Mechanisms of phosphenes in irradiated patients.
Fiche publication
Date publication
septembre 2017
Journal
Oncotarget
Auteurs
Membres identifiés du Cancéropôle Est :
Dr VIGNOT Stéphane
Tous les auteurs :
Mathis T, Vignot S, Leal C, Caujolle JP, Maschi C, Mauget-Faÿsse M, Kodjikian L, Baillif S, Herault J, Thariat J
Lien Pubmed
Résumé
Anomalous visual perceptions have been reported in various diseases of the retina and visual pathways or can be experienced under specific conditions in healthy individuals. Phosphenes are perceptions of light in the absence of ambient light, occurring independently of the physiological and classical photonic stimulation of the retina. They are a frequent symptom in patients irradiated in the region of the central nervous system (CNS), head and neck and the eyes. Phosphenes have historically been attributed to complex physical phenomena such as Cherenkov radiation. While phosphenes are related to Cherenkov radiation under high energy photon/electron irradiation conditions, physical phenomena are unlikely to be responsible for light flashes at energies used for ocular proton therapy. Phosphenes may involve a direct role for ocular photoreceptors and possible interactions between cones and rods. Other mechanisms involving the retinal ganglion cells or ultraweak biophoton emission and rhodopsin bleaching after exposure to free radicals are also likely to be involved. Despite their frequency as shown in our preliminary observations, phosphenes have been underreported probably because their mechanism and impact are poorly understood. Recently, phosphenes have been used to restore the vision and whether they might predict vision loss after therapeutic irradiation is a current field of investigation. We have reviewed and also investigated here the mechanisms related to the occurrence of phosphenes in irradiated patients and especially in patients irradiated by proton therapy for ocular tumors.
Mots clés
choroidal melanoma, eye tumors, phosphenes, proton beam therapy, radiation therapy
Référence
Oncotarget. 2017 09 8;8(38):64579-64590