Age Related Macular Degeneration AMRD/AMD
WHAT IS ARMD?
Age related macular degeneration or ARMD is the degeneration of one macula in the central part of the retina. (The light sensitive screen at the back of one eye) that allows one to see fine details. ARMD is the common cause of vision loss in those over 50 and its prevalence increases with age. ARMD affects mainly the macula which is the part of the retina that allows the eye to see fine details and also the centre of the field of vision. Degeneration results from a partial breakdown of the retinal pigment epithelium (RPE) which is the inner layer between the retina and the choroid (the layer of blood vessels behind the retina). The RPE acts as a selective filter to determine what nutrients reach the retina from the choroid. Many components of blood are harmful to the retina and are kept away from the normal RPE. Breakdown of the RPE interferes with the metabolism of the retina, causing thinning of the retina(the “dry” phase of macular degeneration). These harmful elements may also promote new blood vessels formation and fluid leakage (the “wet” phase of macular degeneration). This disorder results in the loss of central vision only; peripheral fields are always maintained. The risk factors for ARMD are hypertension, smoking and family history of ARMD.
WHAT CAUSES ARMD?
In dry ARMD, the cells that make up your macula break down over a period of time, as you age causing the thinning of your macula.
There is abnormal growth of new blood vessels beneath your retina which may leak fluid or blood in wet ARMD.
RISK FACTORS FOR DEVELOPING ARMD ARE
- Increasing age
- Family History of ARMD
- High cholesterol or blood pressure
WHAT ARE THE SYMPTOMS OF ARMD?
- Gradual painless decrease in your central vision or even a blind spot
- Requirement of increasingly brighter light for doing close work with haziness of printed words
- Reduced brightness of colors
- Difficulty in adapting to low light levels like a dimly lit room
- Visual distortion like straight lines appearing wav
- Hallucinations of animals, people or shapes in advanced stages
HOW TO DETECT ARMD?
- As initially it is a silent disease, mostly it is picked up during routine examination by an Ophthalmologist
- The retinal examination done by an Ophthalmoscope will show the findings of this disease process
- To assess the condition in detail, certain other tests are done:
- Amsler Grid: Very simple test done at home to pick up early stages of ARMD
- Fluorescein Angiography / ICG: Photographs of macula are taken after injecting a dye in patient’s arm. The dye reaching the eye helps to clarify the type and extent of disease, including detail of abnormal vessels, leaks and membrane formations
WHAT IS THE TREATMENT FOR ARMD?
- For DRY ARMD, apart from the use of anti-oxidant medicines, no other treatment is available
- Medications which are injected directly into your eye
- Laser photocoagulation to destroy abnormal, leaky blood vessels
- Photodynamic Therapy in which a laser activates a drug which is injected in your arm. The drug collects in the abnormal blood vessels and damages them
- Surgery for implantation of a telescopic lens is one eye