Age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness. It is just one form of macular disease, which affects the eye's retina.

An estimated 500,000 people in the UK suffer from AMD, 40% of these are over the age of 75.

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What is AMD?

AMD is the most common form of macular disease, which affects the central part of the retina.

It is an age-related process and usually develops after a person reaches 50 years.

It generally involves both eyes, although they may not be affected at the same time or to the same degree.

Some 90% of these cases are dry AMD which cannot be treated but 10% are wet ADM.

Dry AMD means visual cells simply stop functioning.

Wet AMD is by far the most aggressive form of the disease.

The condition is caused by the growth of new blood vessels under the centre of the retina.

These can leak fluid, causing scar tissue to form and destroying central vision in a period of between two months and three years.

Peripheral vision is retained. The condition causes problems reading, seeing small objects and distorted vision.

What are the symptoms?

In the early stages of AMD, central vision may be blurred or distorted. Objects may take an unusual size or shape.

This process can happen quickly or develop over several months.

People with the condition may become very sensitive to light or actually see lights that are not there.

There may be some discomfort, although overall the condition is not painful.

How is AMD treated?

There is no treatment for dry AMD, but there are a number of treatments for the wet form of the condition.

Photodynamic therapy involves the injection of a light-sensitive medicine called verteporfin into a vein in the arm.

The medicine is able to identify the abnormal blood vessels in the macula, and attach itself to proteins in those vessels.

The medicine is then activated - by a laser which is shone into the eye - to destroy the rogue vessels.

This stops the vessels from leaking blood or fluid, therefore stopping the damage the vessels are causing to the macula.

The technique is designed to ensure that none of the healthy, but delicate tissues in the eye are damaged.

However, it can only be used on a proportion of patients.

A newer type of drug treatment for wet AMD is known as anti-VGEF (vascular endothelial growth factor) medication.

It works by blocking one of the key chemicals responsible for the growth of the new blood vessels.

The anti-VGEF medication has to be injected into your eye using a very fine needle.

The National Institute for Health and Clinical Excellence (NICE) approved Lucentis, an anti-VGEF medciation, for use in England and Wales in 2008.