Age-related macular degeneration (AMD) is a condition which affects people as they get into their 50s or older. There are early forms of AMD which may not cause vision loss or other symptoms but may be noted at a routine visit to a High Street Optician. There are more advanced forms which can cause vision loss and need further investigation to help find out if treatment is needed or possible.
Dry AMD is the name given to the type of AMD in which waste material builds up underneath the retina and can lead to problems in the function of light sensitive cells. In advanced cases of dry AMD (sometimes called atrophic AMD or geographic atrophy), there is thinning of the retina with loss of the health light detecting cells (photoreceptors) and other cells necessary for clear vision (the retinal pigment epithelium). Recent research has shown that the blood rich layer which nourishes the light-sensitive cells of the retina may also be thinned in advanced dry AMD. New treatments are currently being tested in research trials in the UK and other countries.
Wet AMD (also called exudative or neovascular AMD) is associated with growth of fragile blood vessels into and below the retina (choroidal neovascularisation). These blood vessels leak and bleed leading to rapid loss of vision or symptoms of distortion in patients. It is important to understand that AMD can be a progressive condition and the underlying process is one of dry AMD which can worsen from early to late or advanced forms of the disease leading to loss of light detecting cells . At any stage along the path of progression from early to late dry AMD, bloodvessel leak (wet AMD) can occur leading to more rapid loss of vision or other symptoms such as distortion.
The biggest risk factor for AMD is age. Smoking is also a risk factor for the development of AMD. There are also many different types of genes which are associated with an increased risk of AMD.