What is it?
What is Age-related Macular Degeneration?
Age-related macular degeneration (AMD) is an aging process that can seriously affect the central vision - in fact, it is the most common cause of legal blindness in Australia. The macula is the part of the retina responsible for fine vision (reading, watching TV, and recognising faces). AMD typically occurs in people over the age of 50.
Age related macular degeneration can be classified into 2 forms:
- Dry age related macular degeneration (dry AMD)
- Wet Age related macular degeneration (wet AMD)
Dry AMD
Dry AMD usually progresses slowly. The majority of people with the condition retain good vision, although advanced dry AMD can lead to severe loss of central vision due to thinning of the retina.
Wet AMD
The wet form of AMD is characterised by abnormal blood vessels growing underneath the retina. These blood vessels leak and damage the macula (responsible for reading, watching TV, and recognising faces). There are effective treatments for wet AMD which often stabilise or improve vision, but there is no cure.
What causes it?
What are the main risk factors for developing AMD?
There are a number of risk factors for developing AMD, the main ones are listed below:
1. Age - this is the biggest risk factor and the chance of developing AMD increases with advancing age over 50 years
2. Family history - people with a family history of AMD are at a higher risk of developing the condition.
3. Cigarette smoking – this increases the risk of developing AMD by approximately three times
Symptoms
What are the symptoms of AMD?
In the early stages, AMD may not affect your vision. However, as the condition progresses, you may notice one or more of the following symptoms:
1. Blurring of central vision – this may lead to difficulties with reading, watching TV or recognising faces
2. Distortion of vision - straight objects (e.g. a door frame) may appear wavy. This is more noticeable when you close your other eye.
Diagnosis
How is AMD diagnosed?
AMD may be diagnosed after a comprehensive eye examination is performed by your retinal specialist. This will include a vision test and dilated eye examination. Further tests to confirm the diagnosis and assess its severity are often needed. These tests include Optical Coherence Tomography (OCT) and Fluoroscein Angiography.
Treatment
What are the treatment options for wet AMD?
1. Eating a healthy diet rich in green leafy vegetables and oily fish.
2. Stopping smoking
3. Vitamin Supplements – research has shown that taking anti-oxidant vitamins may reduce the risk of loss of vision in people AMD of intermediate severity but they willl not recover vision that has been lost.
For wet AMD, additional treatments are available:
Anti-VEGF injections - these new medicines are highly effective treatments for wet AMD in selected patients. They are delivered by injection into the eye and have been used to successfully treat many thousands of people around the world. Anti-VEGF injections work by blocking the action of a substance called vascular endothelial growth factor (VEGF) which is important in the growth of the abnormal blood vessels that occurr in wet AMD. Anti-VEGF injections are effective in stabilising or improving vision in a high proportion of patients.
Photodynamic Therapy (PDT) - PDT was developed to decrease the amount of ‘collateral damage’ to the retina. A light sensitive dye (which is injected into the blood stream) concentrates the effect of a laser onto blood vessels leaking under the macula, thus minimising damage to the retina.
Disadvantages of PDT include the high rate of re-growth of the abnormal blood vessels if used as a single treatment, thus it is usually used in combination with the intr-vitreal steroids or anti-VEGF injections. The AMD disease process means that the nautural history of AMD patients is that the blood vessels tend to re-grow (and this holds true for all treatments) and patients often retreatment.
Intravitreal injection of steroids - steroids can be delivered into the eye for maximum effect on the retina. Steroids may stop abnormal blood vessel growth when used in combination with other treatments such as photodynamic therapy.
Combination treatments - in some cases, a combination of the treatments above may be recommended.
