Age-related macular degeneration is known to be the leading cause of blindness and low vision in the Western world. In Italy it affects about one million people, 2-300 thousand in advanced form, in which sight begins inexorably to compromise. The incidence increases with age, and for the dry form, which is more widespread, there are currently no pharmacological therapies. However, it is possible to act on the risk factors, and to resort to supplements with high doses of antioxidants, capable of slowing the progression of the disease for a small but still relevant fraction of patients. A therapeutic strategy scientifically confirmed by the new long-term results of the AREDS2 study, just published in the journal Jama Ophthalmology by a research consortium coordinated by the US National Institute of Health (Nih).
“This is a strategy that has been known for decades at the eye level, supported by years of clinical practice”, explains a Salute Matteo Piovella, president of the Italian Ophthalmological Society. “Those used today are two pigments with antioxidant effects, lutein and zeaxanthin – continues Piovella – present in an accentuated way in the macula, which in fact has their own colors: red and yellow. Their effect is to protect the eyes from oxidative stress. , that is from aging and age-related pathologies, such as age-related macular degeneration “.
Although these are substances used for decades, and with an excellent rationale of efficacy, in recent years some perplexity had arisen about the advisability of recommending their supplementation in patients with age-related macular degeneration. Because of – explains Piovella – the scarcity of irrefutable data on their effectiveness. And some perplexity regarding the safety of antioxidants: in the formulation initially tested by the Nih in the 90s, instead of lutein and zeaxanthin, there was in fact beta-carotene, a substance generally beneficial for our body, but which according to some research, emerged in the following years, in case of supplementation it could increase the risk of developing lung cancer, especially in the presence of risk factors such as cigarette smoking.
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Since many patients with age-related macular degeneration are also smokers (cigarettes are also an important risk factor in this case), the use of beta-carotene was therefore considered dangerous. And in a second study, AREDS2 started in 2006, it was replaced with lutein and zeaxanthin. At the end of the trial, the two substances had been shown to reduce the risk of disease progression to an advanced form by about 26%, without increasing the chances of developing tumors. But as this was a single study, and with a follow-up of just 5 years, some perplexities remained in the scientific community.
The new research
In the new research, 3,883 of the 4,203 enrolled in the original study were followed up for a further 5 years, thus covering a period of 10 years from the start of treatment. The results confirmed the effectiveness of the two antioxidants, with a further 20% reduction in the risk of progression of macular degeneration in patients who took lutein and zeaxanthin for the entire decade. The new data also confirmed their safety, while for beta-carotene (originally administered to a group of patients) instead indicate the presence of a doubled risk of lung cancer in smokers and former smokers.
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“These new results will certainly help to overcome the resistance born in the last 10 years regarding the use of antioxidants in the management of age-related macular degeneration”, concludes Piovella. “We have always considered it an important strategy. Deterioration of the macula, the noblest part of the retina, causes severe disability for patients, who lose 90% of their vision. And antioxidants are the only one. therapeutic option available for those suffering from the dry form of the disorder, ie about 70% of patients “.