Macular Degeneration (MD)
What is the macula?
The macula is the name given ti 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 your ability to read, recognise faces, drive a car, see colours clearly and any other activity that requires fine vision. The rest on the retina is called the peripheral retina. It is used to see general shapes and gives you your ‘get-about’ vision, which is also called side vision or peripheral vision.
What is Macular Degeneration?
Macular Degeneration (MD) is the nam given to a group of degenerative retinal eve 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 fifty years of age. It is commonly referred as Age-related Macular Degeneration or AMD. However, it is important to remember that inherited forms of the disease can also affect young people. Age-related Macular Degeneration is progressive and painless. it never leads to total or black blindness.
What happens in Age-related Macular Degeneration?
- Age-related Macular Degeneration is not a natural consequence of ageing. It is a disease that affects a special layer of cells in the eye called the Retinal Pigment Epithelium. The Retinal Pigment Epithelium is like a wall that separates the retina from its main blood supply, a vascular layer called the choroid. The major role of the Retinal Pigment Epithelium is to nourish the retina and get rid of its waste products. The Retinal Pigment Epithelium also acts as a barrier between the choroid and the retina.
- Early Stage Age-related Macular Degeneration: As Age-Related Macular Degeneration progresses these waste products from the retina build up underneath the Retina Pigment Epithelium. When the Doctor looks at the back of the eye, he or she may see these deposits as yellows spots called Drusen. These early signs do not necessarily cause visual symptoms. However, they do increase the chance of Age-related Macular Degeneration associated vision lost.
- Late Stage Age-related Macular Degeneration: Loss of vision represents the late stage of the disease and occurs because the Retinal Pigment Epithelium cells die, or because they fail to keep the blood vessels from the choroid out of the retina. When the Retinal Pigment Epithelium cells die, the retinal cells above them also die, leading to patches of ‘missing’ retina. This is commonly called geographic atrophy or dry Age-related Macular Degeneration.
Dry Age-related Macular Degeneration is a slow form of the disease causing a gradual loss of vision. It accounts for thirty-three percent of all cases of late stage of Age-related Macular Degeneration. Some patients who have dry Age-related Macular Degeneration can later develop the more aggressive wet form.
If you experience any sudden change in vision you should see your specialist urgently.
Wet Age-related Macular Degeneration occurs when the Retinal Pigment Epithelium cells fail to stop choroidal blood vessels from growing into the retina. This growth is called Choroidal Neovascularisation. The rapidly growing vessels are fragile with leaky walls and they ooze fluid and blood into the retina, leading to scarring and vision loss.
Wet Age-related Macular Degeneration is the most severe form of the disease with approximately 17,000 new cases diagnosed annually in Australia. Vision changes associated with the wet form are often sudden and severe.
If you experience any sudden change in vision you should see your eye specialist urgently as early detection is crucial.
The earlier you seek treatment, the more likely you are to have a better outcome, compared to those you wait.
What cause Macular Degeneration?
Macular Degeneration affects 1 in 7 Australians over the age of fifty and the incidence increases with age. It is hereditary, with a fifty percent chance of developing Macular Degeneration if a family history of the disease is present. Macular Degeneration is caused by genetic and environmental factors. Risk factors include age, family history, smoking and diet and lifestyles factors.
How do I know if I might have Macular Degeneration?
Key symptoms can include one or more of the following:
- Distortion, where straight lines may appear wavy or bent
- Difficulty in reading or any other activity which requires fine vision
- 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.
These symptoms should not be dismissed as part of just getting older.
Remember, the earlier the treatment is sought, the greater likelihood of a better outcome compared to people who wait.