Age Related Macular Degeneration

What is the macula?

The macula is part of the retina at the back of the eye. It is only about 5mm across but is responsible for our central vision, most of our colour vision and the fine detail of what we see. The macula has a very high concentration of photoreceptor cells – the cells that detect light. They send signals to the brain, which interprets them as images. The rest of the retina processes our peripheral, or side vision.

What is the macula?

The macula is part of the retina at the back of the eye. It is only about 5mm across but is responsible for our central vision, most of our colour vision and the fine detail of what we see. The macula has a very high concentration of photoreceptor cells – the cells that detect light. They send signals to the brain, which interprets them as images. The rest of the retina processes our peripheral, or side vision.

What is age-related macular degeneration?

There are many forms of macular disease, including age-related macular degeneration or AMD. This usually affects people over 60 but can happen earlier. In the UK around 600,000 people are affected by AMD – the most common cause of sight loss in the developed world. About half are registered as visually impaired.

The older we are the greater our risk of developing the condition. Around one in every 200 people has AMD at 60. However by the age of 90 it affects one person in five. We are all living longer so the number of people affected is increasing.

There are two forms of AMD – dry and wet. Dry AMD is a gradual deterioration of the macula as the retinal cells die off and are not renewed. The term dry does not mean the person has dry eyes, just that the condition is not wet AMD. There is currently no treatment for dry AMD. The progression of dry AMD varies but in most Macular Society people it develops over many months or years. Often people carry on as normal for some time.

Wet macular degeneration develops when abnormal blood vessels grow into the macula. These leak blood or fluid which leads to scarring of the macula and rapid loss of central vision. Wet AMD can develop very suddenly. It can now be treated if caught quickly.

Fast referral to a hospital specialist is essential.

Around 10 to 15 per cent of people with dry AMD develop wet AMD so if you have been diagnosed with the dry form of the disease and notice a sudden change in your vision, contact your optometrist or hospital eye specialist urgently. If you have AMD in one eye, the other eye may be affected within a few years.

Other forms of macular disease include genetic conditions, which affect young people. See our booklet Juvenile macular dystrophies

Symptoms

Macular degeneration affects people in different ways. Symptoms may develop slowly if you have dry AMD, especially if it’s only in one eye. However, as the condition progresses, your ability to see clearly will change.

• Gaps or dark spots (like a smudge on glasses) may appear in your vision, especially first thing in the morning.
• Objects in front of you might change shape, size or colour or seem to move or disappear.
• Colours can fade.
• You may find bright light glaring and uncomfortable or find it difficult to adapt when moving from dark to light environments.
• Words might disappear when you are reading.
• Straight lines such as door frames and lampposts may appear distorted or bent.

Diagnosing AMD

The optometrist at your local optician’s practice can test sight, prescribe glasses and check for eye disease. Some optometrists use photography or other imaging to detect early signs of macular degeneration. These might include Optical Coherence Tomography (OCT) scans which create cross-sectional images of the retina. You may be charged for these tests.

There is currently no treatment available for dry AMD so you might not be referred to hospital, unless confirmation of the diagnosis is required or the optometrist thinks you need a hospital low vision service. If your sight has worsened and you would like to be registered as sight impaired you will need a hospital appointment.

If your optometrist suspects you have wet AMD you should be referred to a retinal specialist at a hospital directly and seen within one to two weeks and if applicable be treated within two weeks after initial identification. You should not be sent to your GP. This causes unnecessary delay.

At hospital further tests will confirm the diagnosis. The specialist may use:

• Eye drops to dilate the pupils to see the back of the eye clearly. These may make your vision blurred and sensitive to light for a short time so consider taking someone with you.
• OCT scans.
• Fluorescein dye angiography. A dye injected into a vein in the arm travels to the eye, highlighting the blood vessels in the retina so they can be photographed. The dye will temporarily change the colour of your urine, so be prepared.

Treating AMD

Wet AMD can be treated if caught early. Drugs are injected into the eye to stop the growth of the abnormal blood vessels. Following diagnosis people will usually have a loading dose of three injections, once a month for three months. A patient will then be assessed to see if more are required.

The injections are not as bad as they might sound. The patient’s eye is anaesthetised and the needle goes into the corner of the eye so the patient does not see it.

Some people do not respond to the injections and may be offered a form of laser treatment instead. There are a range of treatments and options although not all are available on the NHS.

Further information is available on the Macular Society website.

https://www.macularsociety.org

Disclaimer

Devon in Sight is not a medical organisation, therefore we can only provide general information that is not intended to be a substitute for a proper medical assessment. The information is also not intended to be used for individual cases. If you have a specific question about your eye condition, we recommend that you consult an eye care professional.

Devon in Sight has tried to ensure that the contents of these pages are accurate. However Devon in Sight will not accept liability for any loss or damage or inconvenience arising as a consequence of any use of or the inability to use any information on our website or in these fact sheets.

Visitors who use our website and use these factsheets and rely on any information do so at their own risk. Devon in Sight does not represent or warrant that the information accessible via the website or these fact sheets is accurate, complete or up to date.

The information contained on the website or these factsheets was correct at the time of writing. However, due to research and medical advances, the content may not be completely up to date.