Macular Degeneration

Macular Degeneration

Sight is a precious sense. Vision is the way we access, appreciate and interpret the world. We need to look after and protect our eyes, especially as we grow older. It is therefore important to be aware of macular degeneration, the leading cause of blindness and severe vision loss in Australia.

But, what is macular degeneration and how do we look after our macular health? Optical by National Pharmacies Optometrist, John Altmann, answers these questions in the video below and read on for more information about macular health from the Macular Disease Foundation.

The eye works very much like an old-style film camera. The front of the eye, comprising the cornea, iris, pupil and lens, focuses the image onto the retina, which lines the back of the eye. The retina is sensitive to light and acts like the film in the camera, capturing images and then sending them via the optic nerve to the brain, where the images are interpreted.

What is the Macular?

The macular is the name given to the area at the very centre of the retina. This region is responsible for detailed central vision and most colour vision.

It is responsible for the ability to read, recognise faces, drive a car, see colours clearly and any other activity that requires fine vision. The rest of the retina is called the peripheral retina. lt is used to see general shapes and provides ‘get-about’ vision, which is also called side vision or peripheral vision.

What is Macular Degeneration

Macular degeneration is the name given to a group of chronic, degenerative retinal eye diseases that cause progressive loss of central vision, leaving the peripheral or side vision intact.

Macular degeneration is usually related to ageing and most frequently affects people over 50 years of age. lt is commonly referred to as age-related macular degeneration or AMD. However, it is not a normal or inevitable consequence of ageing. Certain forms of the disease can also affect younger people.

Macular degeneration is progressive and painless and although it can lead to legal blindness, it does not result in total or ‘black’ blindness.

How common is Macular Degeneration?

About one in seven Australians (1 million people) over the age of 50 has some evidence of macular degeneration. Approximately 17% of these people (170,000 Australians) experience vision impairment. It is the leading cause of legal blindness in Australia and is responsible for 50% of all cases of blindness.

What happens in Macular Degeneration?

Macular degeneration is a disease that affects a special layer of cells in the eye called the retinal pigment epithelium (RPE).

The RPE is like a wall that separates the retina from its main blood supply, a vascular layer called the choroid. The major role of the RPE is to nourish the retina and get rid of its waste products. The RPE also acts as a barrier between the choroid and the retina.

As macular degeneration progresses, these waste products from the retina build up underneath the RPE forming yellow spots called drusen.

It is possible to have these first signs of macular degeneration called drusen without knowing and that is why it is so important to have an eye test and the macular checked. An Optometrist or an eye specialist can examine the eyes for the early signs of the disease (drusen) by looking inside the back of the eye using special optometric equipment.

Small amounts of drusen do not necessarily cause visual symptoms. Also not everyone with drusen will inevitably lose vision. However, the existence of drusen does increase the chance of developing late stage macular degeneration.

Loss of vision represents the later stage of the disease and occurs because the RPE cells die, or because they fail to keep blood vessels from the choroid from growing under the retina.

When RPE cells die, the retinal cells above them also die, leading to patches of ‘missing’ retina. This is commonly called geographic atrophy or ‘dry’ macular degeneration. This is a slow form of the disease causing a gradual loss of vision. lt accounts for 33% of all cases of late-stage macular degeneration. Some people who have either the early or the dry form can later develop the more aggressive wet form. lt is therefore important for any sudden changes in vision to be reported to an eye specialist as a matter of urgency. Any delay in treatment can risk vision loss.

Wet macular degeneration occurs when the RPE cells fail to stop choroidal blood vessels from growing under the retina. This growth is called choroidal neovascularisation (CNV). The rapidly growing vessels are fragile with leaky walls and they ooze fluid and blood under the retina, leading to scarring and vision loss. This is the most severe form of the disease with approximately 21,000 new cases diagnosed annually in Australia. Vision changes are often sudden and severe.

What causes Macular Degeneration?

Macular degeneration is caused by genetic and environmental factors. Risk factors include age, family history, smoking, diet and lifestyle. One in seven Australians over the age of 50 has some evidence of the disease, and the incidence increases with age. lt can also be hereditary, with a 50% chance of developing it if there is a direct family history. Since at least 70% of cases have a genetic link, it is critical that people with macular degeneration inform their siblings and children, and encourage them to have their eyes tested and macula checked.

Studies have shown that those who smoke are three to four times more likely to develop macular degeneration, and smokers may also develop the disease five to ten years earlier than non-smokers. Those with a specific genetic predisposition who smoke have a significantly increased risk of developing wet macular degeneration.

Preventing Macular Degeneration

Although family history and age cannot be changed, the following can help to reduce the risk of developing macular degeneration:

• Have an eye test and make sure the macula is checked
• Don’t smoke
• Keep a healthy lifestyle, control weight and exercise regularly
• Eat a healthy, well-balanced diet
• Eat fish two to three times a week, dark green leafy vegetables and fresh fruit daily, and a handful of nuts a week. Limit the intake of fats and oils.
• Choose low glycemic index (Gl) carbohydrates instead of high GI whenever possible
• ln consultation with a doctor, consider a suitable supplement
• Use an Amsler grid daily to check for symptoms of macular degeneration
• Provide adequate protection for your eyes from sunlight exposure. including for those who are very young

How do you know if you have Macular Degeneration?

You can have the early signs of macular degeneration (drusen) without knowing and that is why it is so important to have an eye test and macula check. During the early stages, symptoms will typically not be noticed.

As the disease progresses, symptoms can include one or more of the following:

• Difficulty in reading or any other activity which requires fine vision
• Distortion, where straight lines may appear wavy or bent
• Distinguishing faces becomes a problem
• Dark patches or empty spaces appear in the centre of your vision

The need for increased illumination, sensitivity to glare, decreased night vision and poor colour sensitivity may also indicate that there is something wrong.

Any changes in vision should never be dismissed as just part of getting older. For both wet and dry macular degeneration the earlier a diagnosis is made the earlier that steps can be taken to slow disease progression with wet macular degeneration, the earlier the treatment is started, the greater the likelihood of saving sight.

It is essential to have an eye test and a macula check by an eye care professional with regular follow-up according to their recommendation.

lf any sudden changes in vision occur or any symptoms are noticed, see an eye specialist without delay (within a week).

Early detection and prompt intervention are crucial to saving sight.

This article was supplied by The Macular Disease Foundation Australia.