Vitamins and eye health

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Monday, 5 November 2018

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Vitamins and eyes

Vitamins contribute to eye healthan assertion that is now confirmed by several scientific studies. Results have, in fact, shown how the Lack or sub-optimal concentrations of certain vitamins may contribute to the onset of certain visual disorders, such as, for example, myopia. Two studies published in recent months illustrate precisely the correlation between eye vitamins and quality of vision...

Study 1: The role of vitamin D in the onset of myopia

Published in Journal of OphthalmologyThis study highlights the close correlation between the blood concentration of vitamin D (25-hydroxyvitamin D, 25(OH)D) and myopia.

Among refractive disorders, myopia is the one that has taken on the characteristics of a major public health problem in recent decades due to an ever-increasing prevalence. Myopia can be corrected with glasses, contact lenses or by undergoing refractive surgery. However, if the refractive error exceeds 6 dioptres, the likelihood of certain complications, such as glaucoma or retinal detachment, increases.

The causes of the onset of myopia are manifold, and scientific studies show that the interaction between genetic (there are more than 200 genes involved in the onset of myopia) and environmental factors underlies the onset of this visual disorder. Indeed, observational studies have shown that Exercising for at least 40 minutes in an outdoor environment can help reduce the risk of myopia occurrence (from 39.5% to 30.4%). According to experts, a possible explanation for the association between time spent outdoors and myopia seems to be related to the production of vitamin D, which is stimulated as a result of the body's exposure to sunlight. Confirming this, several studies have shown that the concentration of vitamin D in the blood of people with myopia is lower than in those without.

Study 2: Vitamin A in the maintenance of the blood-retinal barrier

A study by American researchers at Ohio University (USA) has shown the crucial role of vitamin A in maintaining the blood-retinal barrier (BER). The BER is a physical barrier composed of two layers of cells in close contact that is essential for proper visual function. BER physically separates the blood flow from the retinal nerve tissue. When the BER scaffolding is compromised and its functionality impaired, various complications can arise, including: oedema of the retinal neuronal tissue, retinal vein occlusion, uveitis or other visual pathologies of a chronic nature. For this reason, much research in the field of ophthalmology is directed towards investigating the mechanisms involved in maintaining the correct BER structure. For the first time, the authors of this research have shown that theretinoic acid, a metabolite of vitamin Acan regulate the correct development of BER by promoting the formation of so-called 'tight junctions', which are nothing more than connections between one cell and another, essential in this case for the scaffolding of the BER itself.