title: Reproducibility and clinical application of a newly developed stabilized retinal laser Doppler instrument.
abstract: OBJECTIVE
  To describe a newly developed stabilized retinal laser Doppler instrument, to report the reproducibility of retinal blood flow measurements, and to present examples of its clinical application.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  The intrasession, intersession, and interobserver reproducibility of retinal blood flow measurements obtained using the Canon Laser Blood Flowmeter model CLBF 100 was assessed. Intrasession: the coefficients of variation (CV) for repeated measurements (5X) of retinal vessel diameter (D), time-average centerline blood velocity (V(av)), and blood flow (F) were calculated at 18 sites along temporal retinal arteries and 18 sites along temporal retinal veins using both eyes in six healthy volunteers. Intersession: the correlation coefficients and average differences between two sets of measurements at the same 36 retinal sites made by one examiner on two different days were calculated. Interobserver: the correlation coefficients and average differences between two sets of measurements at nine sites (five arterial and four venous) in five eyes of five of the volunteers made by two examiners on the same day were calculated. Results from two patients, one with branch retinal vein occlusion (BRVO), and one with central retinal vein occlusion (CRVO), are used to illustrate abnormal retinal circulatory characteristics.
  
  
  RESULTS
  intrasession: CV (mean +/- SD) for D, V(av), and F were 5.5% +/- 2.2%, 13.1% +/- 6.3%, and 13.8% +/- 4.7% in arteries and 3.5% +/- 2.1%, 11.9% +/- 5.9%, and 12.7% +/- 5.5% in veins. Intersession/interobserver: strong correlations between measurements made by one examiner on two different days and by two examiners on the same day were found in D, V(av), and F. Average differences in F were 16.4% +/- 12.8% for intersession and 12.6% +/- 7.0% for interobserver comparisons. Results from the patient with BRVO show marked differences in flow characteristics in the affected quadrant compared with an unaffected quadrant in the same eye, and to the fellow eye. Results from the patient with CRVO show a dramatic improvement in flow characteristics after clearing of the occlusion.
  
  
  CONCLUSIONS
  The reproducibility results and the fact that blood flow is measured in actual units of microl/min indicate that the instrument can be used for reliable comparison of blood flow characteristics at different retinal vascular sites in the same eye, at comparable sites in both eyes, and for comparison between patients and healthy control subjects.
authors.affiliation: Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan.
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Yoshida
authors.forename: Gilbert T
authors.initials: GT
authors.lastname: Feke
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Mori
authors.forename: Taiji
authors.initials: T
authors.lastname: Nagaoka
authors.forename: Naoki
authors.initials: N
authors.lastname: Fujio
authors.forename: Hironobu
authors.initials: H
authors.lastname: Ogasawara
authors.forename: Suguru
authors.initials: S
authors.lastname: Konno
authors.forename: J Wallace
authors.initials: JW
authors.lastname: Mcmeel
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000502:physiology*; D015356:Retinal Artery Occlusion / Q000503:physiopathology*; D012169:Retinal Vein / Q000502:physiology*; D012170:Retinal Vein Occlusion / Q000503:physiopathology*