What is Age-Related Macular Degeneration?
Age-related macular degeneration (AMD) is a common eye condition affecting older people. Individuals suffering from age-related macular degeneration experience partial or total loss of their central vision in one or both eyes. There is no pain associated with AMD. About 4.7% of the Indian population suffers from age-related macular degeneration.
The macula is a small part of our retina that has highly sensitive cells responsible for clear, sharp, central vision. A healthy macula enables a person to see details of an object. A healthy central vision helps us in driving, sewing or reading small prints without much effort.
With age, the macula starts losing its abilities of a sharp, clear central vision and this condition is known as age-related macular degeneration. For a layman, it is a condition causing weakening of the vision. Those affected start feeling difficulties in seeing the fine details of the image in front of their eyes. The side vision is not affected at all.
AMD is classified into two types: Dry AMD and Wet AMD.
Very rarely, a third type of condition called Juvenile Macular degeneration is seen in young people suffering from some genetic disorders such as Stargardt’s disease, Best’s Disease or Sorsby’s dystrophy.
- Dry AMD: Around 85% of the AMD cases are account for dry age-related macular degeneration. Dry AMD progresses slowly. Thinning of the macula tissue results in loss of central vision. A kind of fatty protein, either yellow or white known as Drusen starts accumulating in and around the macula.
- Wet AMD: 10-15% of the AMD patients suffer from Wet AMD. It is more damaging and progresses rapidly. Dry AMD sometimes starts progressing into wet AMD. To correct the damage, new blood vessels grow beneath the retina. These blood vessel starts leaking blood and other fluid that severely damage the retinal cells, affecting the macula and central vision.
If wet AMD is not treated on time, it may result in total loss of central vision. There is also a risk of both the eyes being affected by wet AMD.Wet macular degeneration is further divided in two types.
Wet macular degeneration is further divided into two types.
- Occult- Less pronounced new blood vessels grow beneath the retina. Less leakage from these blood vessels causes less damage to the macula.
- Classic- Pronounced new blood vessels resulting in more leakage, doing severe damage to the macula.
There are three stages of AMD:
- Early AMD: The onset of AMD is symptomless with no vision problems. A regular eye checkup helps in detecting drusen’s presence in the retina.
- Intermediate AMD: Most of the patients do not experience central vision loss. At this stage of AMD, noticeable drusen would be present in the retina. Sometimes there is a change in the retinal pigmentation as well.
- Late AMD: Loss of central vision and drusen formation is very much pronounced in this stage. There is considerable damage to the macula. Dry and wet AMD is determined after proper investigations.
Causes and risk factors
Although the exact cause of the age-related macular degeneration is still being researched. There are many factors that can pose a risk of getting AMD.
Some of the risk factors that contribute to AMD are:
- Age: Ageing is a major cause of age-related macular degeneration.
- Genetic inheritance: Few genes are found to increase the risk of a person getting AMD.
- Smoking: Smokers are at a higher risk of suffering from AMD.
- Exposure to sunlight: Exposure to the UV rays might increase your chances of getting AMD.
Symptoms and signs
Early symptoms of age-related macular degeneration could be easily missed out. AMD is painless; therefore the symptoms are only related to the vision.
Other symptoms are
- Weak eye sight, patients find it difficult to read small print, need bright light to see
- Blurry vision
- Not able to see fine details of anything or recognise a face
- Colours seem dull
- Straight line appears wavy or distorted
- Black spot in vision
- Perception of different size of the same object from each eye
For wet AMD, these symptoms appear very fast and deteriorate within a short span of time.
Amd is perceived as a weakening of eyesight with age. Therefore, not much attention is paid to the early onset of the disease.
A proper eye checkup is needed to diagnose AMD. Following eye tests can be done to diagnose AMD.
Visual Acuity Test: a simple test done at any eye clinic or optician to check your eyesight.
Dilated eye exam: eye drops are given to dilate the pupil of the eye. The doctor can get a better view of the retina and does detail investigation to rule out AMD.
Amsler Grid: An AMD patient will find the straight lines either wavy or distorted.
Fluorescein angiogram: Pictures of the blood vessels of the eyes are taken by injecting a yellow dye. This helps in identifying the leakage and the damage suffered by the retina.
Optical coherence tomography: an advanced scanning of the macula is done to determine the abnormal blood vessels.
Treatment and prevention
There is no treatment to restore loss of vision in AMD.
The anti-vascular endothelial growth factor can be injected to block the growth of new blood vessels.
The doctor depending on each case may advise photodynamic therapy. This therapy helps to slow down the degeneration of the macula to a certain degree.
Laser surgery is another option, in which laser rays destroys the abnormal blood vessels.
Research in radiotherapy, macular translocation, lens implantation, and stem cell therapy is being done to treat AMD.
Lifestyle changes and making healthy choices are recommended to cut down the risk of AMD. Quit smoking and eat foods that are rich in minerals and vitamins. Wear sunglasses. Exercise and weight management are important too.
Regular eye checkup should be done.
Patients of AMD may start facing difficulties in doing routine work like reading, driving, watching TV etc. Some patients get depressed. In rare cases, a patient starts hallucinating.
Consult your doctor if you are having vision loss. Don’t ignore any symptoms of weak vision.
Consult your doctor immediately if you find your vision deteriorating very quickly.
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