Causes of macular degeneration

The exact cause of macular degeneration isn't known, but the condition develops as the eye ages.

Age-related macular degeneration (AMD) is caused by a problem with part of the eye called the macula. The macula is the spot at the centre of your retina (the nerve tissue that lines the back of your eye).

The macula is where incoming rays of light are focused. Ithelps you see things directly in front of you and is used for close, detailed activities,such asreading and writing.


As you get older, the light-sensitive cells in themacula can start to break down. This tends to occurgradually, often over many years.

Waste products can also begin to build up in your retina, forming small deposits called drusen. Drusen are a common feature of dry AMD and tend toincrease in size as the condition progresses.

As dry AMD progresses, you'll havefewer light-sensitive cells in your macula, causing your central vision to deteriorate. A blurred spot will developin the centre of your vision, making your central vision less well-defined. As a result, you may need more light when reading and carrying out other close work.


In cases of wet AMD, tiny new blood vessels begin to grow underneath the macula. It's thought these blood vessels formas an attempt by the body to clear away the drusen from the retina.

Unfortunately, the blood vessels form in the wrong place and cause more harm than good. They can leak blood and fluid into the eye, which can cause scarring and damage to your macula.

The damage and scarring causes the more serious symptoms of wet AMD to develop, such as distorted vision and blind spots.

Increased risk

It's unclear what triggers the processes that lead to AMD, but a number of things increase your risk of developing it. These are described below.


The older a person gets, the more likely they are to develop at least some degree of AMD.

Most cases start developing in people aged 50 or over and rise sharply with age. It'sestimated1 in every 10 people over 65 has some signs of AMD.

Family history

AMD has been known to run in families. If your parents, brothers or sistersdevelop AMD, it's thought your risk of also developing the conditionis increased.

This suggests certain genes you inherit from your parents may increase your risk of getting AMD. However, it's not clear which genes are involved and how they're passed through families.


A person who smokes is up to fourtimes more likely to develop AMD than someone who's never smoked.

The longer you've been smoking, the greater yourrisk of getting AMD. You're at even greater risk if yousmoke and have a family history of AMD.

This could be the result of genetics.

Other possible risk factors

The following things may increase your risk of developing AMD, although this hasn'tyet been proven.


It's possible drinking more than four units of alcohol a day over many years may increase your risk of developing early AMD.


If you're exposed to lots of sunlight during your lifetime, your risk of developing macular degeneration may be increased. To protect yourself, you should wear UV-absorbing sunglassesif you spend long periods of time outside in bright sunlight.


Some studies have reported being Obesity having a body mass index (BMI) of 30 or greater may increase your chance of developing AMD.

High blood pressure and heart disease

There's some limited evidence that having a history of high blood pressure (hypertension) or coronary heart disease may increase your risk of developing AMD.

The macula is a small spot at the centre of the retina. It is the part of your eye where incoming rays of light are focused.
The retina is the nerve tissue lining the back of the eye. It senses light and colour and sends it to the brain as electrical impulses.
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Medically Reviewed by a doctor on 28 Nov 2016