Age-Related Macular Degeneration

At the back of the eye, there is a light-sensitive membrane called the retina. Its function is similar to the film in a camera. The eye focusses light onto the retina in order for us to see clearly. At the centre of the retina is a highly specialized region called the macula. The light sensitive cells are packed closely at the macula, and we need a healthy macula to see clearly.

Age-related macular degeneration (AMD) is a common condition in our population. About 1 in 7 people have at least some AMD. The risk of AMD increases with age and is associated with a family history and smoking.

There are 2 main types of AMD: the dry type and the wet type. In the dry type, the macula becomes “moth-eaten” and gradually stops working properly. This causes a gradual loss of central vision. In the wet type, abnormal blood vessels grow into the macula and bleed.

AMD is diagnosed by an examination of the back of the eye. This often involves dilating the pupil with a drop and a scan of the macula with an instrument called OCT is usually performed. 

This modern imaging technique, which is a bit like ultrasound but with laser light, provides detailed information about the macula. It is completely painless and quick.

The dry type has no definite treatment; however, supplements such as Macuvision may reduce progression. Dark leafy greens, yellow fruits and vegetables, fish, and a balanced, nutrient-rich diet have been shown beneficial for people with AMD.

If the dry type is diagnosed it is important to monitor the vision and watch out for changes such as a sudden deterioration in vision or distortion of vision. This may indicate that the dry type has become wet.

The wet type is treated by ongoing injections of a special drug called an anti-VEGF into the eye which dries up the abnormal blood vessels. This treatment can reduce progression and recover some vision. 

The injections are usually performed in the clinic on a regular basis. This usually involves 3 injections separated by a period of 4 weeks and then gradual extension of the time between injections to a maximum of about 3 months. An OCT is used to monitor treatment effect.

There is a lot of ongoing research into the causes of AMD and new treatments are being studied. There is hope that in the future, injections into the eye will no longer be necessary and that nerve cells in the eye can be repaired.