title: Prevention of scattered light-induced asthenopia and fatigue by a polarized filter.
abstract: BACKGROUND
  It has been well documented that a long-time irradiation of the eye by a strong light elicits eyestrain and fatigue. To elucidate the mechanism for the induction of light-induced fatigue and asthenopia, changes in the mouse were analyzed after white light-irradiation to the eye.
  
  
  METHODS
  C57BL/6j male mice were irradiated with white light in a specially designed room equipped with four mirrors covering all areas of its four walls to elicit diffused reflected light, and changes in their plasma levels of cortisol, INF-gamma, interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) were analyzed.
  
  
  RESULTS
  Irradiation of mice with scattered white light significantly decreased the motional activity of animals, suggesting the occurrence of fatigue. Biochemical analysis and enzyme-immunoassay revealed that the irradiation of mice significantly elevated the plasma levels of cortisol, IFN-gamma, IL-10 and TGF-beta. All these changes were not observed with mice irradiated with the light in a similar room not equipped with mirrors. These changes were successfully inhibited by a polarized glass filter but not by a non-polarized filter with a similar absorbance.
  
  
  CONCLUSIONS
  These observations suggest that irradiation of the eye by scattered reflected light stimulated a stress response via hypothalamo-pituitary-adrenal axis to enhance the secretion of cortisol from the adrenal grand and increase the plasma levels of cytokines.
authors.affiliation: Department of Biochemistry and Molecular Pathology, Osaka City University Medical School, Abeno, Osaka, Japan. hiramoto@msic.med.osaka-cu.ac.jp
authors.forename: Keiichi
authors.initials: K
authors.lastname: Hiramoto
authors.forename: Yurika
authors.initials: Y
authors.lastname: Yamate
authors.forename: Kumi
authors.initials: K
authors.lastname: Orita
authors.forename: Mika
authors.initials: M
authors.lastname: Jikumaru
authors.forename: Emiko
authors.initials: E
authors.lastname: Kasahara
authors.forename: Eisuke F
authors.initials: EF
authors.lastname: Sato
authors.forename: Shinzo
authors.initials: S
authors.lastname: Tamura
authors.forename: Masayasu
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000818:Animals; D001248:Asthenopia / Q000097:blood* / Q000209:etiology; D001522:Behavior, Animal / Q000528:radiation effects; D016207:Cytokines / Q000097:blood*; D005123:Eye / Q000378:metabolism; D005221:Fatigue / Q000097:blood* / Q000209:etiology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008027:Light / Q000009:adverse effects*; D008297:Male; D051379:Mice; D010913:Pituitary-Adrenal System / Q000378:metabolism*
chemical_list: D016207:Cytokines; D006854:Hydrocortisone