AMD is a degenerative process that affects the macula (the part of the retina responsible for central vision). Together with cataracts, they are the main reason for loss of vision in people over 60. It currently affects over 20 million people worldwide.

The symptoms may come on suddenly or be perceived progressively over time. This second case is particularly true in cases of dry AMD. Symptoms that can occur are:

  • Straight lines are perceived as wavy (metamorphopsia).
  • Central vision is blurred or hazy, especially in low light environments.
  • Difficult to distinguish colours.
  • A blind spot in the centre (dark or empty area)
  • Greater difficulty reading.
  • Difficult to recognise faces.

There are two types of AMD: dry (atrophic) and wet (exudative).

Dry AMD: This is the most common type (85-90% of cases) and is characterised by an accumulation of protein deposits within the retina, called drusen. Dry AMD may remain stable or progress to wet AMD or to geographic atrophy, involving a loss of photoreceptors which produces a deterioration of vision and for which there is no treatment. Drusen are usually detected in people over 60 (the druse in itself is not a disease). An increase in the size or number of drusen increases the risk of dry or wet AMD. Approximately 10 to 15% of people with dry AMD develop wet AMD; other cases may remain stable or progress to geographic atrophy. Geographic atrophy involves an irreversible loss of photoreceptors without producing an abnormal growth of blood vessels and/or fluid leaks.

Wet AMD: This is the less common version (10-15% of cases) but the most aggressive. Abnormal blood vessels of the back of the retina start to grow below the macula, the region of the retina responsible for the central vision. These new vessels are fragile and leak, causing an accumulation of blood and fluid which raise the surface of the macula above its normal position, causing scarring and the loss of photoreceptors (rods and cones) which allow sight. Damage to the macula occurs rapidly and, if left untreated, wet AMD leads to a rapid and progressive loss of central vision.

It usually affects:

  • people aged over 60.
  • people with relatives affected by AMD.
  • women more than men.
  • Overweight people with a poor diet.

Most cases are dry AMD, with only a minority having the wet form.

As it is linked to ageing, it cannot be prevented. The recommendation is for a healthy diet with adequate levels of cholesterol, maintaining normal blood pressure, an active lifestyle with regular exercise and not to smoke. We also recommend:

  • Eating a healthy diet rich in vitamins C and E, selenium and carotenoids (fresh fruit and dark green vegetables).
  • Taking vitamins specifically formulated for eye health, those high in antioxidants and zinc, as recommended by the AREDS (National Eye Institute’s Age-Related Eye Disease Study). These vitamins are given in the appropriate doses in specific pharmaceutical preparations for AMD.

There is still no truly effective solution for dry AMD today but encouraging progress has been made in recent times. In fact in October 2014, a pilot clinical trial with stem cells (http://www.visionaware.org/blog/visionaware-blog/adult-stem-cells-for-dry-amd-emerging-future-research-from-the-national-eye-institute/12) was carried out with promising results. Numerous clinical studies are also being done to assess the effectiveness of different treatments, some of which are:

  • Lampalizumab (or anti-Factor D)
  • Fluocinolone Acetonide Inserts
  • Brimonidine for AMD
  • Oracea (Doxycycline)
  • Emixustat hydrochloride (ACU-4429)
  • Glatiramer acetate (Copaxone)

Regarding wet AMD, there is currently the possibility of intravitreal antiangiogenic molecule injections (Lucentis and Eylea) to prevent the proliferation of neovessels. Intravitreal injections are achieving very good results, slowing the progression of degeneration and even improving vision on many occasions.

snellen2

Amsler test for a good eye.

snellen1

Test for an eye affected by AMD.

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