What is Macular Degeneration
Sometimes the delicate cells of the macula are damaged & stop working &there are many different conditions which can cause this. If it occurs later in life, it is called ?age related macular degeneration ?, also known as AMD it is the most common cause of poor sight in people are age of 60.
The two most common forms of AMD are DRY & WET
Dry? AMD is the most common form. ,it develops very slaoly causing gradual loss of central vision & it is identified by the collection of yellow, fatty deposits called ?drusen? in the macula. Many people find that the vision cells simply working like the colours fading in an old photograph.
Wet AMD
Result in new blood vessels growing behind the retina ,in the macula, causes bleeding & searching, which can lead to sight loss. This develop quickly, causing irreversible blind spots & can lead to blindness. This responds to treatment in the early stages. Both ?wet? and ?dry ?AMD usually involve both eyes, although one may be affected long before the other. ?AMD? is not painful & almost never leads to total blindness as only central vision is affected & pt. will have enough peripheral of side vision to get around &keep his independence.
Possible risk factors includes
- Age
- Genetics
- Smoking
- Sunlight
- Nutrition-diet low in vitamins & minerals & anti oxidants.
How AMD is detected
In early stages central vision may be blurred or distorted ,objects look unusual in size or shape & straight lines appear wavy. This can be tested by Amsler grid charts.
In advance condition
Patient notices a dark spot in the centre of the vision, this makes reading, writing & recording faces very difficult. In some cases, FFA is needed which involves a series of retinal photographs which gives an accurate map of the changes occurring at macula & helps doctors to decide what is best treatment for the patient. In some cases OCT may be needed.
Treatment
There are not much treatment options for dry AMD. Only vitamins A, C, E, B carofene & minerals (Zinc, copper) supplement can help slow down the progress of dry AMD.
The clinically proven treatment for wet AMD
(1) laser photocoagulation : which seals leaky blood vessels.
(2) Photodynamic theory(PDT) : involves infusing a light sensitive drug [VISUDYNE] identifies the new blood vessels, growing in the wrong place behind the retina. A ?cold layer? is then shone into the eye which activates the drug & stops the new blood vessels from growing & prevent too much damage to macula.
Drugs
In recent years a group of drugs called Anti-VEGF(vascular eudothdial growth factor) have been developed which prevent formation of abnormal blood vessels that Occur in 'wet AMD'.
They include Rani bizumab(Lucentis), Pegaptanib(Macugen), bevacizumab(Avastin). These drugs are infected directly into the vitreous of the eye. These may be repeated within 4-6 weeks if needed. So they prevent wet AMD from getting worse & may restore some of the vision.