title: Safety assessment in macaques of light exposures for functional two-photon ophthalmoscopy in humans.
abstract: Two-photon ophthalmoscopy has potential forin vivoassessment of function of normal and diseased retina. However, light safety of the sub-100 fs laser typically used is a major concern and safety standards are not well established. To test the feasibility of safein vivotwo-photon excitation fluorescence (TPEF) imaging of photoreceptors in humans, we examined the effects of ultrashort pulsed light and the required light levels with a variety of clinical and high resolution imaging methods in macaques. The only measure that revealed a significant effect due to exposure to pulsed light within existing safety standards was infrared autofluorescence (IRAF) intensity. No other structural or functional alterations were detected by other imaging techniques for any of the exposures. Photoreceptors and retinal pigment epithelium appeared normal in adaptive optics images. No effect of repeated exposures on TPEF time course was detected, suggesting that visual cycle function was maintained. If IRAF reduction is hazardous, it is the only hurdle to applying two-photon retinal imaging in humans. To date, no harmful effects of IRAF reduction have been detected.
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, NY, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Schwarz
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, NY, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Sharma
authors.affiliation: Flaum Eye Institute, University of Rochester, Rochester, NY, USA.
authors.forename: William S
authors.initials: WS
authors.lastname: Fischer
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, NY, USA; Flaum Eye Institute, University of Rochester, Rochester, NY, USA.
authors.forename: Mina
authors.initials: M
authors.lastname: Chung
authors.affiliation: Department of Medical Devices, Polgenix Inc., Cleveland, OH, USA.
authors.forename: Grazyna
authors.initials: G
authors.lastname: Palczewska
authors.affiliation: Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Palczewski
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, NY, USA; Flaum Eye Institute, University of Rochester, Rochester, NY, USA; The Institute of Optics, University of Rochester, Rochester, NY, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Williams
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, NY, USA; Flaum Eye Institute, University of Rochester, Rochester, NY, USA; Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Hunter
keywords: (110.1080) Active or adaptive optics; (190.0190) Nonlinear optics; (330.3350) Vision - laser damage