What is aged-related macular degeneration (AMD)?

What is it: Age-related macular degeneration (AMD) is a chronic, painless eye disease associated with ageing that affects the macula, leading to central vision loss.

Your macula is a small oval shaped area, only about 5.5 mm in diameter big, in the centre part of your retina at the back of the eye. Your macula is responsible for your sharp central vision and most of your colour vision. It is used for seeing the fine detail of objects, for example, when looking at images, reading, watching television, or driving.

According to the Centre for Eye Research Australia, AMD is one of the leading causes of vision loss in Australia, and it is most common in those aged over 50. It is estimated that one in seven Australians over the age of 50 have signs of AMD, although not all people will go on to experience serious vision loss.

Types of AMD: There are two types of AMD:

Dry AMD is caused by the gradual degeneration or dying of the cells in the macula, causing it to get thinner. Dry AMD is quite common and usually less aggressive with a slow, more gradual progression of vision loss.

Wet AMD is caused by the growth of abnormal blood vessels in the retina which cause fluid leakage and can interfere with vision, damage the macula and cause more rapid and severe vision loss.

Symptoms: AMD causes blurred vision and loss of vision in the middle of what you would normally see. This could include losing the ability to see fine details, whether you are looking at something close or far, making it hard to read, see people’s faces, or drive. But your peripheral (side) vision will still be normal. For instance, imagine you are looking at a clock with hands. With AMD, you might see the clock’s numbers but not the hands.

In its early stages, you may not notice changes to your vision, which is why regular eye tests are essential. You should never assume that vision changes are just part of getting older; AMD is not a normal or predetermined consequence of aging. See an optometrist or ophthalmologist as soon as possible if you notice any changes in your vision.

The earlier you’re diagnosed, the better.

Some of the signs and symptoms of AMD include:

• Blurry vision and a gradual or sudden loss in your ability to see things clearly.
• Distorted vision, such as straight lines appearing wavy or bent.
• Dark or missing spots in your central vision.
• Difficulty reading, driving, or recognising faces despite wearing glasses.
• Disturbance to colour perception.
• Needing brighter light to read.
• Decreased night vision.

Causes: Although the exact causes of AMD are still being discovered, there are risk factors that can increase your likelihood of developing AMD, including:

• Your age: your risk increases the older you get.
• Genetics: family history may make you at higher risk of developing AMD.
• Smoking.
• Having heart disease and high cholesterol levels may also put you at higher risk.
• Some new evidence uncovered by the Macular Disease Foundation suggests more than approximately one standard drink per day was likely associated with higher risk of developing early AMD.

Reducing the risk of AMD: Although there is no cure for AMD, there are some ways that you can reduce your risk of developing AMD, including:

• Eating a nutrient-rich diet with lots of dark, leafy greens, yellow fruits and vegetables, and healthy omega-3 fats which can be found in fish or walnuts.
• Avoiding or quitting smoking.
• Limit alcohol intake.
• Protecting your eyes from the sun.
• Having regular eye tests.
• Letting your relatives know about their family history so they too can monitor for early signs of AMD.
• Maintaining a healthy lifestyle through regular exercise and keeping your blood pressure and cholesterol under control.

Diagnosis: Your eye care professional will conduct an examination of your eyes which may include:

• Checking your visual acuity, which is your ability to see detail at different distances. This can include recognising letters at varying distances.
• Assessing your peripheral vision with a visual field test, which is your ability to see in your side vision.
• Checking your retina at the back of your eye with an ophthalmoscope by shining a light into your eye and looking through different lenses or using an optical coherence tomography scan (OCT) which creates a 3D cross section image to see the layers in the retina or take a digital colour photo of the retina.
• Checking the surface of your eye and other structures within the eye with a microscope called a slit lamp.
• Measuring the pressure in your eyes.

If your eye care professional sees signs of AMD or diagnoses you with AMD, it is crucial to have regular eye tests to ensure your condition is managed appropriately with the goal of minimising future vision loss.

Treatment: There is no cure for AMD but there are treatments for wet AMD to try to prevent it from getting worse. These include anti-VEGF injections that can help to prevent the growth of abnormal blood vessels and stop blood and fluid leakages. Read this article to learn more about Anti-VEGF injection.

In some cases, although not often, laser surgery might also be used in conjunction with anti-VEGF injections to treat certain types of wet AMD.

Currently there is no treatment for dry AMD, however, a healthy diet and regular exercise can slow progression. Some eye care practitioners may recommend certain vitamin supplements. Speak to your eye care practitioner to find out what is best for you. Dry AMD can sometimes develop into wet AMD, which is why it’s important to monitor for any changes in your vision and have regular eye tests.

Making the most of the vision you have: If you have AMD, you can learn how to make the most of your vision. Often you can still do many of your favourite things with special low vision tools. These can include different kinds of magnifying tools, handheld computers, and electronic devices such as your smart phone or tablet and more.

Read this article to learn more about low vision aids or this article to learn how to modify your handheld digital devices.

You can also learn how to use your side vision to help you do things. An orthoptist can teach you how this works. They also can help you find many low vision support services and tools. You can also read our article on eccentric viewing, which has strategies for you to practise using your peripheral vision.

Ask your eye care professional to help you find a low vision orthoptist in your area.

The goal is to learn new ways to be as independent as possible.

For more information

• Visit Macular Disease Foundation.
• Talk to your eye care professional.

Always speak to your GP and eye care professional about the best treatment options for you.

Self-monitoring of AMD: People at risk of developing AMD or have early signs of AMD may use tools like an Amsler grid to monitor any changes in their central vision.

An Amsler grid is typically a printed card with a grid pattern on it, given to patients to take home. Patients are instructed to view the card with their reading glasses on, with one eye at a time and holding it 30 cm from their face. Whilst viewing the card with one eye, the patient is asked to look directly at the dot in the middle of the grid and to note if they notice any changes in their vision since they last viewed it such as any new blurriness, wavy or bent lines, or dark or blank or out of shape areas within the grid. If any changes are noted, the patient should make an urgent appointment with their eye care professional. Individuals with AMD should use an Amsler grid as recommended by their eye care professional.