Age related macular degeneration
What is age related macular degeneration?
The central part of the retina as it undergoes aging changes it leads to the deposition of a waste material that collects under the retina. These are yellow coloured deposits (drusen) and are the early signs of age-related macular degeneration.
What causes age related macular degeneration?
The exact cause is not fully understood, but scientists believe genetics, ageing, smoking, exposure to sunlight and diet may have a role to play.
The importance of diet in maintaining the health of retina:
Certain nutrients in diet protects the body from damaging substances, called oxidants. These oxidants are thought to be partly responsible for the ageing process in the eye.
Antioxidants reduce this harmful effect.
What are antioxidants, and how are they helpful?
Vitamin A, C and E are antioxidants. Carotenoids are also effective against oxidants. Lutein and zeaxanthin are important carotenoids. The human body cannot make lutein or zeaxanthin, and they must be obtained from food. Several studies suggest that eating at least 10mg of lutein a day has the most beneficial effect on the retina. While it is important to eat a wide range of foods, the following vegetables have the highest amount of lutein. These are: Kale, red pepper, spinach, lettuce, leek, broccoli and peas. Eggs also contain lutein and zeaxanthin. Two large studies called the age-related eye disease study (AREDS1 and AREDS2) suggested that certain nutritional supplements can slow the progression of age-related macular degeneration by about 25%.
Who are more likely to need nutritional supplements?
1. If you have a diet low in fresh, green, leafy vegetables and fruit
2. Your eye examination reveals medium sized drusen, or one or more large drusen in one or both eyes
3. You have wet macular degeneration in one eye, but good vision, and dry macular degeneration in the other
What is the role of smoking?
People who smoke are 4x more likely to develop age related macular degeneration than those who do not, regardless of their genetic risk. If you smoke, you should not take any supplement with beta-carotene, as evidence suggests it increases the risk of lung cancer.
What are the types of macular degeneration?
There are two types:
1. Dry age-related macular degeneration
2. Wet age-related macular degeneration
The majority >90% have dry age-related macular degeneration. Whereas, 10% have wet macular degeneration.
What happens in dry macular degeneration?
This type leads to a gradual loss of vision over a period of years. The ability to read the small print is the first symptom of this type of macular degeneration. One may notice some distortion while reading, which usually progress very slowly. Eventually, this may lead to severe sight impairment. There is no treatment for this condition.
What happens in wet macular degeneration?
In the wet type, abnormal blood vessels grow behind the retina, causing leakage of fluid, blood or fat. This causes the retina to swell and not function properly. Usually wet macular degeneration starts suddenly, with altered and decreased near vision. This may also cause difficulty in reading, recognising people’s faces, along with a distorted view of the outside world. Most of the cases will lead to severe visual impairment, unless treated urgently.
What is the treatment for wet macular degeneration?
wet macular degeneration can be treated by injecting a drug into the eye.This works by shrinking the abnormal, leaking bloodvessels. There are three drugs which are used. These belong to a class of compounds called anti-VEGF agent. They are:
1. Ranibizumab (Lucentis)
2. Aflibercept (Eyelea)
3. Bevacizumab (Avastin)
The treatment aims at preserving the sight. 30-45% patients can expect significant improvement in their visual acuity. This treatment does not lead to complete cure of the condition. The treatmentinvolves constant surveillance over a long period of time.
Useful website : www.macularsociety.org/resources