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Age-Related Macular Degeneration (AMD)

By Bjarne Lühr Hansen PhD, MD and Philipp Skafte-Holm MD, Mentor Institute

The abbreviation AMD stands for age-related macular degeneration. Today, AMD is the common term for what was previously known as calcification of the retina. It is, however, not a case of calcified blood vessels as seen in e.g. heart and brain, which is why this term has been abandoned.

AMD is an illness in the macula of the retina or the ‘yellow spot’ (in Latin macula lutea and in short form macula). Inside the macula the retina has the greatest concentration of cone cells. It is particularly these specialised ‘cones’ that are responsible for the eye being able to perceive fine details, colours and see the world three dimensional. The illness is often two-sided meaning that it affects both eyes. However, there is often a difference between the degree of severity in right and left eye, respectively.

Today, AMD is the most frequent cause of reading blindness in the developed countries. The illness is often seen from the age of 55 and its frequency increases with age. 12% of the population over 60 years have symptomized AMD and others have an undiscovered eye disease since the nuisances are often quite modest, at the beginning.

The cause of AMD is not known in details. Age, heritage and tobacco are known causes of the development of AMD.

AMD is categorised in two main forms called ‘dry’ and ‘wet’ AMD.

‘Dry’ AMD

The dry form, with waste of the cone cells in the yellow spot, is the most frequent form of AMD (makes out approximately 85% of the cases). In the early stages of dry AMD, there are rarely any symptoms.

However, some patients can tell how they see a dark spot in the ceiling of the bedroom for a few minutes after waking up. Shyness of light can be the first symptom of incipient illness of the retina. Subsequently, difficulties with reading arise because the text looks ‘moth-eaten’.

A sign of AMD can be difficulties with identifying people in the street. This is because when you direct your gaze towards a person the face often disappears because it is located within one of the blind areas of the yellow spot.

The ‘dry’ AMD progresses slowly, as the ability to see details deteriorates. You will have difficulty reading and driving and feel the need to move closer to the TV. It can be necessary with optical aids for reading and watching TV. However, you do not lose your orientation as a result of AMD.

‘Wet’ AMD

The ’wet’ AMD is caused by the development of recently formed blood vessels outside the retina. The growth of these blood vessels is out of control and, therefore, they can grow into the retina itself where their continued growth will lead to haemorrhaging and destruction of cone cells. Unfortunately, this formation of blood vessels takes place in the central area of the retina (macula).

A haemorrhage cause acute symptoms with violent deterioration of sight and distortion of the visual image. This is called metamorphopsia where straight lines winds, letters break in half and faces are distorted.

Usually, the ‘wet’ AMD has a more acute progress than ‘dry’ AMD and the deterioration of sight is experienced over a few days. ‘Wet’ AMD usually leads to permanent reduction of sight.

Further reading on Frequent signs

What can you do?

What can you do yourself

It is important to react and go see the ophthalmologist, in the case of e.g. ‘moth-eaten’ reading vision and distortion of sight (metamorphopsia). The quick development in the treatment of ‘wet’ AMD makes it a good idea to visit the ophthalmologist approximately once a year to be sure not to miss the possibility of treatment. If you know you have AMD, you should visit the ophthalmologist at every change in eyesight. If you have cataract at the same time, it is important to know that even a simple surgery can cause the AMD illness to deteriorate. It is recommended to stop smoking, immediately. Nutritional supplement consisting of large doses of vitamins C and E, a preliminary state for vitamin A (beta-carotene) plus the metals zink and cobber have proven able to slow the development of certain forms of ‘dry’ AMD to a greater or smaller degree.

What can your optician do?

If you have visited your optician because of trouble with reading and during the examination there is raised suspicion of AMD, the optician can acutely refer you to the ophthalmologist.

Contact the doctor tomorrow

If you have signs of AMD and you cannot get an appointment with the ophthalmologist within a week, your doctor can get you an examination with the ophthalmologist.

Contact the doctor immediately

The ophthalmologist diagnoses ‘dry’ or ‘wet’ AMD after a thorough examination of the retina with a dilated pupil. The ophthalmologist can perform a scan of the retina of the eye (OCT scan) and distinguish between ‘dry’ and ‘wet’ AMD.

In some cases, ‘dry’ AMD can benefit from nutritional supplement with vitamins and minerals. If there are signs of ‘wet’ AMD, the ophthalmologist can supplement with an examination with dye (fluorescein angiography); by using this method the ophthalmologist is able to identify leaking blood vessels and plan the treatment in greater detail.

The treatment of ’wet’ AMD is injection of medication directly into the eye (so-called growth inhibiting medication). This treatment must be repeated several times with monthly intervals. From experience, a third of the patients experience better eyesight from this treatment, a third will be unable to register the changes and a third will experience further deterioration of the eyesight. Early treatment has a greater effect and is best for preserving the eyesight.