Age-related macular degeneration (AMD) is a condition that usually occurs in later life. It causes painless loss of central vision, usually in one eye at a time. It does not cause complete loss of sight or blindness.
The macula is the part of the retina which responsible for central, detailed vision, for example when you look directly at something. The symptoms vary but you may notice difficulty reading small print, or there is a slight smudge or blank patch in the centre of your vision. Straight lines may look distorted or wavy.
There are two main types – dry AMD and wet AMD.
Dry age-related macular degeneration causes a gradual and slow loss of vision. This form of AMD develops when the cells of the macula become damaged by a build-up of deposits called drusen. It’s the most common and least serious type of AMD. Occasionally it can develop into wet AMD.
Wet AMD develops when abnormal blood vessels form underneath the macula, leak, bleed and causing damage to the extremely delicate light sensitive cells, known as photoreceptors.
When this occurs the patient notices relatively sudden onset of blurring or distortion of vision. However it is possible that patients don’t notice the loss of vision for some time as the reduced vision in the affected eye is compensated for by the other healthy eye.
Investigation and treatment need to carried out as matter of urgency;
special photographs are taken of the retina known as OCT (optical coherence tomography) which show the individual layers of the retina and if there are new blood vessels, and fluorescein angiography in which a dye is used to show the new blood vessels leaking.
It is now possible to treat wet AMD with a drug, for example Lucentis or Eyelea, which is injected into the eye. The drugs are anti-VEGFs (vascular endothelial growth factor) which stop the new blood vessels growing. An initial course of 3 injections is given, usually at monthly intervals. We will explain how often the drug will be given and how often monitoring is required. The aim of treatment is to halt the progress of wet AMD and approximately 30% of cases can improve vision.