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Minerva Oftalmologica 2019 September-December;61(3-4):58-65

DOI: 10.23736/S0026-4903.19.01833-6

Copyright © 2019 EDIZIONI MINERVA MEDICA

language: Italian

Diet in reducing phototoxic retinal damage

Maria ALTOMARE COCCO 1 , Patrizia ROBERTO 1, Igino CIRULLI 2

1 Department of Ophthalmology, Hospital of Foggia, Foggia, Italy; 2 Department of Surgery, Hospital of Foggia, Foggia, Italy



Photochemical damage is believed to be the most common mechanism by which exposure to light causes damage to the retina. Already in 1966 Noel proposed this hypothesis. The photochemical retinal damage is probably associated with exposure to free radicals. The retina on the other hand has various systems that allow it to protect itself from this insult, and therefore it is logical to think that the damage can occur above a threshold value correlated to the physiological protection systems, biochemical and physical. The visual capacity is linked to the transduction of the luminous stimulus through a complex interaction between the different structural and functional components of the eye and the brain. Visual perception is initiated when light reaches the retina, but light has a toxic potential capable of inducing injury to the same eyes both in the anterior segment (pterygium) and the retina (AMD), a well-known and documented feature both in the clinical literature and in the basic one. The ability of light to induce damage on the neurosensory retina and on the underlying structures has been known for many years. However, the eye has adapted with different defense mechanisms to protect itself from such events, despite this the chronic or acute exposure to light can cause temporary or permanent damage. Luminous or electromagnetic radiation can cause, as it is known, age-related macular degeneration which is the leading cause of legal blindness in Western countries. It is defined as a multifactorial pathology, among the various causes light covers a not secondary role in the etiology of the AMD. The purpose of this study is to highlight the biochemical mechanisms that at present are considered the basis of phototoxic damage and the protective action of some food antioxidants. Nature often amazes us by proposing situations that are certainly paradoxical, a case being the one called the “oxygen paradox”. 21% of the air we breathe is composed of oxygen, we breathe it in the awareness that its presence is essential for our survival. But oxygen at the same time can form various unstable free radical molecules of high reactive mind oxygen known by the acronym of ROS, very damaging to cells. No less paradoxical is the eye/light relationship, in fact, the visual capacity is linked to the transduction of the luminous stimulus through a complex interaction between the different structural and functional components of the eye and the brain. Foods rich in lutein and zeaxanthin can be considered the most targeted to combat blue light damage. These two pigments, indeed, are physiologically present in the central portion of the retina and together with the mesozeaxanthin constitute the macular pigment. These substances are carotenoids that have an absorption peak in the blue light band, providing a natural protection against this high-energy light band. It has been shown that by supplementing orally with Lutein and Zeaxanthin both as a supplement and as a food, it is possible to increase the optical density of the macular pigment by increasing the protective factor due to it.


KEY WORDS: Blindness; Lutein; Zeaxanthins; Antioxidants; Photoreceptor cells; Ozone

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