title: Slow Cone Reflectance Changes during Bleaching Determined by Adaptive Optics Scanning Laser Ophthalmoscope in Living Human Eyes.
abstract: To investigate the changes in the reflectance of human cone photoreceptors by an adaptive optics scanning laser ophthalmoscope (AO-SLO) during photobleaching. A custom-built AO-SLO with an observation light of 840-nm was used to measure the cone densities and the reflectance changes during bleaching by 630 nm red light emitting diodes. Measurements were made at 1° and 3° temporal to the fovea within an area of 1° × 1° in 8 eyes of 8 normal subjects. After dark-adaptation, images of the cone mosaics were recorded continuously for 5-min before, 5-min during, and after 5-min of light stimulation with a sampling rate of 5-Hz. The first positive peak (P1) was observed at 72.2 ± 15.0-s and a second positive peak (P2) at 257.5 ± 34.5-s at 1°. The increase of the reflectance of P1 was significantly larger at 1° (34.4 ± 13.9%) than at 3° (26.0 ± 10.5%; P = 0.03, Wilcoxon's signed rank test). The average cone density at 1° (51123.13 ± 1401.23 cells/mm2) was significantly larger than that at 3° (30876.13 ± 1459.28 cells/mm2; P <0.001, Wilcoxon's signed rank test). The changes in the reflectance of the cones during bleaching by red light had two peaks. The two peaks may be caused by regeneration of cone photopigment during bleaching.
authors.affiliation: Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hirota
authors.affiliation: Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Fundamental Technology Sec, R&D Department, Topcon Corporation, Itabashi, Tokyo, Japan.
authors.forename: Suguru
authors.initials: S
authors.lastname: Miyagawa
authors.affiliation: Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanda
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Endo
authors.affiliation: Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, University Hospital Aachen RWTH Aachen University, Aachen, Nordrhein-Westfalen, Germany.
authors.forename: Tibor Karl
authors.initials: TK
authors.lastname: Lohmann
authors.affiliation: Department of Integrative Physiology, Graduate School of Medicine& Frontier Biosciences Osaka University, Suita, Osaka, Japan.
authors.forename: Tomomitsu
authors.initials: T
authors.lastname: Miyoshi
authors.affiliation: Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Morimoto
authors.affiliation: Department of Applied Visual Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujikado
mesh_terms: D000221:Adaptation, Ocular / Q000528:radiation effects*; D000328:Adult; D005584:Fovea Centralis; D006801:Humans; D007834:Lasers; D019721:Ophthalmoscopes; D055095:Optics and Photonics / Q000295:instrumentation*; D010775:Photic Stimulation; D038761:Photobleaching; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology* / Q000528:radiation effects*; D013997:Time Factors; D055815:Young Adult