title: Novel snapshot imaging of photoreceptor bleaching in macaque and human retinas.
abstract: OBJECTIVE
  Various methods have been used to obtain a topographic map of bleached photopigments in human retinas in the past. The purpose of this study was to determine whether the bleaching topography of the photoreceptors could be obtained by snapshot imaging reflectometry.
  
  
  METHODS
  Four to five fundus photographs of one rhesus monkey and three healthy human subjects were taken by white flashes at intervals of 4 s, with a commercial fundus camera with minimal modifications. The flash-induced reflectance increases (bleaching) were calculated by dividing the reflectance of the first image into the subsequent images, pixel by pixel.
  
  
  RESULTS
  The topography of the bleached macula corresponded well with the anatomical distribution of the cones. The ratio of reflectance changes in the center to that in the surrounding tissue was high for red and low for green and blue images. These results indicate that the reflectivity changes were not artifacts but were derived from changes in the photopigment density in the cones and rods.
  
  
  CONCLUSIONS
  The topography of bleached photoreceptors obtained with a commercial fundus camera from one monkey and three healthy human subjects showed that this technique has potential as a new clinical method for examining photoreceptor function in both normal and diseased retinas.
authors.affiliation: Laboratory of Visual Physiology, National Institute of Sensory Organs, Meguro-ku, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kazato
authors.forename: Naohisa
authors.initials: N
authors.lastname: Shibata
authors.forename: Gen
authors.initials: G
authors.lastname: Hanazono
authors.forename: Wataru
authors.initials: W
authors.lastname: Suzuki
authors.forename: Manabu
authors.initials: M
authors.lastname: Tanifuji
authors.forename: Kazushige
authors.initials: K
authors.lastname: Tsunoda
mesh_terms: D000328:Adult; D000818:Animals; D005260:Female; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D010775:Photic Stimulation; D010781:Photography; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology* / Q000528:radiation effects*; D012168:Retinal Pigments / Q000528:radiation effects
chemical_list: D012168:Retinal Pigments