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Phototoxicity is a quantum chemical phenomenon. Phototoxins are molecules with a conjugated system, often an aromatic system. They have a low-lying excited state that can be reached by excitation with visible light photons. This state can undergo intersystem crossing with neighboring molecules in tissue, converting them to toxic free radicals ...
Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity .
Phototoxins are toxins that can cause allergic reactions in particularly susceptible individuals and which can cause dangerous photosensitivity in a much broader range of subjects. Phototoxins are common in: a variety of plants (including food plants where they may be a biological defence): many citruses contain essential oils that are ...
Light sensitivity or photosensitivity refers to a notable or increased reactivity to light. Apart from vision , human beings have many physiological and psychological responses to light. In rare individuals an atypical response may result in serious discomfort, disease, or injury.
Erythropoietic protoporphyria (or commonly called EPP) is a form of porphyria, which varies in severity and can be very painful.It arises from a deficiency in the enzyme ferrochelatase, leading to abnormally high levels of protoporphyrin in the red blood cells (erythrocytes), plasma, skin, and liver. [2]
Photic retinopathy is damage to the eye's retina, particularly the macula, from prolonged exposure to solar radiation or other bright light, e.g., lasers or arc welders.The term includes solar, laser, and welder's retinopathy and is synonymous with retinal phototoxicity. [1]
Photosensitizers absorb light (hν) and transfer the energy from the incident light into another nearby molecule either directly or by a chemical reaction. Upon absorbing photons of radiation from incident light, photosensitizers transform into an excited singlet state.
Type III (aka hepatic photosensitivity) is the most common type of photosensitivity reaction seen in animals. [2] In this type, the photodynamic substance is phylloerythrin, a derivative of chlorophyll produced in the body. Normally, phylloerythrin is secreted into the intestine by the biliary system and excreted through the feces.