What is Age Related Macular Degeneration?
Age related macular degeneration (AMD) is an eye disorder which usually affects older people. It is characterized by loss of central vision resulting from progressive destruction of the macula.
The Macula is the central portion of the retina, the light-sensitive layer of the tissue at the back of your eye that sends visual signals to your brain. The macula is responsible for the sharp, clear central vision. The rest of the retina provides peripheral vision.
Therefore, macular degeneration rarely causes total blindness since it is only the centre of the vision that is affected by it.
What are the types of AMD?
Dry AMD is the most common and the less severe type of the two.
Fortunately the majority of people who suffer from AMD have the dry type. The loss of central vision results from accumulation of certain deposits called Drusen beneath the macula and retina, interfering with their function and causing slowly progressive macular damage. Consequently your central vision slowly gets impaired. In advanced stages, you begin to see blank spots in your central field of vision. Dry AMD usually doesn’t cause very severe vision loss.
Wet AMD is the rarer and the more serious form of AMD. This leads to more severe and rapid loss of central vision. The visual loss results from the development of fragile new blood vessels beneath the retina that leak blood and fluid into the macula causing rapid loss of central vision. Wet AMD may also follow pre-existing dry AMD.
What is the cause of AMD?
The causes of the abnormal processes that lead to dry and the wet types of AMD are not yet known.
What are the risk factors for AMD?
- Old age
- Women are more prone to getting AMD than men
- Having a family member with AMD
- Smoking
What are the symptoms of AMD?
The principle symptom of macular degeneration is impaired central vision, which is milder and slowly progressive in dry AMD and severe and rapidly progressive in wet AMD. Furthermore the vision loss is permanent and irreversible.
- You may not be able to see clearly straight in front of you
- Reading, writing or any work that requires fine vision becomes difficult to carry out
- Straight lines may appear curvy or bent
- Things may appear blurred and indistinct
- There may also be a blank spot in your central field of vision
- Your peripheral vision remains intact, so you can live your life independently
How is it diagnosed?
Your doctor usually diagnoses the condition on the basis of your eye exam and your history. He/she may also do a visual acuity test to check your central vision, using an ophthalmoscopy to examine your retina. Your doctor may also give you an Amsler grid test to detect wet AMD.
What is the treatment?
There is no treatment available for dry AMD at present.
For Wet AMD, treatment options include thermal laser surgery and photodynamic therapy (PDT). However these therapies can’t be used in every patient with wet AMD. Only selected patients can have these treatments.
In thermal laser surgery, lasers are used to burn the retina in an attempt to impound the area of damage. In Photodynamic therapy, new blood vessels are destroyed to limit the harm to the macula. However these treatments cannot restore vision. They only slow down the progression of the disease.
Research is going on to find new successful treatments for both types of AMD.
What is the prognosis?
AMD is a condition that leads to irreversible loss of central vision.
