| Age Related Macular Degeneration
in short is one of the leading causes of vision loss in people over 60 years of age. The retina is the light sensitive layer in the back of the eye. The central part of the retina is called the macula .
The integrity of the macula is very vital for sharp central vision. Ageing can cause degenerative changes in the macula, leading to irreversible damage and ultimately central vision loss.
Who are at risk ?
- people over 60 years of age
- women are at a greater risk
- positive family history of ARMD
- excessive exposure to sunlight and ultra-violet rays
- low dietary intake of vitamins and minerals
What are the symptoms of ARMD ?
Distortion in vision causing lines to appear wavy or objects to look out of shape
Decreased central Vision
Colours appear dull and faded
Dark grey spot may appear in the central vision
What are the changes in the eye due to ARMD ?
There are two types of Age Related Macular Degeneration. ‘Dry' and ‘Wet' type.
In ‘dry' ARMD there is a mild and slowly progressive kind of vision loss. The retinal changes are characterized by yellow deposits underneath the retina.
There is no proven treatment available for dry ARMD.
In the ‘wet' type, there is a growth of abnormal blood vessels under the retina which leak fluid and blood into the retina. The central visual loss is severe and thus, early treatment is indicated for preventing further damage to the macula.
How to diagnose ARMD?
* Visual acuity evaluation: A drop in vision could give a clue . It also helps to document any further improvement or deterioration at a later date.
* Test for macula function: Amsler's chart is a paper with a grid pattern on it. Any distortion or appearance of grey areas on the chart is indicative of a macular disorder. This simple test can also be done by the patient at home.
Picture of Amsler chart / wavy lines and grey spot.
* Examination of the fundus / retina:This is done using a slit-lamp bio-microscope with a 90 dioptre or 78 dioptre lens .
* Stereoscopic color photographs of the macula. This is a very useful in documentation of the disease. And further improvement or deterioration can be looked for later.
* Fundus Fluorescein Angiography (FFA) is indicated in wet ARMD when abnormal blood vessels are suspected.A dye is injected into a vein in the arm, and serial photographs are taken as the dye circulates in the eye.
Fundus fluorescein angiography photograph demarcating ARMD
How to treat ARMD ?
Dry type of ARMD has no treatment. The role of antoxidants in preventing further visual loss is commended.
In wet type of ARMD, the aim of treatment is to destroy the abnormal blood vessels growing from underneath the retina. This would help stabilize the vision and prevent further vision loss.
Treatment includes LASER
Transpupillary thermotherapy (TTT) uses a red laser to destroy the abnormal vessels directly. Photodynamic therapy (PDT) is a treatment wherein a dye known as verteporfin is injected through a vein in the arm. This dye collects within the abnormal blood vessel inside the eye. A diode laser indirectly activates the dye verteporfin that has collected within the abnormal blood vessel selectively destroying it.
Treatment includes intra-ocular INJECTIONS
Injections into the eye , certain class of drugs broadly classified as anti-VEGF ( Vascular Endothelial Growth Factors ) antibody often help reduce the risk of vision loss.
ANTI-OXIDANTS are nutrients containing lutein, beta-carotene, VITAMINS C and E, These are useful dietary supplements.
LOW VISUAL AIDS include illuminated hand held devices to help in reading, large print books and papers. Magnified font size in the computer. Telescopic Intra-ocular lenses (IOL) can be inserted in the eye after cataract extraction by phacoemulsification.
What are the factors that can reduce the incidence of ARMD ?
* Eating a balanced diet with plenty of fruits and green leafy vegetables. These are rich source of antioxidants. Antioxidants are basically scavenging molecules which remove metabolic waste products that accumulate in the eye.
* Avoid smoking.
* Wear sunglasses when outdoors in bright sunlight.
* Regular eye examination will enable early detection and treatment of ARMD.