title: Compact Laser Doppler Flowmeter (LDF) Fundus Camera for the Assessment of Retinal Blood Perfusion in Small Animals.
abstract: OBJECTIVE
  Noninvasive techniques for ocular blood perfusion assessment are of crucial importance for exploring microvascular alterations related to systemic and ocular diseases. However, few techniques adapted to rodents are available and most are invasive or not specifically focused on the optic nerve head (ONH), choroid or retinal circulation. Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).
  
  
  METHODS
  A confocal miniature flowmeter was fixed to a specially designed 3D rotating mechanical arm and adjusted on a rodent stereotaxic table in order to accurately point the laser beam at the retinal region of interest. The linearity of the LDF measurements was assessed using a rotating Teflon wheel and a flow of microspheres in a glass capillary. In vivo reproducibility was assessed in Wistar rats with repeated measurements (inter-session and inter-day) of retinal arteries and ONH blood velocity in six and ten rats, respectively. These parameters were also recorded during an acute intraocular pressure increase to 150 mmHg and after heart arrest (n = 5 rats).
  
  
  RESULTS
  The perfusion measurements showed perfect linearity between LDF velocity and Teflon wheel or microsphere speed. Intraclass correlation coefficients for retinal arteries and ONH velocity (0.82 and 0.86, respectively) indicated strong inter-session repeatability and stability. Inter-day reproducibility was good (0.79 and 0.7, respectively). Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.
  
  
  CONCLUSIONS
  We have demonstrated that, while not adapted for ONH blood perfusion assessment, this device allows pertinent, stable and repeatable measurements of retinal blood perfusion in rats.
authors.affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France.
authors.forename: Marielle
authors.initials: M
authors.lastname: Mentek
authors.affiliation: University of Applied Sciences and Arts of Western Switzerland, Institute of Systems Engineering, Sion, Switzerland.
authors.forename: Frederic
authors.initials: F
authors.lastname: Truffer
authors.affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France; Department of Ophthalmology, Grenoble University Hospital, Grenoble Alpes University, 38000, Grenoble, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Chiquet
authors.affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France.
authors.forename: Diane
authors.initials: D
authors.lastname: Godin-Ribuot
authors.affiliation: University of Applied Sciences and Arts of Western Switzerland, Institute of Systems Engineering, Sion, Switzerland.
authors.forename: Serge
authors.initials: S
authors.lastname: Amoos
authors.affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Loeuillet
authors.affiliation: University of Applied Sciences and Arts of Western Switzerland, Institute of Systems Engineering, Sion, Switzerland.
authors.forename: Mario
authors.initials: M
authors.lastname: Bernabei
authors.affiliation: University of Applied Sciences and Arts of Western Switzerland, Institute of Systems Engineering, Sion, Switzerland.
authors.forename: Martial
authors.initials: M
authors.lastname: Geiser
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D005654:Fundus Oculi; D007429:Intraocular Pressure / Q000502:physiology; D017078:Laser-Doppler Flowmetry / Q000379:methods*; D008297:Male; D055806:Microvessels / Q000502:physiology* / Q000648:ultrastructure; D009898:Optic Disk / Q000098:blood supply; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000502:physiology*; D012171:Retinal Vessels / Q000502:physiology* / Q000648:ultrastructure