Macular Degeneration
What is Age-Related Macular Degeneration (ARMD, AMD)?
Age-related macular degeneration or AMD is caused by microscopic changes in the central part of the retina. AMD causes gradual changes in the macula which is the area of the retina with the highest concentration of photoreceptors. These changes typically start after the age of 50, and are categorized into two main types.
Dry AMD
Dry macular degeneration refers to changes in the thin pigment layer under the macula. In dry AMD there is no accumulation of fluid or edema. In the majority of cases this condition is asymptomatic, and mild changes in the vision that may occur are usually attributed by the patient to possible changes in their spectacles prescription. In an exception, dry AMD may cause a significant loss of vision in a variant type called geographic atrophy.
Wet AMD
Wet macular degeneration is caused by a membrane which develops under the retina and causes leakage and accumulation of fluid and/or blood. Wet AMD may cause a significant loss of vision and distorted central vision (metamorphopsia). Prevention of irreversible damage to the retina with wet AMD demands prompt medical care.
Is there an association between dry and wet AMD?
In the majority of cases, dry AMD precedes the formation of wet AMD. Therefore, every person with dry age-related macular degeneration must be under surveillance for the development of the wet form of AMD. This includes self-monitoring of the vision, periodic retinal imaging of the macula with OCT, and apt retinal evaluations.
What are risk factors for the development of AMD?
Age-related macular degeneration is diagnosed after the age of 50. Family history of AMD, nutrition, smoking and hypertension are risk factors.
How is AMD diagnosed?
AMD is diagnosed by examination of the retina after pupil dilation.
How are wet and dry AMD treated?
The treatment of dry AMD is aimed at influencing modifiable risk factors such as control of hypertension, as well as having good nutrition and physical exercise. There are dietary supplements which reduce the risk of conversion from dry to wet AMD.
The best treatment option for wet AMD starts with early diagnosis. Prompt treatment many times results in improved vision. There are a number of good therapies for wet AMD. The best treatment strategy is planed after carefully obtaining the patients history, examination of the retina and evaluating imaging studies.