But now in the United States a recent investigation may shed some light on this maculae deterioration and help develop new treatments for this eye disorder.

The study, published in Nature Genetics , identified two genes which according to scientists are related to the majority of macular degenerations associated with age.

'We have made huge advances in the treatment of this disease' indicated Dr. Jordi Mones, ophthalmologist from the Ocular Microsurgery Institute of Barcelona. 'In the last months the treatments have changed and this has given us much hope because now we have more certainty in the disease's prognosis' stated the expert.

Genetics

Macular degeneration associated with age is one of the most common causes for the loss of eye sight among people over 50. It is marked with a progressive loss of central vision or visual acuity, due to the deterioration of the maculae, the region in the retina responsible for the 'fine tune' vision.

The study has identified two gene variations related to the disease. 'This is the zone that we use for reading, driving, identifying faces' says Jordi Monés, 'it's the detail vision'.

'The degeneration is produced by the abnormal growth of blood vessels behind the retina which come out of their localization, transforming into scars and eventually a blur or stain in vision.'

In the past, other investigations had demonstrated that diverse variations of a gene factor called Factor H significantly increased the risk of this vision disorder.

Factor H controls the production of a protein which helps to turn off the response of the immune system once an infection was fought successfully. Studies have demonstrated that people with hereditary variations of Factor H are less capable of controlling the swelling caused by infectious factors, which produces the ulterior macular degeneration.

But the previous investigations had found that only one in three people H with this Factor H variation had not been diagnosed with this disease.

Now then, researchers at the Medical Center at the University of Columbia , in New York , discovered that there is another gene which plays a role in this same immune response. After genetic analysis in 1300 people they immediately identified the presence of another gene called Factor B.

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Researchers discovered that while Factor H is an immune response inhibitor, Factor B is an immune activator.

According to scientists, due to the complementary role played by these genes, a protective variation of Factor B could defend against the development of this degeneration. And this they say will occur even if the person carries the risk variation of Factor H.

Investigators have found that 74% of all people with macular degeneration had variations of Factor H or Factor B or both, but they did not carry any of the protective variations of any of these genes.

According to Dr. Jordi Monés, these discoveries are important because they open the possibility to new more specific treatments. 'The end idea is to be able to genetically manipulate this information to correct this defect before it occurs and maybe this can be done in a not distant future' Dr. Monés concludes.

The scientists are now searching for these specific factors that trigger the response of the immune system and subsequent inflammation. But with all the degenerative diseases, a cure has not yet been obtained.

'We have made serious inroads' says Dr. Monés 'and now we cannot only improve the patients' vision but therapeutically intervene at an earlier stage. But with all degenerative diseases the importance is to get there at an early stage were defects may still be corrected'.

'With all this novel genetic research in a not so far away future we will be able to act before the changes that give origin to the disease occur' ended Monés.