Macular Degeneration

Macular Degeneration

Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss in Australians aged 50 or older.

What is AMD?

Age-related macular degeneration affects the macula, a small central area located at the back of the eye. The macular is responsible for providing detailed, “straight-ahead” vision, and AMD gradually blurs the central vision required for activities like reading and driving. AMD is thought to be caused by oxidative stress and accumulation of waste products generated by metabolic processes within the retina.

AMD does not cause total blindness, but it does interfere with many activities of daily living and can severely affect quality of life.

There are two types of AMD: wet AMD and dry AMD.

Causes and symptoms

In dry AMD, there is a gradual breakdown of the light-sensitive photoreceptors located at the macula. Dry AMD tends to progress gradually and usually both eyes are affected.

Symptoms of dry AMD include:

  • Need for increased light when reading or doing close work
  • Difficulty adjusting to low light levels
  • Increased blur when reading
  • Reduced intensity or brightness of colours
  • Difficulty recognising faces

Most people with dry AMD will experience minimal or no loss of vision. However, dry AMD can potentially cause vision loss by either turning into wet AMD, or by causing progressive and extensive destruction of the photoreceptors (known as geographic atrophy). Unfortunately there is no way to tell if or when the dry form will turn into the wet form.

In wet AMD, abnormal blood vessels start to grow under the macula. These new blood vessels are very fragile and leak blood and fluid. Unlike dry AMD, damage to the macula and loss of central vision will occur rapidly in wet AMD. Wet AMD is a treatable condition but early detection is critical for stabilising vision.

Symptoms of wet AMD include:

  • Distortion of printed words
  • Distortion of straight lines (which often appear wavy), most clearly picked up with an Amsler grid

If you are at risk of AMD, it is important to be aware that a new onset of blurred vision or distorted vision may be an early warning sign, and that vision may deteriorate unless urgent action is taken.

Detection and diagnosis

Eye examinations and regular screenings with your eye care practitioner will detect the early signs of AMD. Testing may include:

  • Visual acuity: a measurement of vision on a letter chart
  • Amsler grid: assessment of central distortion such as lines being faded, broken or wavy
  • Retinal examination: examination of the macula is usually done through a dilated/enlarged pupil. In early dry AMD, there will often be small yellow spots at the macula (drusen), which represent the accumulation of metabolic waste products.

Testing may also include optical coherence tomography, which can identify areas of macular thickening or thinning and the presence of abnormal blood and fluid under the macula, or fluorescein angiography, which is essential in diagnosing or excluding wet AMD.

Treatment

There is currently no treatment available for dry AMD. However, your eye care practitioner may recommend the use of formulated antioxidant and nutritional supplements, which large studies have been shown to reduce the risk of developing wet AMD.

Lifestyle and dietary changes may help prevent early dry AMD, including:

  • Eating a well-balanced diet, incorporating green leafy vegetables daily and fish two to three times a week
  • Maintaining a healthy weight and blood pressure
  • Exercising regularly
  • Quitting smoking

If you have dry AMD it is also recommended that you use an Amsler grid for self-monitoring of new blur or distortion that would warrant prompt investigation by your retinal specialist.

In the majority of cases wet AMD can successfully be treated with anti-VEGF medication, which stops the new abnormal blood vessels from growing and leaking. The eye is numbed using local anaesthetic before the anti-VEGF agents are injected (a procedure that involves minimal discomfort). Induction therapy of three injections is initially required to stabilise wet AMD, with maintenance therapy typically required every 4 to 12 weeks thereafter to maintain vision.

With treatment there is a 90-95% likelihood of stabilising vision and preventing further decline. The earlier this is initiated the better the vision outcome is likely to be.

The majority of people suffering from early wet AMD are able to lead independent lives, with the ability to continue driving and reading.

Living with AMD – what do I need to be aware of?

Transport

  • Check with your doctor if driving is still safe and legal
  • Abide by restrictions (e.g. avoid driving at night/in bad weather)

Home & Leisure

  • Ensure your spectacles contain the best possible prescription
  • Read large print books and magazines
  • Ensure there is plenty of light when reading
  • Magnify print on the computer
  • Use specialised hand and stand magnifiers
  • Obtain specialised appliances with large numbers and displays (e.g. clock faces and telephone number pads)
  • Remove hazards at home that may cause falls or injuries

Resources and support

  • Macular Degeneration Foundation:

    Ph: 1800 111 709

    Site: www.mdfoundation.com.au

  • Vision Australia: 37 Kent St, WOOLLOONGABBA QLD 4102

    Ph: 1300 847 46

    Site: www.visionaustralia.org.au

  • LifeTec QLD: Level 1 Reading Newmarket, Newmarket Rd,

    NEWMARKET QLD 4051

    Ph: 1300 885 886 Site: www.lifetec.org.au

There has been research in recent years examining the link between the use of aspirin and AMD. It is currently believed that aspirin has no effect on early AMD. There may be a possible association between aspirin use and progression of moderate and high risk AMD, however, the evidence behind this remains fairly limited.

We recommend that AMD patients who are taking aspirin on the instruction of their general practitioner should continue to do so, and close monitoring of the maculae is advisable in cases of moderate and advanced AMD. Patients should always consult their general practitioner before starting aspirin use.

Yes. Dry AMD can potentially cause vision loss by either turning into wet AMD or by causing progressive and extensive destruction of the photoreceptors (known as geographic atrophy). There is no way to tell if or when the dry form will turn into the wet form.

Eye Examination Regular screening examinations with your eyecare practitioner will allow early signs of AMD to be detected. Testing may include:

  • Visual acuity: a measurement of vision on a letter chart
  • Amsler grid: assessment of central distortion such as lines being faded, broken or wavy
  • Retinal examination: examination of the macula is usually done through a dilated/enlarged pupil. In early dry AMD, there will often be small yellow spots at the macula (drusen) which represent the accumulation of metabolic waste products

Optical Coherence Tomography (OCT)
Optical coherence tomography (OCT) allows non-invasive imaging of the macula in cross-section. It can identify areas of macular thickening or thinning, as well as detect the presence of abnormal blood and fluid under the macula, as seen in wet AMD. OCT is also helpful in monitoring the response of wet AMD to treatment.

Fluorescein Angiography
In fluorescein angiography, fluorescein dye is injected into a vein in the arm which then travels to the eye. A series of photographs are taken as the dye passes through the blood vessels in the retina.

The abnormal leaky blood vessels that form in wet AMD will appear as a white patch. Fluorescein angiography is essential in diagnosing or excluding wet AMD. It will also detect subtle changes in macular pigment due to dry AMD changes.

Transport

  • check with your doctor if driving is still safe and legal
  • abide by restrictions (eg. avoid driving at night/in bad weather)
  • use public transportation, local area transport services or volunteer driving networks where possible
  • ask family members and friend to help with transport

Home & Leisure

  • ensure your spectacles contain the best possible prescription
  • read large print books and magazines
  • ensure there is plenty of light when reading
  • magnify print on the computer
  • use specialised hand and stand magnifiers*
  • obtain specialised appliances with large numbers and displays (eg. clock faces and telephone number pads)*
  • remove hazards at home that may cause falls or injuries*
  • *see below for support networks who can offer/organise these services

Social Support

  • ask family and friends for help and support
  • ask Vision Retinal Institute staff for help accessing services
  • take advantage of community and online networks that can offer support and resources for people with AMD
  • Vision Australia: 37 Kent St, WOOLLOONGABBA QLD 4102
    Ph: 1300 847 46
    Site: www.visionaustralia.org.au
  • LifeTec QLD: Level 1 Reading Newmarket, Newmarket Rd,
    NEWMARKET QLD 4051
    Ph: 1300 885 886 Site: www.lifetec.org.au
  • Macular Degeneration Foundation:
    Ph: 1800 111 709 Site: www.mdfoundation.com.au

Age-related macular degeneration (AMD) is a disease that affects the macula and blurs the central vision. Damage from AMD is thought to be due to oxidative stress and accumulation of waste products generated by metabolic processes within the retina.

AMD generally affects people aged 50 years and older, and it is the most common cause of irreversible vision loss in this age group. AMD does not cause total blindness but it does interfere with many activities of daily living and can severely affect quality of life.

There are two main types of age-related macular degeneration: dry AMD and wet AMD:

Dry age-related macular degeneration:

In dry AMD, there is a gradual breakdown of the light-sensitive photoreceptors located at the macula. Dry AMD tends to progress gradually and usually both eyes are affected.

Symptoms of dry AMD include:

  • need for increased light when reading or doing close work
  • difficulty adjusting to low light levels
  • increased blur when reading
  • reduced intensity or brightness of colours
  • difficulty recognising faces

Wet age-related macular degeneration:

In wet AMD, abnormal blood vessels start to grow under the macula. These new blood vessels are very fragile and will leak blood and fluid. Unlike dry AMD, damage to the macula and loss of central vision will occur rapidly in wet AMD. Wet AMD is a treatable condition but early detection is critical for stabilising vision.

Symptoms of wet AMD include:

  • distortion of printed words
  • distortion of straight lines (often will appear wavy), most clearly picked up with an Amsler grid

If you notice any sudden distortion in your vision, contact your eyecare practitioner immediately

The macula is a small area (5mm in size) located in the very central part of the back of the eye (the retina). The macula contains a higher concentration of photoreceptors (cells which absorb light and transfer the information to the brain for visual interpretation) than the rest of the retina

The macula is responsible for providing sharp central vision as well as recognition of colours. We use our macula for all “straight-ahead” tasks such as driving, reading and recognising faces. The rest of the retina is used in peripheral, or side, vision.

There is currently no cure for dry AMD, and once vision has been lost it cannot be restored. Lifestyle and dietary changes may help prevent early dry AMD:

  • eating a well-balanced diet (incorporate green leafy vegetables daily and fish two to three times a week)
  • maintaining a healthy weight and blood pressure
  • exercising regularly
  • cease smoking

For moderate and advanced dry AMD, treatment with anti-oxidant supplements can slow and/or prevent vision loss. The Age-Related Eye Disease Study (AREDS) found that specific high-dose formulations of anti-oxidant vitamins such as Macuvision significantly reduced the risk of AMD progression and vision loss in high-risk patients. Lutein supplements (eg. Lutein Vision) have also recently been found to have protective effect on the macula. These tablets will not restore vision that has already been lost and does not benefit those with no or mild AMD.

Macutec is an AREDS formulation that also incorporates lutein, zinc and omega-3 fatty acids (fish oil). Taken 3 times a day, it contains:

  • 500mg Vitamin C
  • 400iu Vitamin E
  • 50mg zinc oxide
  • 10mg lutein
  • 2mg zeaxanthin
  • 1666mg omega-3

You should discuss taking anti-oxidant vitamins with your general practitioner before you start taking the tablets. This is particularly important if you take other medications or have other medical conditions. Side effects from AREDS supplements are uncommon but can occur, as with any medical treatment.

These include:

  • a small risk of urinary conditions (primarily urinary obstruction related to prostate enlargement) – consult your general practitioner or urologist before starting treatment
  • nausea
  • indigestion
  • skin rash

AREDS vitamins are not known to increase the risk of serious conditions such as heart attack, stroke or cancer.

The current treatment for wet AMD is anti-VEGF therapy. VEGF is the chemical in the body responsible for the formation of abnormal leaky vessels in wet AMD. There are several anti-VEGF drugs currently available, including Eylea, Lucentis and Avastin. Eylea and Lucentis are PBS-approved for specific cases of wet AMD. Avastin is a very similar drug but was not originally developed for use in the eye. It can be used as an “off-label” agent if government funding is not applicable.

Anti-VEGF agents are injected into the eye after the eye has been completely numbed with local anaesthetic. Three injections are initially required to stabilise the wet AMD – this is known as Induction Therapy. Maintenance Therapy will be usually required every 4 to 12 weeks thereafter to maintain vision.

Anti-VEGF treatment can stabilise and prevent further vision decline in 95% of patients. It may even result in an improvement in vision in 40% of patients. However, wet AMD may sometimes continue to progress despite treatment.

Anyone can develop macular degeneration but a number of factors place you at greater-than-average risk:

Controllable risk factors for AMD:

  • Smoking: smokers have a 6x greater risk of developing AMD
  • Nutrition: diets high in lutein and omega-3 fatty acids (fish) can reduce the risk of AMD
  • Obesity: being severely overweight increases the chances of early AMD progressing to severe AMD
  • Cardiovascular Disease/High Blood Pressure
  • Sun Exposure: excessive UV exposure increases the risk of AMD

Uncontrollable risk factors for AMD:

  • Age
  • Genetics: specific genes have been associated with increased AMD risk. The risk of developing late stage AMD is 4x higher for people with a family history of AMD.
  • Gender: females are more at risk of AMD than males
  • Light skin/eye colour: people with fairer complexions are more at risk of AMD than those with darker-skinned individuals
  • High long-sightedness