title: Retinal vessel measurement: comparison between observer and computer driven methods.
abstract: A method of semi-automated image analysis for the measurement of retinal vessel diameters is described. This was compared with an observer-driven method for reproducibility and accuracy. The coefficient of variation for the data from the semi-automated method was 1.5-7.5% (depending on the vessel diameter) compared to 6-34% with the observer-driven method. The mean vessel diameters using the observer-driven method tended to be higher; however, this did not reach significance. The speed and low inter- and intra-observer variability for the semi-automated method make it a useful technique for measuring retinal blood vessel diameters. A larger variability was found between photographs taken at different times. This may be due to changes in retinal vessel diameter with changes in retinal perfusion pressure during the cardiac cycle.
authors.affiliation: Department of Medicine, Royal Postgraduate Medical School, London, United Kingdom.
authors.forename: R S
authors.initials: RS
authors.lastname: Newsom
authors.forename: P M
authors.initials: PM
authors.lastname: Sullivan
authors.forename: S M
authors.initials: SM
authors.lastname: Rassam
authors.forename: R
authors.initials: R
authors.lastname: Jagoe
authors.forename: E M
authors.initials: EM
authors.lastname: Kohner
mesh_terms: D003930:Diabetic Retinopathy / Q000473:pathology; D005654:Fundus Oculi; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010781:Photography; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000473:pathology*; D012169:Retinal Vein / Q000473:pathology*