Age-Related Macular Degeneration (known as AMD) is the major cause of legal blindness in Australia, affecting as many as one in seven people over the age of 50.
In recent years there have been significant breakthroughs aiding the diagnosis and treatment of AMD, and research is continuing into improved treatment options that will become available in the very near future.
What is Age Related Macular Degeneration (AMD)?
Macular Degeneration starts with small yellow spots (called Drusen) on the central retina.
AMD is a degenerative disease of the retina (the back part of the eye that acts like a film in a camera), which affects the macula (the central part of the retina). The macula is the area of the retina responsible for your central vision, used for reading, perceiving fine detail and recognising faces.
AMD begins in the retinal pigment epithelium (RPE) the area of the retina that is like a two way channel, transferring oxygen, sugars and other essential minerals from underlying blood vessels (choroid) to the retina and at the same time sending waste from the retina to the choroid.
In the early stage of the disease there is an accumulation of waste deposits between the retina and the choroid. This early stage may not cause visual disturbance, but does lead to an increased chance of developing Wet or Dry (late stage) AMD.
This clumping of waste deposits, causes cells in the RPE layer break down causing the loss of central vision. When cells in this RPE layer die, little blood vessels from the choroid can grow through these gaps in the layer. These blood vessels are very fragile and often leak into the retina causing a further decrease in central vision.
About Wet and Dry AMD
Dry AMD causes a gradual decrease in vision due to cells of the retina (retinal pigment epithelium) progressively dying, leading to patches of missing retina. Dry AMD can always become wet AMD, so monitoring the condition with the Amsler Grid is important to monitor the condition.
Wet AMD causes a more sudden change in vision, from an increase in distortion (bending of straight lines) to a rapid loss of central vision if left untreated. This change is caused by new, abnormal blood vessels growing through the gaps in the retina. These blood vessel walls are very weak and leak blood into the retina and lead to scarring of the retina. With early intervention, in the form of Lucentis injections, this undesirable outcome can be avoided and a patient’s vision can be saved from this rapid decline.
In wet Macular Degeneration, fluid accumulates under the macula, causing the macula to swell.
Frequently Asked Questions
What are the symptoms?
- Increased difficulty with reading, especially in low light irrespective of change to glasses prescription.
- Change in colour perception.
- Dark patches/shadows in the vision.
- Distortion eg when bathroom tiles don’t appear square, street poles appear bent.
What are the risk factors?
- Smoking: 3 times more likely to be affected.
- Family History: There is a 50% increase in chance of developing AMD with a family history of the disease.
- Age: 1 in 7 people over the age of 50 have this condition and the risk increases with increasing age.
- Sex: Females have a higher risk of AMD than males.
If untreated, will I go blind?
Untreated wet AMD has a fairly rapid progression. If left untreated, legal blindness results in around 12 months. There is no effective treatment for dry AMD, however this type of AMD has a much slower progression than wet AMD.
How is Wet Macular Degeneration Treated?
If your AMD is wet, there is a medication called Lucentis which is injected into the vitreous (the jelly part of the eye). This medication stops the abnormal blood vessels from growing in the first place, preventing further deterioration to vision.
Unfortunately, however, this medication only stays present in the eye for around one month, which means that repeated monthly injections are required. After the first 3 injections, your ophthalmologist can determine if the period between these injections can be increased depending on the response that your eye has to treatment.
An Injection into the eye sounds painful, is it?
While this does sound painful, it doesn't need to be. Our clinic uses a technique which involves two stages of anaesthetic to prevent discomfort.
Prior to the injection, you will receive 2 different types of anaesthetic, one in the form of drops and the other in a small injection underneath the conjunctiva (the thin, clear covering over the white part of your eye). The combination of both anaesthetics is used to eliminate as much pain from the injection as possible. Some patients describe the feeling of slight pressure, but most do not have pain.