Macular degeneration is a common cause of vision loss. Also known as ‘Age related macular degeneration’ or “ARMD” for short, this does not mean that loss of vision is ever a normal part of getting older.
Instead, this is a disease which needs to be diagnosed and can be treated. At FEC we have the equipment and expertise to assess your eyes for this condition and to advise you about the best available treatment.
General information about macular degeneration
In many cases, macular degeneration advances so slowly that people notice only minor changes in their vision. However, in around 30% of people with this condition it can progress faster and may lead to a loss of vision in both eyes. ARMD is a leading cause of vision loss in New Zealanders 60 years of age and older.
People often refer to Macular Degeneration occurring in a “Wet” and “Dry” form. These terms are sometimes confusing because they have no relationship to whether your eye waters or how the eye feels. What they refer to are the changes present inside the eye – which are either of a slow loss of tissue (so could be imagined as things “drying” out), or of sudden worsening that involves swelling and hemorrhage in the retina, things that can be described as “wet”.
Where is the macula?
The macula is located in the centre of the retina, the light-sensitive tissue at the back of the eye. The retina instantly converts light, or an image, into electrical impulses. The retina then sends these impulses, or nerve signals, to the brain.
What are the symptoms
For dry ARMD: the most common early sign is blurred vision, such as difficulty reading. As fewer cells in the macula are able to function, people will see details less clearly in front of them, such as faces or words in a book.
For wet ARMD: the classic early symptom is that straight lines appear crooked, where previously they had been normal. This results when fluid from the leaking blood vessels gathers and lifts the macula, distorting vision. A small blind spot may also appear in wet AMD, resulting in loss of one's central vision.
How is macular degeneration diagnosed?
Examination of the retina is done by an eye surgeon, after enlarging (dilating) the pupil with drops. Usually an Ocular Coherent Tomography (OCT) scan is also performed, which is like a very fine detail picture taken through the retina. The picture (normal OCT.jpg above) on the right shows the usual structure of the retina, with the bright orange layer being the tissue on it’s outer surface. On the left is an OCT image showing the swelling (increased thickness) of a macula with ‘wet’ ARMD, the darker spaces among the green (nerve tissue) representing collections of fluid.
Some people also require a test known as a Fluorescein Angiogram, which is a series of special photos taken of the retina as a fluorescent dye is injected through a patient’s blood circulation. This shows area of abnormal blood vessels and leakage.
When should I be seen?
Anyone over 50 years of age with a sudden change in their central vision should be seen promptly, especially if they have lost vision in their other eye from macular degeneration, or are known to be at risk. An initial visit for retinal photography by one of our technicians can be arranged at relatively short notice, and the pictures taken then will help Dr Bedggood determine when you should be seen and whether treatment is likely to be required.
Urgent treatment of macular degeneration is necessary for the ‘wet’ form, as without this it continues to worsen in the majority of cases until only limited central vision remains in the eye. New drugs, which need to be injected into the eye, are able prevent this severe loss of central vision, and in many cases to regain early losses as well.