title: A model for light toxicity of cultured human retinal pigment epithelium.
abstract: BACKGROUND
  The effect of visible light on human retinal pigment epithelial (HRPE) cells has not been characterized under conditions that provide strict thermal control.
  
  
  METHODS
  HRPE cells were isolated and grown to confluence. Cells were exposed to light in an incubator in which the cell temperature was controlled in response to a temperature sensor maintained in the tissue culture medium. Cells were exposed: (A) for 24, 36, and 48 h; and using a 24-h exposure followed by 24 h darkness; (B) at varying intensities of light using neutral density filters; (C) under a yellow filter; and (D) with a 12-h on-off cyclic light.
  
  
  RESULTS
  (A) Light exposure of 36 and 48 h resulted in significant cytotoxicity, while the initial 24-h exposure did not induce subsequent cytotoxicity. (B) Light irradiance levels from 43 to 54 mW/cm2 were required to demonstrate cytotoxicity. (C) Use of a yellow filter did not eliminate the observed cytotoxicity. (D) Cyclic exposure did not result in significant cytotoxicity.
  
  
  CONCLUSIONS
  This study establishes a model and basic parameters of light toxicity to HRPE cells in vitro using strict temperature control that may be used to evaluate photochemical injury to HRPE cells.
authors.affiliation: Department of Ophthalmology, Emory University, Atlanta, GA 30322, USA.
authors.forename: T W
authors.initials: TW
authors.lastname: Olsen
authors.forename: P
authors.initials: P
authors.lastname: Sternberg
authors.forename: R L
authors.initials: RL
authors.lastname: Reed
authors.forename: D P
authors.initials: DP
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002478:Cells, Cultured / Q000528:radiation effects; D002648:Child; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008027:Light / Q000009:adverse effects*; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D008954:Models, Biological; D010857:Pigment Epithelium of Eye / Q000473:pathology / Q000528:radiation effects*; D011833:Radiation Injuries, Experimental / Q000209:etiology* / Q000473:pathology; D013696:Temperature