Monnett Eye & Optical Center

Macular degeneration is a disease of the macula, a small highly sensitive small central area of the retina that produces detailed and color images in the center of the field of vision. The macula is important for everyday tasks. Macular degeneration (MD) occurs when the macula is damaged and usually affects both eyes, but it may produce symptoms in one eye long before the other.

Age-related macular degeneration (AMD) is the leading cause of severe vision impairment in older Australians.

AMD occurs when central vision deteriorates, making reading, close work and recognising faces more difficult.

The most common forms of the condition are Dry and Wet AMD. Dry AMD results in a gradual loss of central vision and Wet AMD leads to sudden and significant changes in vision.

How does AMD develop?
This is an aging change and occurs because of 'wear and tear' changes in the macular region. It is thought that waste materials from this very active part of the eye build up as the mechanisms for removing them become less able. This causes damage to the cells over a period of time.


Who is at risk of age-related retinal degeneration?
This condition tends to affect people who are over 60 years of age. Some younger people may be more susceptible, including people who are very short-sighted. Women tend to be affected more commonly than men, but that is probably because they live longer. There is a hereditary tendency, but this has not yet been fully researched.
What are the different types of macular degeneration?

There are two major types of AMD. These are described as dry or wet.

• Dry AMD: This is the more common form of AMD and affects almost 80 per cent of those with the condition. The onset of this condition tends to be slow. Both eyes are usually affected symmetrically.

• Wet AMD Wet macular degeneration is less common but tends to have a more severe and rapid effect on the central area of vision. In this condition, blood vessels from one layer at the back of the eye grow in an abnormal fashion into the macular area. These blood vessels may leak or bleed causing a rapid and significant reduction in central vision. This tends to affect one eye at a time but there is a risk of the same thing occurring in the other eye over the following months.

What are the symptoms of age-related retinal degeneration?
Dry AMD causes a gradual reduction in central vision. This tends to affect the ability to read and to see fine detail more than distance vision.

The first symptoms of wet AMD may be distortion of vision (known as metamorphopsia). This often has the effect of making straight lines appear curved or tilted. The vision deteriorates and eventually the central vision may be completely lost leaving a dark central area of poor vision (known as a central scotoma).

Dry AMD
The vision tends to deteriorate gradually and the loss of vision is not always severe. Treatment involves wearing the best spectacles and possibly using bright lights for example halogen light to help you see things more clearly. The use of large print books and the prescription of a magnifying glass (low visual aid) are often necessary.

Wet AMD
In order to determine whether a patient would be suitable for treatment, further evaluation in the way of visual assessment with special letter charts and imaging of the retina can be carried out. Imaging of the retina involves a fluorescein angiogram and a scan of the back of the eye (retina) with an OCT (optical coherence tomography) machine.

The fluorescein angiogram procedure involves a dye being injected into a vein of the arm and then a series of photographs are taken of the back of the eye. An OCT scan is used to look for macular degeneration under the retina and this scan usually takes only a few minutes to perform.

If wet AMD is confirmed, treatment is implemented urgently.

There are currently two ways in treating wet AMD, firstly with injection of medication into the back of the eye and secondly with laser treatment.

Depending on the level of vision and retinal imaging, some wet AMD may be suitable for injection into the back of the eye. These drugs appears to work by preventing the formation of abnormal new blood vessels in the eye. It also dries up vessels which have already begun to leak, stopping further damage.

Additonally, laser treatment photo-dynamic therapy (PDT) which uses a light-sensitive dye called verteporfin (Visudyne) in combination with laser treatment is also sometimes used to treat certain kinds of wet AMD. The dye is first given by injection and then the laser is used to activate the dye and close off the new blood vessels that cause the damage.


What can be done to avoid getting AMD?
There has been much discussion about the role of high dose vitamins in preventing this condition, but there is no evidence to support this.

A person who has wet AMD in one eye should have the vision in their other eye regularly assessed so that early signs of distortion are picked up rapidly. This can be done by looking at picture frames or by using an Amsler Chart we can provide to them.


Monnett Eye Center recommends regular assessment by one of our eye care professionals for complete ocular health assessment, including the macular.

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