Age-related macular degeneration
The macula is the central part of the retina that is involved in central sharp vision. Age-related macular degeneration (AMD) is one of the leading causes of irreversible visual loss in individuals over the age of 60.
AMD can be broadly classified as:
1 / Non-exudative or Dry AMD
This is the more common form, accounting for 90% of AMD cases. There is a slow progressive deterioration of the nerve function.
2 / Exudative or Wet AMD
This makes up 10% of cases of AMD and may cause devastating visual loss. In some instances, good vision may be lost within a few days. It results from the development of abnormal leaky vessels or a membrane beneath the retinal layer. These abnormal vessels may bleed or leak fluid, proteins or fats. This can give rise to a separation of the retinal layers and loss of vision. In the late stage, this may lead to scarring over the macula.
In dry AMD, there can be a gradual progressive loss of central vision. People may not realise they have this until the disease is more advanced and the central vision becomes blurry or distorted.
In wet AMD, there may be a sudden dramatic loss of vision. There may also be distortion of vision or a shadow over the central vision. The visual loss may be profound.