors. This damage is irreversible and can occur very rapidly. Hemorrhages into the retina may occur. Affected persons show only a minimal peripheral visual field and can only roughly orient themselves in space. Reading is no longer possible. In this wet form of age-related macular degeneration, fluorescein angiography is performed to assess new vessel formation.
Complications
Age-related macular degeneration (AMD) occurs in two distinct courses, dry and wet AMD. The dry form of progression is the one with the slower progression. In it, tiny deposits can be seen in the macula, the tiny area of central vision that is only a few millimeters in size, which gradually leads to impairment of central vision. The biggest complication that can be associated with dry AMD is the risk that it will progress to the wet course form. This means that new blood vessels then grow into the area of the macula, also called the yellow spot, causing hemorrhages into this area of the retina due to their leakiness. The hemorrhages are accompanied by progressive deterioration of central acuity and color vision. To date, there is no known treatment for dry AMD beyond treating the symptoms. The level of likelihood that dry AMD will develop into wet AMD is independent of whether dry AMD has been treated in its early stages. Other complications associated with disease progression of either AMD course are not known. Two different therapeutic approaches are available for the treatment of wet AMD. One is to suppress new vessel formation via the messenger VEGF, and the other is to use laser technology to obliterate new vessel formation.
When should one go to the doctor?
If changes in visual perception of a permanent character can be detected in the central visual field, it is recommended to have the altered visual perception clarified by an ophthalmologist quite soon. If the central visual field is seen blurred despite glasses, the color contrast is reduced or distortions or even zones with total loss are present, there is a suspicion of a developing age-related macular degeneration (AMD). A self-test, the so-called Amsler grid test, can also be performed with simple means to confirm the suspicion. It is a relatively close-meshed grid, which is formed by squares and has a clearly visible black dot in the middle. The grid can be easily found on the Internet under the keyword “Amsler grid”. The grid is viewed from normal reading distance alternately with the left and right eye, covering the other eye in each case. If the dot or individual squares of the grid appear distorted or disappear completely, there is a strong suspicion of AMD disease. In these cases, an ophthalmologist should be consulted immediately for clarification. If the suspicion is confirmed, the ophthalmologist can initiate therapy that can slow or even stop the disease, taking into account whether the condition is the more common dry or the less common wet form of AMD.
Treatment and therapy
Treatment for age-related macular degeneration is based on whether the form is dry or wet. No intervention is currently available for dry age-related macular degeneration. Visual aids such as illuminated magnifiers, magnifying glasses, or television readers may be prescribed. For the wet form of age-related macular degeneration the progression of the vascularization can be temporarily stopped in the early stage. For this purpose a laser coagulation of the newly formed vessels is performed. However, this success is only short-lived. Often recurrences (relapses) of age-related macular degeneration occur within 2 years, which then can no longer be treated. A medicamentous therapy remained so far without further success. With a photodynamic therapy the development process of a wet form of age-related macular degeneration can be slowed down, but not terminated. Thereby a vasotoxic substance is injected intravenously. The toxic substances are only activated by laser light.Destructive new vessel formation can be slowed down and the affected person will have better vision for a longer time.
Outlook and prognosis
Due to macular degeneration, the affected person mainly suffers from discomfort in the eyes. As a rule, the visual acuity is significantly reduced, so that the affected person can only see indistinctly. The everyday life of the patient is made much more difficult by the macular degeneration. Likewise, contrasts can no longer be displayed correctly, so that the patient’s quality of life is greatly reduced. In the worst case it can come to a complete blindness. Often the macular degeneration also has a negative effect on the color vision of the affected person. Usually it is not possible to treat macular degeneration directly. In some cases the symptoms can be corrected by a laser. However, this cannot exclude the possibility of a renewed relapse of the macular degeneration. In this case, unfortunately, no further correction can be made. However, the complaints can be limited relatively well by visual aids. The life expectancy of the affected person is not limited by macular degeneration.
Prevention
Preventive measures of age-related macular degeneration unfortunately do not exist. Insofar as distorted lines or a blurred image are perceived, an ophthalmologist should be consulted at an early stage.
Follow-up
Age-related macular degeneration (AMD) is divided into the more common dry macular degeneration and the more rare wet macular degeneration. For both, early detection is more important than follow-up care. If as a result of the age-related macular degeneration already visual impairments have occurred, these cannot be remedied medically. However, an immediate treatment can preserve the remaining vision. Dry macular degeneration progresses slowly and insidiously over several decades. The earlier it is detected, the better the treatment can be. Ideally, the eye disease can be stopped, otherwise it can be slowed down. Careful and regular monitoring of the course of the disease is essential in follow-up care. In wet AMD, the progression is rapid. It is accompanied by retinal damage. In order to interrupt the process of vision loss in age-related macular degeneration, physicians today increasingly try to prevent vision loss by intravitreal drug injection into the vitreous under local anesthesia. The numerous consequences of the wet form of age-related macular degeneration are serious. Vision is lost rapidly without immediate treatment. Vision loss already suffered is beyond repair. Consequently, if treatment begins too late, aftercare can only consist of helping sufferers cope with life despite their lost vision.
Here’s what you can do yourself
Self-help methods outside of medical or clinical treatment that could halt the progress of age-related macular degeneration (AMD) or even cure it are not known. A combination of self-help measures with medical treatment methods can be done in a systemic treatment, which is based on nutrition and requires the special cooperation of the patient. To detect AMD, the so-called Amsler grid test can be performed at any time as a self-help measure, by means of which every affected person can recognize whether he or she has a high probability of AMD and how severely central vision is impaired. The Amsler grid can be easily found and accessed on the Internet. It consists of an image of a grid consisting of square fields with a clearly visible black dot in the center. The grid is viewed from a normal reading distance with reading glasses – if necessary – alternately with the right and left eye, while the other eye is covered. If some squares – especially near the black dot – and the dot itself appear distorted or are not visible at all, there is a high probability of AMD with dry or wet progression. In persons with already far advanced disturbance of central vision, for example, movies and videos or TV programs are helpful if they have acoustic descriptions of actions on demand during the short breaks in dialogue for support.
