Age-Related Macular Degeneration (ARMD)

What is the macula, and what is macular degeneration?

The eye works similar to a camera. The front of the eye acts as a lens, focussing the light onto the back of the eye. The structure at the back of the eye is called the retina, with the central part of the retina being the macula. The macula is therefore the most important part of the retina, responsible for central vision. We use the retina for reading, recognising faces and colour vision. 

Macular degeneration is a disease in which the macula is progressively damaged, resulting in a progressive decline in vision. This usually occurs in older people, and therefore the most common form of macular degeneration is called Age-Related Macular Degeneration (ARMD). There are other rarer syndromes which occur in younger people (such as Stargardt's Maculopathy) or run in families (such as Sorsby's Macular Dystrophy).

What are the types of ARMD?

There are 2 types of ARMD: dry macular degeneration and wet macular degeneration.

Dry macular degeneration

Dry macular degeneration (dry ARMD) is the most common form and occurs about 90% of the time. In this type of ARMD, there is a very slow deterioration in vision over many years. The majority of people with dry ARMD will not go blind during their lifetime. Patients with dry ARMD should still monitor their vision regularly, maintain a healthy diet and, if appropriate, take vitamin supplements. 

A small proportion of patients with dry ARMD will convert into 'wet' ARMD, resulting in a rapid deterioration of vision. Patients with dry ARMD should report any sudden change in vision, distortion or new blind spots.

Illustration: below is a picture of a patient with dry ARMD. The yellow patches in the middle of the photo represent drusen, which represent an accumulation of waste products underneath the retina. These are the hallmark of macular degeneration (ARMD).

Illustration: below is an OCT scan demonstrating drusen within the macular region. 

Wet macular degeneration

Wet macular degeneration (wet ARMD) makes up approximately 10% of ARMD. This disease has all of the features of dry ARMD, but in addition has the development of an abnormal blood vessel. This blood vessel usually grows from the choroidal layers of the eye, underneath the macula. This abnormal blood vessel leaks fluid (which is why its called 'wet' macular degeneration), causes severe retinal haemorrhaging and severe retinal scarring. Unfortunately, the natural history of wet ARMD is progressive and profound central vision loss.

Wet macular degeneration causes distortion of vision, new blind spots and a rapid loss of vision if it isn't treated quickly. The best treatment is with regular injections into the eye. This has been shown in large research trials to significantly reduce the risk of blindness. Other forms of treatment include different types of laser, however these are not as effective as the injections. 

Illustration: below is a photo illustrating retinal haemorrhage in a patient with wet macular degeneration.

Illustration: below is an OCT scan of a patient with fluid leaking underneath the retina as a result of an abnormal blood vessel growing from the deep choroidal layers of the eye. This is the hallmark of wet macular degeneration.

What are the risk factors?

Macular degeneration becomes more likely as you become older. It is rare before the age of 50 and affects approximately 14% of people aged between 70 and 79. 

If you have a family history of macular degeneration, your risk is higher than normal. If one of your first degree relatives has ARMD, you risk may be as high as 50%. 

Your age and a positive family history are the major risk factors for ARMD and unfortunately you cannot modify these factors. Other risk factors for macular degeneration include:

Which tests do I need to detect macular degeneration?

Usually a thorough clinical examination is all that is needed to detect macular degeneration. If there is any concern that you may have developed 'wet' macular degeneration, an OCT scan of the macula and fluorescein angiogram may be required.

Autofluorescence photography can be a helpful test to show progression of dry macular degeneration, but is not usually required to make the initial diagnosis. 

Treatment for macular degeneration

Unfortunately there is no cure for either dry or wet macular degeneration. Nutritional supplements have been shown to help slow the progression of disease in some patients. Unfortunately, these have not been conclusively shown to be of benefit in all patients. Dr Johnson recommends AREDS-1 and 2 supplements in selected patients. Currently, there are lots of other supplements that some people recommend, however most of these have not been proven with rigorous scientific randomised controlled trials. Please click here for more information regarding nutritional advice in macular degeneration.

Intravitreal injections into the eye is the most effective way of stabilising wet macular degeneration, but these need to be continued in order to prevent the eye from becoming blind. These injections stop abnormal blood vessels from growing and prevent fluid leakage, haemorrhage and scarring of the retina.  Like all medications, it wears off and therefore, needs to be repeated regularly. This is the only treatment that has been proven to stabilise vision loss in patients with wet macular degeneration.

What can you do to minimise your risk of going blind?

If you smoke, you should seek the help of your GP to stop. Smoking increases your risk of going blind by up to 400%, according to some studies.Some vitamin supplements can help slow the rate of progression of macular degeneration. You can get these over the counter at most pharmacies and health food stores, but you should speak with your GP to ensure that there are no contraindications before you start taking them.You should also eat lots of green leafy vegetables, oily fish and have a serving of nuts once per week.

We also recommend that you monitor your vision regularly, and have your eyes checked each year with your optometrist. Remember: early treatment is very important. Click here for more information regarding monitoring your vision for macular degeneration.

Macular Degeneration seminars

Northern Eye Surgeons occasionally holds educational seminars for patients. If you would like to know more, please click here.

Other resources

Macular degeneration foundation: for general advice and support

Association for the Blind WA: for advice and support

Here is a November 2013 article written by Dr Johnson for the Medical Forum magazine.

 

Dr Joshua Yuen

Dr Joshua is an experienced consultant ophthalmic surgeon, who specialises in retinal diseases and cataract surgery... read more

Dr Brad Johnson

Dr Johnson is an experienced consultant ophthalmic surgeon, who specialises in retinal diseases and cataract surgery... read more