Age related Macular Degeneration


Retinal Disorders: Age-related Macular Degeneration

AMD (Age-related Macular Degeneration) is a degenerative progressive chronic pathology with a tendency to become bilateral, affecting the macula, the central area of the retina responsible for distinct vision of image details.

There are two forms of AMD:

- the "dry" form, which covers about 90% of all macular degeneration characterised by the accumulation beneath the macula of yellowish material deposits, the drusen, which gradually alter the functionality of the photoreceptors, the cells responsible for light stimuli perception;

- the "wet" form, fortunately less frequent than dry AMD, but with more debilitating outcomes , characterised by the formation of abnormal blood vessels beneath the macula. These vessels, with very fragile walls, can easily allow liquid to exude, or they may break, causing  haemorrhages in the retina.

Although the causes of the disease are not yet fully known, some risk factors have certainly been identified. First of all age (the risk of onset of this pathology increases with age), in addition to other risk factors: demographics (age, sex, ethnic factor), environmental and genetic (family history, smoking, alcohol consumption, diet rich in saturated fats and low in fish, fruits and vegetables, obesity, lack of physical activity, prolonged exposure to sunlight.

Symptoms

AMD initially manifests as a gradual reduction in visual acuity associated with altered and distorted perception of the images (lines appear wavy). More light may be needed to read and difficulty to recognise people, unless they are very close. Sometimes it occurs with opaque spots (scotomas) in the centre of the visual field, but often the symptoms are masked by the fact that the problem affects only one eye.
In the "dry" form the loss of central vision occurs slowly and gradually, and it is possible to see a black spot in the centre of the visual field. Whereas in the "wet" form, the loss of central vision is unfortunately very fast.
If any of the symptoms described appear, it is better to undergo an eye examination as soon as possible.

Diagnosis

The ophthalmologist may diagnose AMD during the eye examination that includes among others: visual acuity test, ocular fundus examination in dilated pupil, examination of the optic papilla and the Amsler test. The latter is a grid similar to an exercise worksheet with a black dot in the centre that the ophthalmologist will ask you to look at, one eye at a time, staring at the central dot. The vision of wavy lines, spots, or the absence of some lines on the grid must be reported to the doctor.

If the ophthalmologist suspects AMD, additional tests may be required such as fluorescein angiography or indocyanine-green angiography angiography, which are useful to detect alterations in retinal circulation or choroid.
There are two more important non-invasive diagnostic tests:

- optical coherence tomography (OCT), which allows you to observe, without any contrast media, retinal sections in high definition;
-  Microperimetry, which allows the evaluation of the visual sensitivity of each point of the macula.

Treatment

For dry AMD (non-exudative) it is widely recognized the importance of using specially formulated dietary supplements to slow the progression of the disease, by the guidelines of the American Academy of Ophthalmology (A.A.O.), official agency of reference for the Ophthalmologists around the world.

Dietary supplements designed to slow  AMD progression include:
- vitamin C and vitamin E, which act by slowing ageing processes and cellular degeneration caused by the production of free radicals.
- zinc, involved in many enzymatic activities, localised at retinal level.
- copper, an essential oligoelement for the activity of numerous enzymes, which always complements zinc intake.
- lutein and zeaxanthin, carotenoids that accumulate in the central part of the retina (the macula lutea), forming the macular pigment, an important eye protective shield.
- astaxanthin, the most powerful antioxidant present in nature provided also with anti-inflammatory and antiangiogenic properties.
- ω -3 fatty acids, called "essential" because they cannot be synthesised by the body, but must be taken as part of your diet. Major constituents of the outer membrane of photoreceptors, have anti-inflammatory and antiangiogenic activities.

Several preclinical and clinical studies have demonstrated the protective effects of all of these components against the risk of AMD progression.
 
For the treatment of wet AMD (exudative) today there are numerous therapeutic options, from traditional ones, such as laser photocoagulation and Photodynamic therapy (PDT) to the latest antiangiogenic drug therapy. Laser photocoagulation consists of using a laser beam of particular strength to destroy abnormal blood vessels developed  in the retina. In some cases it is possible to use Photodynamic therapy (PDT), which selectively destroys abnormal blood vessels through the intravenous injection of a photosensitive pharmacological substance which is activated by laser treatment.

Revolutionary and major therapeutic innovations is the use of intravitreal injections of some antiangiogenic substances, which are able to stop the formation of new vessels (pegaptanib,ranibizumab, bevacizumab, aflibercept).
 
 SIFI proposes a range of nutritional supplements formulated specifically to ensure adequate dietary intake to maintain the health of the retina.

 
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