Macular degeneration

Age Related Macular Degeneration (AMD)

As a retinal specialist, I see patients with AMD nearly every day of my working life. In recent years, there have been major advances in the treatment of AMD which have greatly increased the number of patients that can be effectively treated. I have been treating many of my patients with AMD for many years so we develop relationships over time and I like to get to know them as individuals. Seeing patients improve their sight or avoid losing it and hearing how it impacts their life is the most rewarding part of my work.

What is Age Related Macular Degeneration (AMD)?

Age related macular degeneration (often called AMD for short) is a common condition that affects many people as they get older. 1 in 7 people over the age of 50 years and 1 in 3 over the age of 75 will have signs of AMD. It is caused by a combination of genetic (inherited) and environmental factors such as diet and smoking.

The macula is the central part of the retina where light is focussed onto. It is responsible for clear central vision.

AMD causes progressive damage to the macula, which can ultimately lead to loss of  central vision. This affects many aspects of daily life such as reading, watching TV, driving and recognising faces. It is still the commonest cause of legal blindness in Australia.

Types of AMD

AMD can be classified into dry AMD or wet AMD

 1. Dry AMD can be stable or result in a slow deterioration of central vision. Research has shown that certain anti-oxidant vitamins can reduce the risk of losing vision. The use of anti-oxidants is a long term prevention effect, but does not lead to improved vision.

2. Wet AMD involves blood vessels growing underneath the retina. These blood vessels leak and damage the macula. The vision may become distorted at first, then eventually the central vision may become ‘blacked’ out. As the blood vessel grows sideways, a larger area of the central vision may be lost leading to a large blind spot affecting the centre of vision.

Despite the poor prognosis for central vision, macular degeneration does not take away the peripheral vision.

Treatment options for wet AMD

1. Injection of anti-VEGF agents e.g. bevacizumab (Avastin), ranibizumab (Lucentis) or aflibercept (Eylea).

Anti-VEGF agents are medications designed to block the effects of a substance called vascular endothelial growth factor (called VEGF  for short) which causes abnormal blood vessels to grow and leak fluid in the macula. By blocking VEGF in the eye, these agents can reverse the wet macular degeneration process, often leading to improvement or stabilisation of vision.

The most commonly used anti-VEGF agents are bevacizumab (trade name Avastin) and ranibizumab (trade name Lucentis). More recently a newer anti-VEGF agent has been developed called aflibercept (trade name Eylea).

The safety of anti-VEGF agents such as Avastin and Lucentis when injected into the eye has been confirmed in multiple clinical trials in the treatment of wet AMD and diabetic retinopathy.  Although there is a theoretical risk of side effects such as stroke or heart attack, there is no proven statistically significant evidence that the small dose of Avastin or Lucentis used when injected into the eye can cause similar side effects. Further research into this area is in progress. All eye injections carry a small risk of infection (less than 1 in 1000), bleeding or retinal detachment. These complications can often be effectively treated but can rarely lead to loss of vision.

2. Photodynamic Therapy

Photodynamic therapy (also known as PDT for short) can reduce damage to the retina caused by blood vessels growing underneath the macula. It involves injecting a light activated dye into an arm vein, which then accumulates in the abnormal blood vessels underneath the retina. A laser is then used to activate the dye causing closure of the abnormal blood vessels. Because other treatments (such as intravitreal anti-VEGF injections) are usually more effective, photodynamic therapy is only used for a small number of patients that do not respond to other treatments.

3. Injection of steroids (Triamcinolone or Dexamethasone)

Steroids can be injected into the eye to stop blood vessel growth. Steroids are usually used in combination with other treatments such as photodynamic therapy or anti-VEGF injections. The main risks of steroid injections in the eye include infection, retinal detachment, glaucoma and cataract. These complications can usually be treated, but may rarely lead to loss of vision.

4. Combination Therapies

Depending upon individual circumstances and response to treatment, a combination of the above treatments may be recommended.

More information

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Dr Chen on macular degeneration

Dr Simon Chen explains what macular degeneration is, as well as answering some of the more common questions about the condition and eye injection treatments.

Click on images to view video